Дисертації з теми "Staphylococcic"
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1
Bjertsjö, Rennermalm Anna. "Staphylococcal cell wall associated proteins : characteristics and host interactions /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-542-9/.
2
Lamers, Ryan Paul. "Evolutionary relationships among staphylococci and the prevention of Staphylococcus aureus nasal colonization." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4782.
Анотація:
Staphylococcus is a significant cause of human infection and mortality, worldwide. Currently, there are greater than 60 taxa within Staphylococcus, and nearly all are pathogenic. The collective potential for virulence among species of Staphylococcus heightens the overall clinical significance of this genus and argues for a thorough understanding of the evolutionary relationships among species. Within Staphylococcus, aureus is the most common cause of human infection, where nasal carriage of this bacterium is a known risk factor for autoinfection. The predisposition to infection by nasal carriers of S. aureus, and the ease with which strains are transferred between individuals, suggests that nasal carriage is a major vector for the transmission of virulent strains throughout the community. This hypothesis, however, has not been assessed in any great detail to identify the genetic relationships between clinical isolates of S. aureus and those strains being carried asymptomatically throughout the community. Also lacking within this field is a unified and robust estimate of phylogeny among species of Staphylococcus. Here, we report on a highly unified species phylogeny for Staphylococcus that has been derived using multilocus nucleotide data under multiple Bayesian and maximum likelihood approaches. Our findings are in general agreement with previous reports of the staphylococcal phylogeny, although we identify multiple previously unreported relationships. Regardless of methodology, strong nodal support and high topological agreement was observed with only minor variations in results between methods. Based on our phylogenetic estimates, we propose that Staphylococcus species can be evolutionarily clustered into 15 groups, and six species groups. In addition, our more defined phylogenetic analyses of S. aureus revealed strong genetic associations between both nasal carriage strains and clinical isolates. Genetic analyses of hypervariable regions from virulence genes revealed that not only do clinically relevant strains belong to identical genetic lineages as the nasal carriage isolates, but they also exhibited 100% sequence similarity within these regions. Our findings indicate that strains of S. aureus being carried asymptomatically throughout the community via nasal colonization are genetically related to those responsible for high levels of infection and mortality. Due to nasal carriage of S. aureus being a risk factor for autoinfection, standardized preoperative decolonization has become a major consideration for the prevention of nosocomial infection. Toward this end, we have identified the macrocyclic ?-defensin analogue RC-101 as a promising anti-S. aureus agent for nasal decolonization. RC-101 exhibited bactericidal effects against S. aureus in both epithelium-free systems, and ex vivo models containing human airway epithelia. Importantly, RC-101 exhibited potent anti-S. aureus activities against all strains tested, including USA300. Moreover, RC-101 significantly reduced the adherence, survival, and proliferation of S. aureus on human airway epithelia without any noted cellular toxicity or the induction of a proinflammatory response. Collectively, our findings identify RC-101 as a potential preventative of S. aureus nasal colonization.ID: 030646199; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 140-159).
Ph.D.
Doctorate
Molecular Biology and Microbiology
Medicine
Biomedical Sciences
3
Raupelytė, Eglė. "Koaguliazei teigiamų stafilokokų išskyrimas iš gyvūnų augintinių." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140305_133815-68093.
Анотація:
Darbo tikslas: nustatyti koaguliazei teigiamų stafilokokų paplitimą tarp gyvūnų augintinių.
Darbo uždaviniai:
1. išskirti koaguliazei teigiamus stafilokokus iš gyvūnų augintinių nosies ertmės;
2. išskirti koaguliazei teigiamus stafilokokus iš gyvūnų augintinių tiesiosios žarnos;
3. identifikuoti išskirtas stafilokokų padermes;
4. įvertinti įvairių veiksnių įtaką stafilokokų paplitimui;
5. nustatyti išskirtų stafilokokų atsparumą antimikrobinėms medžiagoms.
Darbo apimtis – 50 puslapių. Šiame darbe yra 6 lentelės bei 14 paveikslų. Magistro darbą sudaro 4 dalys. Pirmojoje dalyje apžvelgiami literatūros šaltiniai susiję su analizuojama tema, išskiriant koaguliazei teigiamų stafilokokų virulentiškumo veiksnius, atsparumą antimikrobinėms medžiagoms, sukeliamas ligas ir šių ligų gydymą. Aptariamas Staphylococcus aureus bei Staphylococcus pseudintermedius paplitimas ir paplitimą įtakojantys veiksniai. Antrojoje dalyje nurodyti tyrimo metodai, kuriais remiantis gauti duomenys tyrimų analizei. Trečiojoje dalyje analizuojami gauti tyrimo rezultatai pagal iškeltus uždavinius. Rezultatai pateikiami atsižvelgiant į statistinių duomenų patikimumą. Ketvirtoji dalis skirta literatūros apžvalgos ir tyrimo rezultatų skirtumų ir panašumų palyginimui.
Tyrimo metu iš gyvūnų augintinių nosies ertmės ir tiesiosios žarnos išskirti Staphylococcus aureus bei Staphylococcus pseudintermedius. Nustatyta, kad koaguliazei teigiamų stafilokokų paplitimas gyvūnų augintinių tarpe priklauso nuo gyvūnų... [toliau žr. visą tekstą]The The goal of the study: to determine prevalence of coagulase positive staphylococci in companion animals. The aim of the study: 1. to isolate coagulase positive staphylococci in nasal cavity of companion animals; 2. to isolate coagulase positive staphylococci in rectum of companion animals; 3. to identificate the isolated strains of staphylococci; 4. to evaluate risk factors for prevalence of staphylococci; 5. to determine antibiotic resistance in isolated staphylococci. The master study consists of 50 pages. It includes 6 tables and 14 pictures. The master study consist of 4 major chapters. The first chapter is dedicated to review of literature that is related with analized topic. This part includes coagulase positive staphylococci virulence factors, antibiotic resistance, diseases caused by staphylococci and treatment use. Furthermore chapter contains review of the prevalence and risk factors influenced the prevalence of Staphylococcus aureus and Staphylococcus pseudintermedius. The second chapter introduce with materials and methods, that were used in the research at this master study. In the third chapter the results of the research are presented. The results are presented according to the statistical reliability. The fourth chapter is the resemblance and similarity comparision of the literature review and master study research. In this master study Staphylococcus aureus and Staphylococcus pseudintermedius were isolated from nasal cavity and rectum of companion... [to full text]
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Nilsdotter, Åsa. "Coagulase-negative staphylococci in prosthetic hip infections /." Linköping : Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/med902s.pdf.
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Pacheco, Diana Isabel Ferreira. "Clínica e cirurgia em bovinos de aptidão leiteira: fatores de risco associados à prevalência de Staphylococcus spp. e coliformes no leite do tanque de explorações da Ilha de São Miguel, Açores." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/15906.
Анотація:
O presente relatório teve como base o estágio curricular em Clínica e Cirurgia de bovinos de aptidão leiteira realizado na Associação de Jovens Agricultores Micaelenses. A primeira parte deste relatório inclui a compilação da casuística acompanhada, seguida da segunda parte que corresponde à revisão bibliográfica sobre a mastite bovina. A terceira e última parte refere-se ao estudo desenvolvido em 100 explorações leiteiras da ilha de São Miguel, Açores. Do total das amostras de leite do tanque recolhidas nas explorações, 59% foram positivas a Staphylococcus aureus, 100% a Staphylococcus coagulase-negativos, 75% foram positivas a Escherichia coli e 35% a outros coliformes. Alguns dos fatores de risco em estudo, tais como a utilização de luvas e o pré-dipping, foram significativamente associados à prevalência dos agentes acima citados no leite do tanque. Verificou-se ainda uma influência significativa do Staphylococcus aureus na contagem de células somáticas no leite do tanque (P <0,001); DAIRY CATTLE MEDICINE AND SURGERY
Risk factors associated with the bulk-milk prevalence of Staphylococcus spp. and coliforms in dairy farms of São Miguel Island, Azores
ABSTRACT:
This report concerns to the academic internship in dairy cattle Medicine and Surgery performed at Associação de Jovens Agricultores Micaelenses. The first part of the report includes the compilation of accompanied casuistry, followed by the literature revision on bovine mastitis. The third and last part refers to a study in 100 dairy farms of São Miguel Island, Azores - Portugal. From the total bulk tank milk samples collected in the study dairy farms, 59% were positive to Staphylococcus aureus, 100% to coagulase-negative Staphylococci, 75% were positive to Escherichia coli and 35% to other coliforms. Several risk factors in study, such as gloves use and pré-dipping, were significantly associated with the prevalence of the agents mentioned above in bulk tank milk. Moreover, the study revealed a significant influence of Staphylococcus aureus in somatic cells count in bulk tank milk (P <0,001).
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Couto, Natacha. "Insights into the dynamics of methicillin-resistant staphylococci in animals : a focus on Staphylococcus pseudintermedius in dogs." Doctoral thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016. http://hdl.handle.net/10400.5/10771.
Анотація:
Tese especialmente elaborada para a obtenção do grau de Doutor em Ciências Veterinárias, especialidade de ClínicaStaphylococci are a group of bacteria with clinical, agricultural, and economic importance because of their wide range of virulence factors and ability to become resistant to antimicrobials. This thesis has pursued three main objectives: I. Determine the frequency of methicillin-resistant S. aureus (MRSA) strains in several animal species, identify the characteristics of strains present in animals and comparison with human strains MRSA nasal screening was performed in 71 horses and 307 calves, and the observed frequencies were 3% and 2%, respectively. Seventy-four MRSA isolated from 2001 to 2014 were characterized: fourteen spa types, three SCCmec types and three clonal complexes (CC) 5, CC22 and CC398, were found. Most isolates were multidrug-resistant. Fourteen MRSA CC398 strains had qac genes (13 qacG and 1 qacJ), while 4 isolates (three CC5 and one CC22) had insertions in the norA promoter gene. MRSA linages from pets (CC5 and CC22) harboured specific sets of virulence genes and a lower number of resistance genes than CC398 from livestock-animals. II. Reveal antimicrobial/biocide susceptibility patterns/trends and resistance genes in methicillin-resistant staphylococci (MRS) Several antimicrobial resistance patterns and genes were found in MRS from horses. Minimum bactericidal concentrations of biocides chlorhexidine acetate, benzalkonium chloride, triclosan and glutaraldehyde were lower than the recommended in-use concentrations for veterinary medicine, although two MRS carried plasmid-borne qacA and sh-fabI or qacB and qacH-like genes. An investigation on the evolution of resistance to 38 antimicrobials, corresponding mechanisms and molecular characteristics of 644 clinical Staphylococcus spp. isolates obtained from companion animals between 1999-2014 revealed resistance to the majority of antimicrobials and the number of mecA-positive strains increased significantly over time. Considering S. pseudintermedius, the methicillin-susceptible (MSSP) were genetically more diverse than methicillin-resistant (MRSP). All MRSP and two MSSP strains were multidrug- resistant, with several antimicrobial resistance genes identified. One MSSP isolate harbored a qacA and another a qacB gene. Three biocide products had high bactericidal activity (Otodine®, Clorexyderm Spot Gel®, Dermocanis Piocure-M®), while Skingel® failed to achieve a five log reduction in the bacterial counting. III. Study of the pathogenesis of S. pseudintermedius in dogs The agr type III predominated in MRSP. Five virulence genes were found in all strains and only spsO gene was significantly associated with MSSP. MSSP produced more biofilm on BHIB and BHIB+1% glucose than MRSP isolates. Several virulence genes encoding surface proteins and toxins were highly expressed in the MRSP strain (compared to MSSP). By whole proteome characterization of S. pseudintermedius through 2DE MALDI-TOF/TOF MS approach we were able to identify 367 unique proteins, of which 39 were surface proteins. By subsequent use of the serological proteome analysis (SERPA) approach we identified 4 antigenic proteins with promising features for vaccine development. These results indicate that MRS were widely disseminated in the studied animal population, the environment and people in contact with these animals. The resistant trends and mechanisms detected in MRS strains are worrying and make animals a reservoir of important MRS clones and genes. Biocides are still a good therapeutic choice, even in the presence of efflux genes. Higher expression of virulence genes may play a role in the rapid and widespread of MRSP clones. Dogs are able to mount an IgG-response against S. pseudintermedius and the proteins identified by the immune system can in the future be used as vaccine candidates.
RESUMO - Estudo da dinâmica de estafilococos meticilina-resistente em animais – um foco no Staphylococcus pseudintermedius em cães - Os estafilococos são um grupo de bactérias com importância clínica, agrícola e económica devido à ampla gama de fatores de virulência e pela sua capacidade de se tornarem resistentes aos antimicrobianos. Esta tese debruçou-se sobre três objetivos principais: I. Determinar a frequência de estirpes S. aureus meticilina-resistente (MRSA) em diversas espécies animais, identificar as características das estirpes presentes em animais e comparar com estirpes humanas Colhemos zaragatoas de 71 cavalos e 307 vitelos para pesquisa de MRSA, e observaramse frequências de 3% e 2%, respetivamente. Foram caracterizadas setenta e quatro estirpes MRSA isoladas entre 2001-2014: catorze tipos de spa, três tipos de SCCmec e três complexos clonais (CC) 5, CC22 e CC398, foram encontrados. A maioria das estirpes (74%) eram multirresistentes. Catorze estirpes de MRSA CC398 tinha genes qac (13 qacG e 1 qacJ), enquanto 4 (três CC5 e um CC22) tinham inserções no gene promotor norA. As linhagens de MRSA de animais de estimação (CC5 e CC22) tinham conjuntos específicos de genes de virulência e um menor número de genes de resistência do que as linhagens associadas aos animais de produção (CC398). II. Revelar padrões/ tendências de suscetibilidade antimicrobiana/biocida e genes de resistência em estafilococos meticilina-resistente (MRS) Foram encontrados vários padrões e genes de resistência antimicrobiana em MRS de cavalos. As concentrações bactericidas mínimas dos biocidas acetato de clorhexidina, cloreto de benzalcónio, triclosan e glutaraldeído foram menores do que as recomendadas em medicina veterinária, embora dois MRS tivessem os genes plasmídicos qacA e sh-fabI ou qacB e um qacH-semelhante. Uma investigação sobre a evolução da resistência a 38 antimicrobianos, mecanismos correspondentes e características moleculares de 644 Staphylococcus spp. clínicos obtidos de animais de companhia entre 1999-2014 revelou resistência à maioria dos antimicrobianos. O número de estirpes mecA-positivo aumentou significativamente ao longo do tempo. Quanto aos S. pseudintermedius, os meticilina-suscetível (MSSP) eram geneticamente mais diversos do que os meticilina-resistente (MRSP). Todos os MRSP e 2 MSSP eram multirresistentes, com vários genes de resistência identificados. Um MSSP tinha um gene qacA e outro um qacB. Três produtos biocidas tinham elevada atividade bactericida (Otodine®, Clorexyderm Spot Gel®, Dermocanis Piocure-M®), enquanto Skingel® não conseguiu atingir uma redução de 5 log na contagem bacteriana. III. Estudo da patogenicidade de S. pseudintermedius em cães O tipo III agr predominou nos MRSP. Cinco genes de virulência foram encontrados em todas as estirpes e só o gene spsO foi significativamente associado com MSSP. MSSP produziu mais biofilme em BHIB e BHIB + 1% glucose que as estirpes de MRSP. Vários genes de virulência que codificam proteínas e toxinas de superfície foram altamente expressos na estirpe MRSP (em comparação com MSSP). Através da caracterização do proteoma total de S. pseudintermedius pela abordagem 2DE MALDI-TOF/TOF MS fomos capazes de identificar 367 proteínas únicas, das quais 39 eram proteínas de superfície. Posteriormente utilizámos a análise do proteoma serológico (SERPA) que identificou quatro proteínas antigénicas com características promissoras para o desenvolvimento de vacinas. Estes resultados indicam que MRS estavam amplamente disseminados na população animal estudada, no ambiente e nas pessoas em contato com esses animais. As tendências de resistência e os mecanismos detetados em estirpes MRS são preocupantes tornando os animais um reservatório de clones MRS e genes. Os biocidas ainda são uma boa opção terapêutica, mesmo na presença de bombas de efluxo. Uma maior expressão de genes de virulência pode desempenhar um papel na rápida expansão de clones de MRSP. Os cães foram capazes de montar uma resposta IgG contra S. pseudintermedius e as proteínas identificadas pelo sistema imunológico podem, no futuro, ser utilizadas como candidatos vacinais.
7
Amiali, Mohamed Nassim. "Identification of antibiotic-resistant staphylococci and epidemiological typing of methicillin-resistant Staphylococcus aureus by Fourier transform infrared spectroscopy." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19525.
Анотація:
Staphylococci strains are among the most widespread multidrug-resistant nosocomial pathogens in Canada. Rapid and accurate identification and epidemiological typing of methicillin-resistant S. aureus (MRSA) and its discrimination from coagulase-negative staphylococci (CNS) and glycopeptide-intermediate S. aureus (GISA) are crucial for appropriate therapy and for monitoring and limiting intra- and inter-hospital spread of epidemic MRSA strains. Although pulsed-field gel electrophoresis and polymerase chain reaction methods for the identification of MRSA are reliable, they are technically demanding, time-consuming and inappropriate for routine clinical diagnosis. Moreover, no reliable method exists for discrimination of epidemic MRSA from sporadic MRSA and from GISA strains. The objective of the research described in this thesis was to investigate whether Fourier transform infrared (FTIR) spectroscopy could be used to distinguish MRSA from methicillin-susceptible S. aureus, borderline oxacillin-resistant S. aureus (BORSA), CNS, including methicillin-resistant CNS, and GISA. The application of FTIR spectroscopy for epidemiological typing of Canadian epidemic MRSA (CMRSA) strains as well as their discrimination from sporadic MRSA was also assessed. FTIR spectra were recorded from intact stationary-phase cells grown on Universal Medium (UM™) and deposited and dried on a ZnSe optical window, normalized, and converted to first-derivative spectra. Various chemometric approaches were employed to cluster the different phenotypes of staphylococci species and to subtype five CMRSA strains based on the similarity of their infrared spectral fingerprints in narrow spectral regions selected by visual inspection and by employing a singularvalue decomposition (SVD) algorithm. Pairwise separation of MRSA from MSSA, BORSA, CNS, MRCNS, and GISA was accomplished by using principal component analysis (PCA), self-organizing maps (SOM), and the K-nearest neighbors (KNN) algorithm. These chemometric techniques were also successfully employed for epidemiological typing of the five CMRSA strains and their discrimination from sporadic MRSA strains using a combination of different optimal spectral regions selected by SVD. These results demonstrate that FTIR spectroscopy has considerable potential as a rapid method for the identification of different phenotypes of staphylococci and epidemiological typing of MRSA.
8
Holt-Torres, Patricia. "Anti-Staphylococcal Activity of Variovorax paradoxus EPS." CSUSB ScholarWorks, 2017. https://scholarworks.lib.csusb.edu/etd/584.
Анотація:
Variovorax paradoxus EPS is a gram-negative rod isolated from the sunflower rhizosphere at CSUSB. Preliminary research has shown that Variovorax paradoxus EPS has anti-staphylococcal activity in liquid and solid co-culture. Anti-staphylococcal activity of Wild type and V. paradoxus EPS 𝚫4519 on 0.5% YE agar with embedded S. aureus AH1710 supports the idea that a soluble molecule is responsible for this activity, as the agar acted as a physical barrier between V. paradoxus EPS and S. aureus colonies. Preliminary genetic analysis of V. paradoxus EPS identified three loci that suitable candidates for the synthesis of a potential anti-staphylococcal small molecule. Preliminary data failed to detect expression at two of the three identified loci and a strain with a mutation at the third locus continues to produce anti-staphylococcal activity. We hypothesize that the microbial agent is expressed at a different locus or loci that have not yet been identified. These gene products are responsible for the synthesis of the microbial agent and are controlled by exposure to Staphylococcus aureus. Optimal growth conditions were identified for V. paradoxus EPS and S. aureus to demonstrate the formation of a zone of inhibition on Tryptic Soy Agar. The use of a V. paradoxus EPS Δ 4519 transposon library at optimal growth conditions allowed us candidate mutants with altered antimicrobial activity phenotypes. We identified 28 insertion sites that resulted in altered antimicrobial activities, which will allow us to identify the genes involved in this biosynthetic pathway.
9
Motta, Rogério Heládio Lopes. "Prevalencia, resistencia e patogenicidade de Staphylococcus aureus colhidos no ambiente clinico odontologico." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290193.
Анотація:
Orientadores : Thales Rocha de Mattos Filho, Francisco Carlos GroppoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Doutorado
Farmacologia, Anestesiologia e Terapeutica
Doutor em Odontologia
10
Björkqvist, Maria. "Coagulase-negative staphylococci septicaemia in newborns : aspects on host-bacterial interactions with special regard to neutrophil and endothelial response /." Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/med861s.pdf.
11
Lee, Chun-Yuan, Hung-Chin Tsai, Calvin M. Kunin, Susan SJ Lee, and Yao-Shen Chen. "Clinical and microbiological characteristics of purulent and non-purulent cellulitis in hospitalized Taiwanese adults in the era of community-associated methicillin-resistant Staphylococcus aureus." BioMed Central Ltd, 2015. http://hdl.handle.net/10150/610291.
Анотація:
BACKGROUND: The risk factors, microbial etiology, differentiation, and clinical features of purulent and non-purulent cellulitis are not well defined in Taiwan. METHODS: We conducted a retrospective cohort study of hospitalized adults with cellulitis in Taiwan in 2013. The demographic characteristics, underlying diseases, clinical manifestations, laboratory and microbiological findings, treatments, and outcomes were compared for patients with purulent and non-purulent cellulitis. RESULTS: Of the 465 patients, 369 had non-purulent cellulitis and 96 had purulent cellulitis. The non-purulent group was significantly older (p = 0.001) and was more likely to have lower limb involvement (p < 0.001), tinea pedis (p = 0.003), stasis dermatitis (p = 0.025), a higher Charlson comorbidity score (p = 0.03), and recurrence at 6 months post-infection (p = 0.001) than the purulent group. The purulent group was more likely to have a wound (p < 0.001) and a longer hospital stay (p = 0.001) and duration of antimicrobial therapy (p = 0.003) than the non-purulent group. The etiological agent was identified in 35.5 % of the non-purulent cases, with β-hemolytic streptococci the most frequent cause (70.2 %). The etiological agent was identified in 83.3 % of the purulent cases, with Staphylococcus aureus the predominant pathogen (60 %): 50 % of these were methicillin-resistant S. aureus (MRSA). In multivariable analysis, purulent group (odds ratio (OR), 5.188; 95 % confidence interval (CI), 1.995-13.493; p = 0.001) was a positive predictor of MRSA. The prescribed antimicrobial agents were significantly different between the purulent and non-purulent groups, with penicillin the most frequently used antimicrobial agent in the non-purulent group (35.2 %), and oxacillin the most frequent in the purulent group (39.6 %). The appropriate antimicrobial agent was more frequently prescribed in the non-purulent group than in the purulent group (83.2 % vs. 53.8 %, p < 0.001). CONCLUSIONS: The epidemiology, clinical features, and microbiology of purulent and non-purulent cellulitis were significantly different in hospitalized Taiwanese adults. Purulence was a positive predictor of MRSA as the causal agent of cellulitis. These findings provide added support for the adoption of the IDSA guidelines for empirical antimicrobial therapy of cellulitis in Taiwan.
12
Fonte, Ângela Isabel Espinha da. "Queijo de coalho do sertão Alagoano: enterotoxigenicidade de S. aureus pela reacção em cadeia polimerase (PCR)." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4164.
Анотація:
Mestrado em Engenharia Alimentar - Biotecnologia Microbiana - Instituto Superior de AgronomiaStaphylococcal enterotoxins (SE) are emetic toxins and are one of the main causes of food poisoning in humans. It is known that about 95% of staphylococcal food poisoning outbreaks are caused by SE types SEA to SEE. In this study, to investigate the distribution of staphylococcal enterotoxin genes (sea to see) in Staphylococcus aureus, 40 isolates obtained in Alagoas-Brazil from “coalho” cheese were analyzed by PCR. All S. aureus isolates were found to be positive for one or more se genes. Among the 40 isolates of S. aureus positive by PCR, the genotypes found were sea (32.5%), seb(22.5%), sec (42.5%), sed (25%), see (42.5%) and associations sea+sec (15%) and sec+see (30%). During this work, in seven samples of “coalho” cheese, obtained from four different industrial brands of sertão Alagoano the occurrence of S. aureus, Salmonella spp., Listeria and microorganisms indicators of fecal contamination was also determined. All of the samples were positive to coagulase positive staphylococci, and three samples (42.9%) were positive for Salmonella spp.. Regarding the contamination by total coliforms, all samples showed values above the limits established in the Brazilian legislation and 57.1% presented fecal coliforms. Such values are alarming since the majority of the analyzed products were inappropriate for consumption.
13
Lambein, Lore M. P. R. "An in vivo anti-staphylococcal drug screen using a zebrafish infection model implicates host autophagy in Staphylococcus aureus survival." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8934/.
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SILVA, Marilda Moreira da. "Determinação do perfil de resistência aos antimicrobianos em micro-organismos potencialmente patogênicos isolados em uma unidade de alimentação e nutrição de um hospital de ensino." Universidade do Oeste Paulista, 2017. http://bdtd.unoeste.br:8080/jspui/handle/jspui/1051.
Анотація:
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In order for food to provide, maintain or recover health it is necessary that it presents satisfactory sanitary control. It is known that one of the possible causes of hospital infection is the consumption of contaminated food, thus, providing safe food is essential to hospital nutrition services. Among foodborne diseases, those of bacterial origin have been pointed out as the most widespread public health problem in the world, especially Staphylococcus aureus, bacteria found mainly in the nasal cavities, mouth and skin of the human population. In this context, contamination of food, handlers and utensils is an important link among food, patients and diseases transmitted by food. Therefore, the the objective of this is study is to investigate the presence of S. aureus in food handlers, equipment, counter tops and utensils of a hospital's nutrition service, as well as the resistance profile of the isolated for antimicrobials. Samples of the environment, hands and nasal mucosa of employees of a nutrition service were collected with two sterile swabs in two different periods of the year (March and June), resulting in a total of 134 samples, which were submitted to characterization tests Biochemistry and morphotinorial (staining of gram, catalase and coagulase tests in tube), phenotypic evaluation by drug diffusion technique and D-test approach, in addition to the phenotypic biofilm characterization using Congo Red Agar. The results showed that the utensils, equipment and food handlers of the investigated hospital had high rates of colonization by S. aureus, mainly in the food production sector. It was also observed the high frequency of antimicrobial resistance, mainly erythromycin and the presence of multi-resistant microorganisms. A large number of positive samples were also found for the biofilm production, with totality for the samples of manipulators. We highlight the relevance of the data in virtue to the serious consequences and risks that can be triggered in the hospital environment. Educational actions and awareness measures were proposed in the institution, aiming at patient safety.
Para que a alimentação possa proporcionar, manter ou recuperar a saúde é necessário que a mesma apresente controle higiênico sanitário satisfatório. Sabe se que uma das possíveis causas de infecção hospitalar é o consumo de alimentos contaminados, sendo assim, fornecer alimentos seguros é essencial aos serviços de nutrição hospitalares. Das doenças transmitidas por alimentos, as de origem bacteriana são apontadas como o problema de saúde pública mais abrangente no mundo com destaque para Staphylococcus aureus, bactéria encontrada principalmente nas fossas nasais, boca e pele da população humana. Neste contexto, a contaminação de alimentos, manipuladores e utensílios é um importante elo entre alimento, pacientes e doenças transmitidas por alimentos. Diante disto, o presente estudo teve como objetivo investigar a presença de S. aureus nos manipuladores de alimentos, equipamentos, bancadas e utensílios do serviço de nutrição de um hospital, bem como o perfil de resistência dos isolados a antimicrobianos. Foram coletadas, com auxílio de swabs estéreis, amostras do ambiente, mãos e mucosa nasal de funcionários de um serviço de nutrição em dois períodos diferentes do ano (março e junho), resultando num total de 134 amostras, que foram submetidas a testes de caracterização bioquímica e morfotintoriais (coloração de gram, provas de catalase e coagulase em tubo), avaliação fenotípica por técnica de difusão da droga e teste de aproximação de discos-teste D, além da caracterização fenotípica de biofilme utilizando Ágar Vermelho Congo.. Os resultados demonstraram que os utensílios, equipamentos e manipuladores de alimentos do hospital investigado apresentaram altas taxas de colonização por S. aureus principalmente no setor de produção de refeições (cozinha). Foi observada também a alta frequência de resistência a antimicrobianos, principalmente a eritromicina e a presença de micro-organismos multirresistentes. Constatou-se também grande número de amostras positivas para a produção de biofilme, com totalidade para as amostras isoladas de manipuladores. Destacamos a relevância dos dados encontrados em virtude das graves consequências e riscos que podem desencadear no ambiente hospitalar. Ações educativas e medidas de conscientização foram propostas na instituição, visando à segurança do paciente.
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Souza, Alinne Guimarães de [UNIFESP]. "Caracterização fenotípica e molecular de amostras de Staphylococcus coagulase negativo isoladas de infecções da corrente sanguínea de pacientes de dois hospitais gerais da cidade de São Paulo." Universidade Federal de São Paulo (UNIFESP), 2009. http://repositorio.unifesp.br/handle/11600/9185.
Анотація:
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Staphylococcus coagulase negativo (SCoN) são importantes agentes etiológicos responsáveis por infecções relacionadas à assistência à saúde (IrAS) em infecções da corrente sanguínea. Em estudo retrospectivo foram avaliados SCoN isolados de pacientes com IrAS da corrente sanguínea em dois hospitais gerais da cidade de São Paulo no período de agosto de 2005 à agosto de 2007.Os isolados foram caracterizados a nível de espécies e testes de suscetibilidade aos antimicrobianos pelo Vitek® system e Vitek® 2. A presença do gene mecA e o tipo de SCCmec foram determinados por PCR multiplex. Staphylococcus epidermidis foi a espécie predominante seguido de S. hominis, S. haemolyticus, S. simulans, S. warneri, S. capitis e S. auricularis. Observou-se 88,2% de resistência à oxacilina nos isolados com 100% de concordância entre os discos de oxacilina e cefoxitina confirmados pelo gene mecA. Todos isolados foram suscetíveis à vancomicina e quatro isolados apresentaram resistência intermediária à teicoplanina pelo Etest®. Um S. epidermidis mostrou-se resistente à linezolida. O tipo de SCCmec predominante foi o tipo III seguido pelos tipos IV, I, II e V. Em 26,9% dos isolados mecA positivo não foram caracterizados nenhum tipo de SCCmec pelo protocolo utilizado.
Coagulase negative staphylococci (CoNS) are important etiologic agents responsible for healthcare related infection (HCRI) in bloodstream infections. In a retrospective study we evaluate CoNS isolated from patients with HCRI in bloodstream infections admitted to two general hospitals at São Paulo city, from August 2005 to August 2007. The isolates were characterized at species level and antimicrobial susceptibility tested by the Vitek® system and ViteK® 2. Oxacillin resistance was evaluated by oxacillin and cefoxitin discs. The presence of mecA gene and the SCCmec type were determined by multiplex PCR. Staphylococcus epidermidis was the predominant specie followed by S. hominis, S. haemolyticus, S. simulans, S. warneri, S. capitis and S. auricularis. Oxacillin resistance was observed in 88.2% of the isolates with 100% concordance between oxacilin and cefoxitin discs confirmed by mecA gene. All isolates were susceptible to vancomycin and four isolates revealed intermediate resistance to teicoplanin by Etest®. One S. epidermidis showed resistance to linezolide. The predominant SCC type was the type III followed by the types IV, I, II and V. In 26.9% positive mecA isolates we did not characterize the SCCmec type by the molecular protocol utilized.
TEDE
BV UNIFESP: Teses e dissertações
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Ai͏̈thamouda, Farida. "Etude échographique d'une staphylococcie pleuro-pulmonaire chez l'enfant : à propos d'un cas, revue de la littérature." Montpellier 1, 1993. http://www.theses.fr/1993MON11183.
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Colque-Navarro, Patricia. "Serum antibodies against Staphylococcus aureus antigens in healthy individuals and patients with invasive infections." Stockholm, 2010. http://diss.kib.ki.se/2010/978-91-7409-841-9/.
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Shannon, Oonagh. "Biological effects of extracellular fibrinogen binding protein (Efb) in Staphylococcus aureus infection /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-275-6/.
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Matar, Suzan. "Characterization of staphylococcal small colony variants and their pathogenic role in biomaterial-related infections with special reference to Staphylococcus epidermidis." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/12135/.
Анотація:
There are many surgical implanted devices in current use and all are prone to biomaterial-related infections (BRI) associated with staphylococcal biofilm formation. BRI are usually associated with S. epidermidis or S. Aureus and are characterized by treatment failure and chronicity resulting in reoperation, removal of the implant, and loss of function or death. Staphylococcal small colony variants (SCVs) may be generated by exposure to sublethal concentrations of antibiotics or nutrient limitation which may occur in biofilms. Although the characteristics of S. aureus SCVs have been well studied, little information on SCVs of S. epidermidis and their potential role in BRI is currently available. This study was designed to investigate the biochemical and phenotypic characteristics of S. epidermidis SCVs to further identify characteristics which may contribute to their ability to cause these increasingly important infections. Exposure to two to four times the gentamicin MIC led to the emergence of stable S. epidermidis SCVs, and the ability to produce SCVs was strain dependent. These variants were isogenic by PFGE and less immunogenic by western blotting, and SDS-PAGE analysis of whole cell preparations and cell wall fractions showed altered protein profiles when compared to wild type strains. S epidermidis SCVs were resistant to aminoglycosides such as amikacin and/or netilmicin and they were thiamine and/or menadione auxotrophs. Chemiluminescence assays showed a decreased ATP content reflecting the deficiency in electron transport systems which results in a growth rate – all characteristics similar to those of S. aureus SCVs. Analysis of virulence factor production indicated that S. epidermidis SCVs showed increased lipolytic and proteolytic activity when compared to those of S. aureus. Some S. epidermidis SCVs showed phase variation in exopolysaccharide production which enabled them to be more adherent to uncoated plastic -a property that may also be important for the later stages of development of biofilms. Invasion assays demonstrated that some S. epidermidis and S. aureus SCVs were internalised by HUVECs by a receptor-mediated mechanism which differed from that of the wild type strains. Interaction of staphylococci with HUVECs induced cytokine production but SCVs stimulated production of IL1, IL-6 and IL-8 at lower concentrations than their related wild type parents in the first 6 hours of co-incubation. SCVs were also less damaging to the HUVEC cell line after 24 hours when compared to wild type strains. This study supports the suggestion that a switch to the S. epidermidis SCV phenotype could be a mechanism exploited by the wild type strains to facilitate their survival inside the host. The chronicity and increased antibiotic resistance associated with BRI could in part, be explained by the characteristics of SCVs identified in this study. In particular the ability to survive intracellularly combined with reduced immunogenicity and resulting decreased cytokine production, may contribute to persistence of infection. Although SCVs are resistant to some antibiotics, surviving intracellularly may further protect staphylococci from other drugs which are unable to enter mammalian cells. Resistance may be further enhanced for some strains in biofilms where enhanced polysaccharide production may also limit antibiotic access.
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Long, James Paul. "Restoration of Host Resistance to Staphylococcus Aureus by Insulin Therapy and Characterization of Host Response to Coagulase- Negative Staphylococci in Intraperitoneal Infections /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487868114112399.
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Binatti, Vanessa Batista. "Relação entre a resistência a oxacilina e a produção de biofilme de amostras de origem comunitária e hospitalar pertencentes a diferentes espécies de Staphylococcus coagulase negativo." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7400.
Анотація:
Nas últimas décadas, os Staphylococcus coagulase-negativo, têm sido considerados como patógenos verdadeiros, sendo um dos principais grupos bacterianos responsáveis pelas infecções relacionadas a assistência a saúde (IRAS). O presente estudo teve como objetivo geral: avaliação da relação entre a resistência a oxacilina e a produção de biofilme de amostras Staphylococcus coagulase-negativo de origem comunitária e hospitalar. Neste sentido, foram desenvolvidos os seguintes objetivos específico: identificar ao nível de espécie os Staphylococcus coagulase-negativo; analisar por técnica fenotípica (Ágar vermelho do Congo) a produção de slime; avaliar quantitativamente, a produção de biofilme; correlacionar a produção de polissacarídeos extracelulares (slime) com a produção de biofilme; avaliar a relação da resistência a oxacilina como indicador da presença do gene mecA; avaliar a relação entre a concentração inibitória mínima e a concentração bactericida mínima para oxacilina; pesquisar a presença dos genes mecA, icaAD e atlE, pela técnica de PCR. Foi estudado um total de 150 amostras, sendo 50 isoladas de fômites, 50 isoladas de sangue e 50 isoladas de comunidade. Independente da origem, foram identificadas 14 espécies de Staphylococcus coagulase-negativo, sendo mais frequentes S. epidermidis 42,6%, S. haemolyticus 13,3% e S. cohnii cohnii 10,7%. A análise geral da expressão fenotípica de slime mostrou que 64% das amostras avaliadas eram produtoras de slime. Das 150 amostras testadas neste estudo, 95,3% foram produtoras de biofilme. Ao considerarmos a análise da quantificação do biofilme em relação às origens das amostras estudadas não encontramos diferenças significativas e a maioria das amostras foi considerada moderadamente produtora de biofilme. O gene mecA foi detectado em 6 amostras comunitárias, 34 amostras de fômites e 34 amostras de sangue. Não houve diferença significativa entre as amostras de fômites e sangue. Porém, houve diferença significativa entre as amostras de origem comunitária e as de origem hospitalar - fômites e sangue (p < 0,0001). Ao compararmos as três origens de isolamento quanto a presença do gene atlE observamos que houve diferença significativa (p = 0,0012) entre elas. Sendo, as amostras isoladas de sangue, as que apresentaram maior número de amostras que possuíam o gene atlE (n = 18). Das 150 amostras testadas observamos a presença do gene icaAD em 46% amostras comunitárias, 56% amostras de fômites e 60% amostras de sangue, não encontramos diferença significativa (p = 0,5750). Observamos uma correlação entre a resistência a oxacilina e a produção de slime, pois as amostras de origem hospitalar (fômites e sangue) apresentaram altos níveis de resistência a oxacilina e em sua grande maioria foram produtoras de slime. A espécie S. epidermidis foi a mais isolada e deve-se ressaltar que, quando comparada com as outras espécies, apresentou altos níveis de resistência a oxacilina, sendo a maioria produtora de slime e biofilme.In recent decades, coagulase-negative Stapphylococci have been considered as true pathogen, one of the major bacterial groups responsible for hospital infection. The present study aimed to: assess the relationship between oxacillin resistance and biofilm production samples coagulase-negative Stapphylococci of community and hospital. In this sense, we have developed the following specific objectives: to identify to species level coagulase-negative Staphylococci; analyze by phenotypic test (Congo red Agar) slime production, evaluate quantitatively the biofilm production; correlate the production of extracellular polysaccharides (slime) with biofilm production; evaluate the relationship of resistance to oxacillin as an indicator of the presence of the mecA gene; evaluate the relationship between minimal inhibitory concentration and minimum bactericidal concentration for oxacillin; investigate the presence of the mecA gene, atlE and icaAD, by PCR. We studied a total of 150 samples, 50 were isolated from fomites, 50 from community and 50 isolated from blood. Regardless of origin, 14 species of coagulase-negative Stapphylococci were identified , being more frequent 42.6% S.epidermidis, 13.3% S. haemolyticus and 10.7% S. cohnii cohnii. A general analysis of the phenotypic expression of slime showed that 64% of the samples were slime producers. Of the 150 samples tested in this study, 95.3% produced biofilm. When we consider the analysis of quantification of biofilm in relation to the origins of the samples studied we did not find significant differences and most of the samples were considered moderately biofilm producers. The mecA gene was detected in 6 community samples, 34 samples of fomites and 34 blood samples. There was no significant difference between the samples of blood and fomites. However, there was significant differences between the samples from the community and nosocomial - fomites and blood (p <0.0001). Comparing the three origins insulation as the presence of the gene atlE we observed a significant difference (p = 0.0012) between them. Being the isolated blood samples which showed the highest number of samples that had the gene atlE (n = 18). From the 150 tested samples we observed the presence of the gene icaAD 46% in community samples, 56% samples from fomites and 60% of blood samples, we found no significant difference (p = 0.5750). We observed a correlation between oxacillin resistance and slime production, because the nosocomial (fomites and blood) samples showed high levels of resistance to oxacillin and mostly were slime producers. The species S. epidermidis were the most isolated and it should be noted that, compared with other species, it showed high levels of resistance to oxacillin, mostly producing slime and biofilm.
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Tegnell, Anders. "The epidemiology and consequences of wound infections caused by coagulase negative staphylococci after thoracic surgery /." Linköping : Univ, 2002. http://www.bibl.liu.se/liupubl/disp/disp2002/med742s.pdf.
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Ferreira, Mariana de Andrade. "Caracterização fenotípica e genotípica de staphylococcus aureus isolados de queijo minas frescal industrial e artesanal." Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/5564.
Анотація:
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Staphylococcus aureus is an important foodborne pathogen, able to produce extracellular toxins and to express antimicrobial resistance. Among the foods involved in staphylococcal food poisoning, stands out the cheese, especially when manufactured under improper hygienic and sanitary conditions. The objectives of this study were to characterize Staphylococcus aureus isolated from artisanal and industrialized Minas frescal cheeses, to determine their antimicrobial susceptibility profile as well as the genetic similarity among the isolates. The isolates were also tested for staphylococcal enterotoxins (SE) genes and other virulence factors. Fifty-six artisanal raw milk cheeses sold at street fairs and 10 industrialized cheeses commercialized in supermarkets of Goiânia, Goiás were analyzed between June and August 2014. S. aureus was confirmed in 19 samples (33.9%) of artisanal cheese by detection of femA gene, in which 29 isolates were obtained. These isolates were submitted to the antimicrobial susceptibility test and classified into nine different profiles (A - I). Thirteen isolates (44.8%) were resistant to penicillin and three (10.3%) to tetracycline, with two (7.4%) resistant to both. The Multiplex PCR technique was performed to detect virulence genes that code for the production of hemolysins (Hla and Hlb), toxic shock syndrome toxin (TSST-1), exfoliative toxins (ETa and ETb) and enterotoxins (SEA - SEE, SEG - SEJ, SEM - SEO). Genes encoding TSST-1 and exfoliative toxins were not detected. All the isolates amplified for the hla gene and 14 (48.3%) for the hbl gene. The seh gene was the most frequently detected (n=11, 37.9%) followed by seo gene (n = 3; 10.3%), seg, sem and sen genes (n = 2, 6.9%) and sec and sei genes (n = 1, 3.4%). In one isolate (3.4%), four enterotoxins genes were detected, and in another, six (3.4%). The comparison performed by Pulsed Field Gel Electrophoresis technique revealed 18 different DNA banding patterns which were grouped into five clusters. The genotyping found high genetic similarity among the isolates. Identical isolates were obtained from different samples and one sample showed more than one genetically different isolate. It was identified up to four different isolates from the same sample. The high prevalence of S. aureus in a widely consumed product like Minas fresh cheese, as well as the detection of toxin encoding genes identified in this study, warns of the necessity to reduce the contamination levels in this type of cheese through monitoring and controling the production and trade of the product.
S. aureus é um importante patógeno de origem alimentar com capacidade de produção de toxinas extracelulares e resistência antimicrobiana. Entre os alimentos envolvidos em intoxicação alimentar estafilocócica, destaca-se o queijo, principalmente quando fabricado em condições higienicossanitárias impróprias. Os objetivos deste estudo foram caracterizar S. aureus isolados de queijo Minas frescal artesanal e industrializado, determinar o perfil de suscetibilidade a antimicrobianos, bem como determinar a similaridade genética entre os isolados. Os isolados foram também testados para genes de enterotoxinas estafilocócicas (SE) e outros fatores de virulência. Foram analisadas 56 amostras de queijo Minas frescal de fabricação artesanal e dez de fabricação industrial comercializados em feiras livres e supermercados de Goiânia-GO, coletadas entre junho e agosto de 2014. S. aureus foi confirmado em 19 amostras (33,9) de queijo artesanal através da detecção do gene femA, onde 29 isolados foram obtidos. Estes isolados foram submetidos ao teste de susceptibilidade aos antimicrobianos e classificados em nove diferentes perfis (A - I). Treze isolados (44,8%) foram resistentes à penicilina e três (10,3%) à tetracilina, sendo dois (7,4%) resistentes a ambos. A técnica de multiplex PCR foi realizada para a detecção de genes de virulência que codificam a produção de hemolisinas (Hla e Hlb), TSST-1, toxinas esfoliativas (ETa e ETb) e enterotoxinas (EEA - EEE, EEG - EEJ, EEM - EEO). Genes que codificam as toxinas TSST-1 e esfoliativa não foram detectados. Todos os isolados amplificaram para o gene hla e 14 (48,3%) para o gene hlb. O gene seh foi o mais frequentemente detectado (n=11; 37,9%), seguido do gene seo (n=3; 10,3%), genes seg, sem, sen (n=2; 6,9%) e os genes sec e sei (n=1; 3,4%). Um isolado (3,4%) amplificou genes para quatro enterotoxinas e outro (3,4%) para seis. A comparação dos 29 isolados de S. aureus feita por PFGE revelou 18 padrões de bandas diferentes de DNA agrupados em cinco clusters. A genotipagem demonstrou alta similaridade genética entre os isolados. Isolados idênticos foram obtidos de amostras diferentes e uma mesma amostra apresentou mais de um isolado geneticamente diferente. Identificou-se até quatro diferentes isolados da mesma amostra. A alta prevalência de S. aureus nas amostras de queijo Minas Frescal, bem como a detecção de genes para produção de toxinas, alertam para a necessidade de reduzir os níveis de contaminação neste tipo de queijo através de monitoramento e controle da produção e comércio do produto.
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Wilson, Lynne. "The investigation of the Staphylococcal Cassette Chromosome elements and Ciprofloxacin resistance in community Methicillin-Resistant Staphylococcus aureus Strains isolated in Western Australia." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/566.
Анотація:
In Western Australia, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) continues to be a public health concern. Antibiotic resistance places additional burdens on the community and health-care systems. Updates in MRSA typing and molecular characterisation techniques have benefits in furthering understanding of the evolution and emergence of MRSA and ultimately result in improvements in the control and prevention of its spread. Molecular studies not only give an understanding of how MRSA evolve but enable typing to be improved so that isolates can be better identified and improvements made to their control and prevention of spread.Forty-five prototypes of CA-MRSA lineages isolated in Western Australia (WA) between 2003 and 2006 were used in this study and were provided by the Australian Collaborating Centre for Enterococcus and Staphylococcus Species (ACCESS) Typing and Research Unit, situated at PathWest Laboratory Medicine, Royal Perth Hospital, Perth, WA, which is also associated with Curtin University, School of Biomedical Sciences, Molecular Genetics Research Unit in a joint collaboration.The polymorphic region of the staphylococcal protein A (spa) gene is considered a useful typing tool for differentiation of MRSA. A spa typing protocol was trialled in this study. To assess the method’s suitability for typing MRSA, all 45 isolates were tested to determine their spa type. Significant diversity was revealed with 28 different spa types identified. The spa type t002 was the most prevalent (7/45). Except for one isolate, which could not be typed, spa types correlated with the multi locus sequence typing (MLST) and clonal complex designations of the 45 CA-MRSA. A major outcome of this study has been the introduction of a standardised protocol for spa typing as a routine typing technique by the ACCESS Typing and Research Unit.Ciprofloxacin and other fluoroquinolones have restricted use in the community with their availability more accessible in hospitals and at the initiation of this study it was unusual to find ciprofloxacin resistance in CA-MRSA, however, eight of the prototype CA-MRSA possessed high-level ciprofloxacin resistance. This study therefore included an investigation of genetic mutations that result in resistance to ciprofloxacin in S. aureus. The subset of eight isolates were tested for mutations in the genes grlA, grlB, gyrA and gyrB. Sequence analysis revealed that all eight isolates contained point mutations resulting in amino acid changes at codon 80 in grlA and at codon 84 in gyrA. Additional mutations were seen in three of the eight isolates analysed. One isolate contained previously unreported mutations that may be associated with ciprofloxacin resistance. It was concluded that the CA-MRSA isolates could have developed resistance to ciprofloxacin when the patients may have received fluoroquinolones as a course of treatment for infection caused by other organisms such as Gram-negative bacteria.The staphylococcal cassette chromosome mec (SCCmec) is a genomic resistance island found in MRSA and a primary typing target for their classification. The SCCmecs of a subset of eight of the 45 prototype CA-MRSA isolates that had novel classifications were analysed as part of this study. The novel classifications for four of the eight were resolved into already classified SCCmec types, three of them had novel sub-types, two remained novel and the SCC region of one, WA MRSA-40 was completely sequenced. The J regions of the SCCmec elements were found to be structurally heterogeneous leading to the conclusion that they are “hot spots” for recombination, rearrangement and acquisition of genetic information that enables adaptation for survival of the host cell in changing environments.The SCC region of WA MRSA-40 was found to be a composite genomic island named SCCmecWA MRSA-40-CI (GenBank Accession No JQ746621). The 72,522 bp SCCmecWA MRSA-40-CI, was found to be comprised of three elements, ΨSCCpls, SCCsorbitol and SCCmecVT (5C2&5) integrated in tandem into the attB site of the conserved hypothetical protein gene orfX. Each element was delineated by direct and inverted repeats. ΨSCCpls is 11,736 bp and was homologous to the ΔJ1 region of SCCmec type I which encodes a pls gene. SCCsorbitol is 19,497 bp, and encodes a sorbitol operon, type 1 restriction modification genes, and a ccrA2B2 gene complex together with seven open reading frames. This is the first time that a sorbitol operon has been reported in a SCC element and only the second time that a sorbitol operon has been reported in a staphylococcus, with it previously being found in S. carnosus. Acquisition of a sorbitol operon has been linked to dietary sorbitol usage. The SCCmec of WA MRSA-40 is 41,289 bp and is highly homologous with the SCCmec VT of the Taiwan strain PM1; it carries a class C2 mec complex and two ccrC1 gene complexes with ccrC1, alleles 8 and 2. An insertion sequence ISSau4-like was found in the J2 region. Polymorphisms that generated premature stop codons that would prevent transposase activity and stabilise the mec complex were detected in the sequences of the transposases of IS431L and IS431R that flank the mec region.In conclusion this study has provided important and relevant information on the utilisation of spa typing for routine typing, the genetics and emergence of ciprofloxacin resistance in CA-MRSA and the analysis of the SCCmec region and SCC elements of CA-MRSA, particularly WA MRSA-40.
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Paiva, Rodrigo Minuto. "Concentração inibitória mínima de vancomicina para staphylococcus sp. coagulase negativa resistente à meticilina : comparação entre os métodos de microdiluição em caldo e etest e correlação com falha terapêutica em pacientes com bacteremia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/60789.
Анотація:
Vancomicina é o antimicrobiano de escolha no tratamento de bacteremias causadas por estafilococos resistentes à meticilina. No entanto, estudos recentes têm reportado que a vancomicina apresenta atividade reduzida contra Staphylococcus aureus resistentes à meticilina com concentrações inibitórias mínimas (CIMs) próximas do limite do ponto de corte de suscetibilidade, conforme critérios do CLSI, indicando falha terapêutica. Entretanto, existem poucos estudos à respeito dos Staphylococcus sp. coagulase negativa resistentes à meticilina (SCoNRM). Ademais, para determinação da CIM, deveria ser utilizado o método de referência microdiluição em caldo (MDC), mas a maioria dos laboratórios clínicos utiliza a técnica de Etest ou sistemas automatizados. Alguns estudos com S. aureus demonstraram discrepâncias entre MDC e Etest, contudo não existem dados referentes aos SCoN. Os objetivos deste estudo foram avaliar a correlação entre as CIMs de vancomicina determinadas pelas técnicas de MDC e Etest em 130 SCoNRM isolados de hemocultura, bem como verificar a relação entre valores de CIM e falha terapêutica entre pacientes com bacteremia por SCoNRM tratados com este antimicrobiano. A maioria dos resultados de CIM por MDC (98,5%) foram ≤1,0 mg/mL, enquanto o Etest apresentou 72,3% de CIM ≥ 1,5 mg/mL. As CIMs de vancomicina obtidas por Etest foram, em geral, uma a duas diluições maiores do que as CIMs obtidas por MDC. Os resultados indicam que a técnica de Etest gera valores de CIM consistentemente maiores do que os obtidos por MDC nos SCoNRM. Apenas 37 (28,5%) dos 130 pacientes com hemocultura positiva para SCoNRM apresentaram dados clínicos compatíveis com bacteremia. A maioria dos pacientes com bacteremia comprovada (n=24) apresentaram CIMs de vancomicina ≥1,5 mg/mL, sendo que 13 pacientes (35,1%) obtiveram CIM < 1,5 mg/mL. Este estudo não observou relação estatisticamente significativa entre valores de CIM de vancomicina que pudessem ser associados com falha terapêutica em pacientes com bacteremia por SCoNRM.Vancomycin is the first-line therapy for methicillin-resistant staphylococci bacteremia. However, recent studies have reported that vancomycin demonstrates reduced activity against methicillin-resistant Staphylococcus aureus bacteremia, with vancomycin MICs at the high end of the CLSI susceptibility range indicating treatment failure. There is, however, little data considering methicillin-resistant coagulase-negative staphylococci (MRCoNS) bacteremia. Besides, the reference method that should be used for MIC determination is the broth microdilution (BMD), but many clinical laboratories use the commercial Etest technique or automated systems. Some reports have showed a growing number of vancomycin MIC discrepancies between BMD and Etest method for S. aureus, but there are no studies about CoNS. The aims of this study were to evaluated the correlation between the vancomycin MIC determined by the Etest and the BMD method for a total of 130 MRCoNS bloodstream isolates as well as to examine the relationship between vancomycin MICs and failure among patients with MRCoNS bacteremia treated with vancomycin. The vast majority (98.5%) of MIC results by BMD were ≤1.0 mg/mL in contrast to MIC by Etest which majority (72.3%) was ≥1.5 mg/mL. The vancomycin MICs obtained by the Etest for the same isolates were, in general, one to twofold higher than those obtained by the BMD method. The results indicate that the Etest provides vancomycin MIC values consistently higher than those obtained by BMD method for MRCoNS. Only 37 (28.5%) out of the 130 patients with a positive MRCoNS bloodstream culture met the eligibility criteria to be considered bacteremic. The majority of these patients (n = 24, 64.9%) presented vancomycin MIC ≥ 1.5 mg/mL, in opposite to 13 patients (35.1%) with MIC < 1.5 mg/mL. This study did not observe any statistical significative relationship between vancomycin MIC and treatment failure.
26
Souza, Rodrigo Malzoni de. "Capacidade de resistência à fagocitose e atividade bactericida de neutrófilos por distintas cepas de estafilococos associadas à mastite em vacas primíparas e multíparas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/10/10136/tde-09042018-094125/.
Анотація:
O grupo de estafilococos não-aureus (SNA), frequentemente isolados de quartos mamários com mastite subclínica, ápice do teto e ambiente, possue variabilidade ecológica que desafia a compreensão da patogenia a estes atribuída. Os fatores espécie-específicos associados à essa infecção ainda não foram identificados e a susceptibilidade difere entre vacas e quartos e promove diferentes perfis de infecção. Com o objetivo de avaliar a resistência à fagocitose e atividade microbicida, comparou-se a viabilidade, a produção intracelular de espécies reativas de oxigênio (ERO) e a fagocitose de neutrófilos sanguíneos de vacas primíparas e multíparas frente a distintos isolados viáveis de estafilococos. Utilizou-se doze vacas sadias (seis primíparas e seis multíparas) em terço médio de lactação e SO isolados viáveis de estafilococos (38 SNA e 12 Staphylococcus aureus) de diferentes nichos ecológicos. A viabilidade de neutrófilos (P = 0,55), produção de ERO (P = 0,12) e atividade funcional dos fagócitos (P = 0,33) foram semelhantes entre as primíparas e multíparas testadas . Contudo, foram observadas diferenças (P ≤0,05) entre os distintos grupos de espécies e estirpes de estafilococos quanto ao estímulo da produção intracelular de ERO pelos neutrófilos e à fagocitose. S. chromogenes de origens distintas, ápice do teto (P = 0,01), infecção intramamária transiente (P < 0,01) e infecção intramamárias persistente (P < 0,01) estimularam mais a produção de ERO pelos neutrófilos do que as outras espécies. Todos isolados foram fagocitados pelos neutrófilos, mas S. chromogenes resistiram mais eficientemente que as outras espécies de SNA, principalmente, S. chromogenes isolados do ápice do teto (P < 0,01). S. haemolyticus isolados do ápice do teta (P = 0,02) e infecção intramamária transiente (P < 0,01), assim como, S. fleurettii (P < 0,01), foram substancialmente fagocitados do mesmo modo que S. aureus isolado de suabe nasa\\ (P = 0,03). Mais evidente do que possíveis variações entre as respostas mamárias de primíparas e multíparas é a variação entre os SNA. Quanto mais adaptado à mama, maior resistência à fagocitose.The group of non-aureus staphylococci (NAS), often isolated from mammary quarters with subclinical mastitis, teat apex and environment, has ecological variability that challenges the understanding of the pathogenesis attributed to them. The species-specific factors associated with this infection have not yet been identified and the susceptibility differs between cows and quarters and promotes different infection profiles. In order to evaluate the resistance to phagocytosis and I or microbicidal activity of these pathogens, the viability , intracellular production of reactive oxygen species (ROS) and blood neutrophil phagocytosis of primiparous and multiparous cows were compared to different viable isolates of staphylococci. Twelve healthy cows (six primiparous and six multiparous) were used in the middle third of lactation and 50 viable isolates of staphylococci (38 SNA and 12 Staphylococcus aureus) from different ecological niches. Neutrophil viability (P = 0.55), ROS production (P = 0.12) and phagocyte functional activity (P = 0.33) were similar among the primiparous and multiparous groups tested. However, differences (P <0.05) between the different groups of species and strains of staphylococci were observed for the stimulation of intracellular ROS production by neutrophils and phagocytosis. S. chromogenes of different origins, ceiling apex (P =0.01), transient intramammary infection (P <0.01) and persistent intramammary infection (P <0 .01) further stimulated the production of ROS by neutrophils than species. All isolates were phagocytosed by neutrophils, but S. chromogenes resisted more efficiently than the other SNA species, especially S. chromogenes isolated from the apex of the ceiling (P <0.01). S. haemolyticus isolated from apex to ceiling (P =0.02) and transient (P <0.01) intramammary infection, as well as S. fleurettii (P <0.01), were substantially phagocytosed in the same manner as S. aureus isolated from nasal swab (P = 0.03). More evident than possible variations between mammary responses of primiparous and multiparous is the variation between ANS. The more adapted to the breast, the greater resistance to phagocytosis.
27
Bes, Michèle. "Caractérisation de bactériophages de Staphylococcus epidermidis et Staphylococcus saprophyticus." Lyon 1, 1991. http://www.theses.fr/1991LYO10011.
Анотація:
Les staphylocoques coagulase-negatifs (scn), bacteries commensales de la peau et des muqueuses sont frequemment isoles au cours d'infections graves principalement chez des patients immunodeprimes ou porteurs de materiel etranger. L'absence de systeme de lysotypie des scn permettant de caracteriser ces souches pathogenes et de les differencier des couches isolees comme contaminants, nous a conduit a isoler nos propres bacteriophages. Deux lots de phages ont ete isoles de s. Epidermidis et s. Saprophyticus et evalues dans un premier temps comme marqueurs epidemiologiques en terme d'activite lytique, de reproductibilite et de pouvoir discriminant. Le nombre de souches typables reste faible: 23% avec les phages de s. Epidermidis et 8% avec les phages de s. Saprophyticus. Cependant nos sytemes presentent une bonne specificite et reproductibilite. L'etude au microscope electronique a montre que ces phages appartenaient au groupe morphologique b1 (queue longue et non contractile, tete isometrique) defini par ackermann et eisenstark et a la famille des siphoviridae. Trois sous-groupes ont pu etre constitues en fonction des dimensions: -phages de s. Epidermidis, -phages de s. Saprophyticus, morphotype i phages de s. Saprophyticus morphotype ii. Une correlation etroite entre la morphologie, la structure antigenique et les caracteres des acides nucleiques est observee pour les phages de s. Saprophyticus. Les phages de s. Epidermidis presentent quant a eux une heterogeneite au niveau des adn (27 a 79% d'homologie). A l'issue de ce travail, deux nouvelles especes de phages de staphylococcus saprophyticus sont proposees: une premiere representee par les phages 1139, 1314, 1259 (type morphologique ii), la deuxieme representee par les phages 1154a et 1405 (type i) est originale par la petite taille des virions
28
Böhm, Sacha [Verfasser], Peter F. [Akademischer Betreuer] Zipfel, Matthias [Akademischer Betreuer] Pletz, and Knut [Akademischer Betreuer] Ohlsen. "Immune evasion proteins from Staphylococcus aureus and therapeutic evaluation of staphylococcal complement-controlling proteins / Sacha Böhm. Gutachter: Peter F. Zipfel ; Matthias Pletz ; Knut Ohlsen." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2014. http://d-nb.info/1048558452/34.
29
Neves, Teresa Cabral Chora Claudino das. "Caracterização e avaliação da capacidade produtora de biofilmes em estafilococos coagulase negativos isolados de superfícies do ambiente fabril." Master's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2012. http://hdl.handle.net/10400.5/4585.
Анотація:
Dissertação de Mestrado em Segurança AlimentarOs objectivos deste estudo prendem-se com a identificação e caracterização tecnológica de isolados de estafilococos coagulase negativos provenientes de diferentes salsicharias tradicionais situadas no Alentejo e superfícies do ambiente fabril, avaliando-se a sua capacidade em formar biofilmes e persistência pós-limpeza e desinfecção. Isolaram-se amostras (N=78) de 4 superfícies diferentes (misturadora, picadora, parede da sala de enchimento, enchedora) provenientes de 3 Fábricas do Alentejo, após o qual se fez identificação de espécies de Staphylococcus. Caracterizou-se a sua aptidão tecnológica pelas provas da actividade lipolítica, proteolítica e nitrato-redutase. Para a avaliação fenotípica da capacidade de formar biofilmes utilizou-se o método Congo Red Agar - CRA, caracterizando-se os isolados de acordo com a cor das colónias às 24h e 48h de incubação, e na caracterização genotípica identificaram-se dois genes implicados na formação de biofilme: ica e Bap. Encontraram-se 35 isolados coincidentes com o género Staphylococcus, sendo dominantes 3 espécies diferentes: S. xylosus (N=19), S. saprophyticus (N=11) e S. equorum (N=5). A espécie S. equorum foi apenas isolada na Fábrica A, tendo aparecido na picadora (N=4) e na parede da sala da enchedora (N=1). A enchedora apresentava apenas isolados de S. saprophyticus (S4; N=9), enquanto a misturadora apresentava apenas S. xylosus (S1; N=7). Tanto a picadora como a parede da sala de enchimento apresentavam isolados das 3 espécies. Apenas 20 dos 35 Staphylococcus apresentaram actividade lipolítica, 19 destes identificados como S. xylosus. A actividade proteolítica foi evidenciada por apenas 7 isolados (S. equorum e S. xylosus) e todos pertencentes à Fábrica A. Das 3 espécies identificadas como CNS, 26 isolados apresentaram actividade nitrato-redutase, havendo isolados das 3 espécies consideradas. Maioritariamente os isolados em estudo (N=33) foram formadores de visco/biofilme pelo método fenotípico. Todas as amostras onde se detectou o gene ica eram pertencentes à espécie S. xylosus (N=5) e expressavam forte capacidade (++) formadora de biofilmes (N=5:ica:+;CRA:++). Dos isolados identificados com o gene Bap (N=6), havia estirpes das espécies S. xylosus (N=4) e S. saprophyticus (N=2), havendo 1 destes que apresentou uma fraca capacidade formadora de biofilme (+) (N=5:Bap+;CRA++ e N=1:Bap+;CRA+). Duas estirpes de S. xylosus (S3B5 e S3B7) foram positivas para o ica e para o Bap simultaneamente (N=2:ica+;Bap+). Considerou-se a estirpe S. xylosus S2M6 com potencial utilização como starter uma vez que apresentava características de interesse tecnológico e era fraca formadora de biofilme, não apresentando nenhum dos genes ica e Bap.
ABSTRACT - Characterization and forming biofilms ability from Coagulase Negative Staphylococci isolates in meat processing surfaces - The aims of this work were the identification and technological characterization of Staphylococci isolates obtained from 4 different environment surfaces in 3 meat processing workshops from Alentejo region and to determine their ability to form biofilms. There were 78 samples isolated from 4 environment surfaces (mixing machine, mincing machine, wall from the stuffing room and stuffing machine) in 3 different meat processing workshops and they were identified in order to determine isolates from the genus Staphylococcus. It has also been characterized their tecnological ability for lipolitic, proteolitic and reducing-nitrate activities. For the phenotypic evaluation to form biofilms we used the Congo Red Agar method and by PCR were searched the ica and Bap genes. 35 isolates were identified by PCR as Staphylococcus: 19 S. xylosus, 11 S. saprophyticus and 5 S. equorum. S. equorum (N=5) was only found in workshop A at the surface of mincing machine (N=4) and on the wall of stuffing room (N=1). The stuffing machine had only isolates from S. saprophyticus (S4; N=9), and the mixing machine presented only S. xylosus (S1; N=7). The mincing machines as well the wall of stuffing room had isolates from the 3 species. 20 of the 35 CNS presented lipolitic activity and 19 of these were S. xylosus. Only 7 isolates (S. xylosus and S. equorum) had proteolitic activity and they were all from workshop A. The reducing-nitrate activity was presented by 23 CNS from the 3 identified species. 33 Staphylococcus were strong biofilm formers but only 5 were positive for ica gene and 6 for Bap gene. Every ica positive were S. xylosus and all were strong biofilm formers (N=5:ica:+;CRA:++). The Bap positive isolates were from S. xylosus (N=4) and S. saprophyticus (N=2) species. From the Bap positive isolates it was found one weak positive (N=5:Bap+;CRA++ and N=1:Bap+;CRA+). Two strains of S. xylosus (S3B5 and S3B7) were positive for ica and for Bap genes simultaneously. We considered S. xylosus S2M6 as a potential strain starter because it presented technological abilities and was a weak biofilm former and didn’t present ica nor Bap genes.
30
Hurtault, Sylvie. "Etude épidémiologique de l'émergence de staphylococcus aureus résistants à la fosfomycine dans une unité de soins intensifs." Bordeaux 2, 1989. http://www.theses.fr/1989BOR23035.
31
Hussain, Malik Asif. "Comparative study of coagulase negative Staphylococci (CoNS) from clinical isolates, skin and nasal sources." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/47603/1/Malik_Hussain_Thesis.pdf.
Анотація:
Staphylococci are important pathogenic bacteria responsible for a range of diseases in humans. The most frequently isolated microorganisms in a hospital microbiology laboratory are staphylococci. The general classification of staphylococci divides them into two major groups; Coagulase-positive staphylococci (e.g. Staphylococcus aureus) and Coagulase-negative staphylococci (e.g. Staphylococcus epidermidis). Coagulase-negative staphylococcal (CoNS) isolates include a variety of species and many different strains but are often dominated by the most important organism of this group, S. epidermidis. Currently, these organisms are regarded as important pathogenic organisms causing infections related to prosthetic materials and surgical wounds. A significant number of S. epidermidis isolates are also resistant to different antimicrobial agents. Virulence factors in CoNS are not very clearly established and not well documented. S. epidermidis is evolving as a resistant and powerful microbe related to nosocomial infections because it has different properties which independently, and in combination, make it a successful infectious agent, especially in the hospital environment. Such characteristics include biofilm formation, drug resistance and the evolution of genetic variables. The purpose of this project was to develop a novel SNP genotyping method to genotype S. epidermidis strains originating from hospital patients and healthy individuals. High-Resolution Melt Analysis was used to assign binary typing profiles to both clinical and commensal strains using a new bioinformatics approach. The presence of antibiotic resistance genes and biofilm coding genes were also interrogated in these isolates.
32
Quirk, Tracy Elizabeth. "Coagulase-negative staphylococci mastitis management." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/T_QUIRK_042310.pdf.
Анотація:
Thesis (M.S. in animal sciences)--Washington State University, May 2010.Title from PDF title page (viewed on July 22, 2010). "Department of Animal Sciences." Includes bibliographical references (p. 53-65).
33
McLaws, Fiona Blair. "Fusidic Acid Resistance in Staphylococci." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503286.
34
Planchon, Stella. "Aptitude de Staphylococcus carnosus et Staphylococcus xylosus à former des biofilms." Phd thesis, Clermont-Ferrand 2, 2006. http://tel.archives-ouvertes.fr/docs/00/69/39/34/PDF/2006CLF21661.pdf.
Анотація:
Staphylococcus xylosus et Staphylococcus carnosus sont utilisés comme ferments de salaisons. S. Xylosus est fréquemment isolé dans l'environnement des ateliers de transformation alimentaire alors que S. Carnosus l'est rarement. Ainsi, nous avons étudié la capacité de ces deux espèces à former des biofilms sur divers supports abiotiques. Les souches de S. Carnosus sont hydrophiles, adhèrent à des supports hydrophiles mais ne forment pas de biofilms. Certaines souches de S. Xylosus sont hydrophiles, d'autres moyennement hydrophobes et elles forment des biofilms quelque soit le support. S. Xylosus C2a, choisie comme souche d'étude, forme des biofilms denses avec des agrégats intercelluaires séparés par des canaux et englués dans une matrice constituée de polysaccharides dont la synthèse ne semble pas liée au gène icaA. Nous avons mis en evidence les gènes atl et bap codant des protèines de surface impliquées dans la formation de biofilm chez S. Aureus. Pour étudier l'ensemble des protéines de surface impliquées, nous avons développé une méthode d'analyse des protéines pariétales et membranaires. Un total de 101 protéines a été identifié dont 51 sont prédites comme protéines de surface et seulement 9 sont cmmunes aux deux fractions. La comparaison des profils protéiques des fractions pariétales, membranaires et intracellulaires a révélé une expression différentielle de 115 protéines dont 74 sont surexprimées en mode sessile et 41 en planctonique. Cette étude a révélé la modification de nombreuses voies métabolliques. Leur analyse permettra de mieux appréhender les mécanismes mis en jeu par S. Xylosus lors de sa croissance en biofilm
35
Santiago, Neto Waldemir. "Avaliação de fatores de risco para resistência múltipla a antimicrobianos em bactérias da glândula mamária do gado de leite em sete regiões do Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/127123.
Анотація:
Estafilococos têm sido relatados como os agentes mais prevalentes de mastite bovina. Este gru-po bacteriano pode transportar múltiplos elementos de resistência provenientes inclusive de outras populações bacterianas, tornando-se um grande problema de saúde pública, uma vez que também está envolvido em vários processos de doença em humanos, incluindo infecções da pele e dos tecidos moles, septicemia, osteomielite e pneumonia. A caracterização do perfil de resis-tência dos estafilococos aos antimicrobianos é importante para controlar a sua disseminação. O presente trabalho avaliou a distribuição de multirresistência entre mais de 3.500 isolados de um estudo transversal repetido, realizado entre 2010 e 2011 nas principais regiões produtoras de leite do Brasil. As bactérias foram classificadas de acordo com métodos fenotípicos e os padrões de resistência antimicrobiana foram determinados pelo teste de difusão em disco ao invés de testes moleculares e ensaios quantitativos. Para avaliar os principais fatores relacionados à vari-ável resposta – proporção de bactérias resistentes a três ou mais classes de antimicrobianos, ou multirresistência – diversas variáveis explicativas foram acessadas por meio de um questionário epidemiológico. Um modelo misto foi construído com um componente aleatório multinível, a saber, a variação de multirresistência entre as bacias leiteiras (segundo nível) e a variação dass propriedades em cada bacia (primeiro nível) durante os quatro momentos de amostragem, ou seja, a variação entre-sujeitos e intra-sujeitos, respectivamente. A avaliação dos perfis de resis-tência revelou que as penicilinas, seguidas por tetraciclina e sulfonamida, foram os antimicrobi-anos com menor eficácia em estafilococos (n = 3009). Estafilococos coagulase negativa pare-cem ter semelhanças com S. aureus e alguns outros estafilococos coagulase positiva testados, demonstrando um padrão de grupo com moderada resistência a múltiplas drogas. Ilustrativa-mente, alguns estreptococos (n = 480) também foram submetidos a testes de suscetibilidade a antimicrobianos, os quais mostraram moderada a alta resistência à tetraciclina, gentamicina e clindamicina. O modelo misto indicou que o tratamento de mastite feito de imediato, a aplicação de terapia antimicrobiana pelo próprio produtor ao invés de um veterinário, e a interação entre este último fator e o sistema de produção intensivo aumentou a probabilidade de resistência múltipla em nível de rebanho. O coeficiente de correlação intraclasse (ICC) foi baixo e mostrou que a maior parte da variação de resistência múltipla é explicada pelas características em nível de hospedeiro, seguido por fatores em nível de rebanho (ICC = 0,126). Esses fatores são exem-plos importantes de como o uso leigo de antimicrobianos em vacas leiteiras tem grande poten-cial para seleção, expansão e manutenção de populações de bactérias resistentes a múltiplas drogas em ambientes de produção animal, em especial nos mais intensivos.Staphylococci have already been reported as the most prevalent mastitis agents. Such bacterial species can carry multidrug-resistant elements coming from other bacteria species, and so on are becoming a great public health concern, once it is also involved in several human disease. The characterization of their antimicrobial resistance profile is important to better control their dissemination. The present work evaluated the distribution of multidrug-resistance among more than 3500 isolates from a repeated cross-sectional study performed from 2010 to 2011 in the main dairy regions of Brazil. The bacteria were classified according to phenotypic methods and the antimicrobial resistance patterns were determined by disk diffusion. To evalu-ate the main factors related to the response variable – the proportion of bacteria resistant to three or more antimicrobial classes, or multidrug resistance – several explanatory variables were accessed by means of an epidemiological questionnaire. A multivariable mixed model was created to access the strength of association between several putative risk factors and re-sistance to multiple drugs. Resistance profiles evaluation revealed that penicillins, followed by tetracycline and sulfonamide, were the antimicrobials with lower effectiveness in staphylococci (n = 3009). Coagulase negative staphylococci seemed to have similarities with coagulase posi-tive tested, performing moderate resistance pattern to multiple drugs. Some streptococci (n = 480) were also submitted to antimicrobial susceptibility tests, and showed moderate to high resistance to tetracycline, gentamycin and clindamycin. The mixed model indicated that mastitis treatment made immediately rather than cautiously; applicaton of antimicrobial therapy by the producer itself rather than a veterinarian practitioner; and the interaction between the produc-er as applicator and the intensive, modern production system increased the likelihood of multi-ple-resistance at herd level. The low intraclass correlation coefficient at region level showed that resistance variance is most explained at herd level, and it characteristics, rather than re-gion level. Probably the host level factors not evaluated in this study explains more than the herd level factors, but, considering the coverage of our study, these factors give us insights of how cattle antimicrobial consumption can affect the maintenance and expansion of multidrug resistant bacteria populations in animal production environments.
36
Roberts, Jill Carolyne. "Characterization of Community-acquired Methicillin-resistant Staphylococcus aureus by Pulsed-field Gel Electrophoresis, Multilocus Sequence Typing, and Staphylococcal Protein A Sequencing: Establishing a Strain Typing Database." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001489.
37
Wernérus, Henrik. "Engineering of staphylococcal surfaces for biotechnological applications." Doctoral thesis, KTH, Biotechnology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3450.
Анотація:
The engineering of bacterial surfaces has in recent yearsattracted a lot of attention with applications in manydifferent areas of bioscience. Here we describe the use of twodifferent surface display systems for the gram-positivebacteria Staphylococcus carnosus and Staphylococcus xylosus invarious biotechnological applications.
Environmental microbiology currently attracts a lot ofattention since genetically engineered plants and bacteriamight be used as bioadsorbents for sequestration of toxicmetals. Bacterial surface display of metal-binding peptidesmight enable recycling of the biomass by desorption ofaccumulated heavymetals. In an attempt to recruitstaphylococcal display systems for bioremediation purposes,polyhistidyl peptides were successfullly displayed on thesurface of recombinant S. carnosus and S. xylosus cells.Whole-cell Ni2+-binding assays demonstrated that therecombinant cells had gained metal-binding capacity compared towild-type cells.
Tailor-made, metal-binding staphylococci was created using apreviously constructed phage-display combinatorial proteinlibrary based on a fungal cellulose-binding domain (CBD)derived from the cellobiohydrolase Cel7A of Trichoderma reseii.Novel metal-binding CBDs were generated through a phagemediated selection procedure. Selected CBD variants, now devoidof cellulose binding, were randomly selected and sequenceanalysis of selected variants revealed a marked preference forhistidine residues at the randomized positions. Surface displayof these novel CBD variants resulted in recombinantstaphylococci with increased metal-binding capacity compared tocontrol strains, indicating that this could become a generalstrategy to engineer bacteria for improved binding to specificmetal ions.
Directed immobilization of cells with surface displayedheterologous proteins have widespread use in modernbiotechnology. Among other things they could provide aconvenient way of generating biofilters, biocatalysts orwhole-cell diagnostic devices. It was therefore investigatedwhether directed immobilization of recombinant staphylococci oncotton fibers could be achieved by functional display of afungal cellulose-binding domain (CBD). Recombinant S. carnosuscells with surface anchored CBDs from Trichoderma reseii Cel6Awere found to efficiently bind to cotton fibers creating almosta monolayer on the fibrous support. The co-expression of thisCBD together with previously described metal-binding proteinson the surface of our staphylococci would create means fordeveloping effective bioadsorbents for remediationpurposes.
The original plasmid vector, designed for heterologoussurface display on recombinant S. carnosus cells has exhibitedproblems related to structural instability, possibly due to thepresence of a phage f1 origin of replication in the vectorsequence. This would be a problem if using the vector systemfor library display applications. Therefore, novel surfacedisplay vectors, lacking the phage ori were constructed andevaluated by enzymatic and flow cytometric whole-cell assays.One such novel vector, pSCXm, exhibited dramatically increasedplasmid stability with the retained high surface density ofexpressed heterologous proteins characteristic for the originalS. carnosus display vector, thus making it potentially moresuitable for library display applications.
The successful engineering of our staphylococcal displaysystem encouraged us to further evaluate the potential to usethe staphylococcal system for display of combinatorial proteinlibraries and subsequent affinity based selections using flowcytometric cell sorting. A model system of recombinant S.carnosus cells with surface displayed engineered protein Adomains was constructed. It was demonstrated that target cellscould be sorted essentially quantitatively from a moderateexcess of background cells in a single sorting-step.Furthermore, the possibility of using staphylococcal surfacedisplay and flow cytometric cell sorting also for specificenrichment of very rare target cells by multiple rounds ofcell-sorting and in between amplification was demonstrated.
Key words:affibody, albumin binding protein, bacterialsurface display, cell immobilization, bioremediation,combinatorial protein engineering, flow cytometry,Gram-positive, metal binding, staphylococcal protein A,Staphylococcus carnosus, Staphylococcus xylosus, whole-celldevices
38
Ras, Geoffrey. "Production de monoxyde d’azote par les staphylocoques à coagulase négative : implication de l’oxyde nitrique synthase de staphylococcus xylosus." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC029/document.
Анотація:
Les staphylocoques à coagulase négative (SCN) sont des bactéries fréquemment isolées de viandes et de produits carnés. Parmi les SCN, seules les deux espèces S. xylosus et S. carnosus sont utilisées comme ferments dans les produits carnés. Dans ces produits, il est d’usage d’ajouter du nitrate/nitrite pour le développement de la couleur typique des salaisons. Les staphylocoques participent au développement et à la stabilité de la couleur en réduisant le nitrate en nitrite via leur activité nitrate réductase. Le nitrite est chimiquement réduit en monoxyde d’azote (NO), qui se lie au fer de l’hème de la myoglobine pour former la nitrosomyoglobine, un pigment rouge et stable. Le contexte actuel vise à réduire l’utilisation du nitrate/nitrite afin de limiter le risque de formation de composés N-nitrosés tels que les nitrosamines. Il a été montré que les bactéries pouvaient synthétiser du NO à partir d’une oxyde nitrique synthase (NOS). Le gène nos a été identifié dans une collection de souches de SCN isolées de viande. La séquence protéique de la NOS est fortement conservée entre les espèces. Pour mettre en évidence la production de NO, un test basé sur la conversion de metmyoglobine en pigments rouges, l’oxymyoglobine et la nitrosomyoglobine, a été utilisé. Le nitrosohème contenu dans la nitrosomyoglobine a été extrait. La formation du nitrosohème, chez un mutant de délétion du gène nos de la souche S. xylosus C2a, est fortement réduite en condition limitée en oxygène et abolie en condition aérobie. De plus, la NOS de S. xylosus C2a est impliquée dans la réponse à un stress oxydant. Afin de déterminer le potentiel de production de NO de souches de S. xylosus et d’autres espèces de SCN, leur capacité à former de la nitrosomyoglobine a été évaluée. Cette formation est espèce- et souche-dépendante. Les souches de S. xylosus ont un potentiel de production de NO plus élevé que les souches des autres espèces. Ce test a également révélé que certaines souches de SCN sont capables de former de l’oxymyoglobine à partir de la metmyoglobine.Cette étude a permis de mettre en évidence l’implication de la NOS dans la production de NO chez S. xylosus et la capacité de formation de nitrosomyoglobine chez d’autres souches de SCN isolées de viandeCoagulase Negative Staphylococci (CNS) are usually isolated from meat and meat products. In meat products, S. xylosus and S. carnosus are the only CNS species used as meat starter cultures. In these products, nitrate and nitrite are used as additives where they contribute to the development of the typical red coloration. Staphylococci contribute to the development and stability of colour through their nitrate reductase activity that reduces nitrate to nitrite. Nitrite is chemically reduced to nitric oxide (NO) which is able to bind the ferrous-heme iron to form the stable bright red nitrosomyoglobin pigment. However, the safety regarding the use of these additives on meat products has been questioned as nitrite is able to form N-nitroso compounds such as nitrosamines. Some bacteria are able to synthesize NO by nitric oxide synthase (NOS). The nos gene was identified in a collection of CNS isolated from meat. The NOS sequence is well conserved between species. NO production has been investigated based on the formation of red myoglobin derivatives from metmyoglobin such as oxymyoglobin and nitrosomyoglobin. Subsequently, the nitrosoheme was extracted from nitrosomyoglobin. Nitrosoheme formation was reduced under limited oxygenated condition while it was abolished under aerobic condition in a S. xylosus C2a nos deleted mutant. Moreover, NOS is involved in oxidative stress resistance in S. xylosus C2a. In order to determine the potential of NO production among other strains of S. xylosus and other CNS species, their potential to form nitrosomyoglobin was evaluated. Nitrosomyoglobin formation is strain- and species-dependent. This assay has also revealed that several CNS strains are able to form oxymyoglobin from metmyoglobin.This study has demonstrated NOS-dependent NO production in S. xylosus and the ability of CNS isolated from meat to form nitrosomyoglobin
39
Cho, Seung-Hak. "Epidemiologische und molekulare Untersuchungen zur Biofilmbildung in Staphylococcus epidermidis und Staphylococcus aureus." Doctoral thesis, [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96419127X.
40
Juodžentytė, Renalda. "Staphylococcus aureus ir Staphylococcus pseudintermedius išskyrimas iš gyvūnų augintinių ir jų savininkų." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140305_133603-55635.
Анотація:
Šio darbo tikslas - Staphylococcus aureus ir Staphylococcus pseudintermedius išskyrimas iš gyvūnų augintinių, jų savininkų ir antimikrobinių medžiagų atsparumo nustatymas.
Darbo uždaviniai:
1. Išskirti stafilokokus iš gyvūnų augintinių.
2. Išskirti stafilokokus iš gyvūnų augintinių savininkų.
3. Identifikuoti koaguliazei teigiamus stafilokokus.
4. Įvertinti įvairių veiksnių įtaka šunų nosies ertmės ir tiesiosios žarnos mikroflorai.
5. Įvertinti įvairių veiksnių įtaka gyvūnų augintinių savininkų nosies ertmės mikroflorai.
6. Nustatyti atsparumą antimikrobinėms medžiagoms.
Iš viso paimti 123 mėginiai, iš jų 82 mėginiai paimti iš šunų laikomų namuose ir lauke, ir 41 mėginys iš jų savininkų. Mėginiai mikrobiologiniam tyrimui buvo imami į transportines terpes TRANSWAB® (naudojama pernešimo terpė aerobams ir anaerobams išskirti (Amies, Liofilchem, Italija)).
Mikroorganizmų išskirta iš 37 (30,1 proc.) mėginių. Po vieną mikroorganizmų rūšį nustatyta 33 (89,1 proc.) mėginiuose. Po dvi mikroorganizmų rūšis (mišri infekcija), nustatyta 4 (10,9 proc.) mėginiuose.
Iš šunų nosies ertmės ir tiesiosios žarnos paimto 41 mėginio mikroorganizmai buvo išskirti iš 27 (59,3 proc.). Staphylococcus pseudintermedius sudarė 32,4 proc. išskirtų mikroorganizmų, Staphylococcus aureus – 12,2 proc., Bacillus spp. – 14,7 proc.
Iš šunų savinikų nosies ertmės paimto 41 mėginio mikroorganizmai buvo išskirti iš 16 (55,9 proc.) mėginių. Staphylococcus aureus sudarė 36,5 proc. išskirtų mikroorganizmų... [toliau žr. visą tekstą]The objective of the research: Staphylococcus aureus and Staphylococcus pseudintermedius isolation from a pet and their owners, and determine the resistance of isolates to antimicrobial agent. Tasks of the research: 1. To isolate staphylococci from pet. 2. To isolate staphylococci from pet owners. 3. To identify coagulase-positive staphylococci. 4. Evaluate the influence of canine nasal and rectal flora. 5. Evaluate the influence of the pet owners nasal cavity flora. 6. To determine the resistance of isolates to antimicrobial agent. 41 samples of dogs and 41 from humans were investigated. Total take 123 samples, including 82 samples were taken from dogs kept in the home and outdoors, and 41 samples of their owners. Samples for microbiological analysis were collected in transport medium TRANSWAB ® (used to transport medium for aerobes and anaerobes release (Amies, Liofilchem, Italy)). Microorganisms were identified in 37 (30.1 percent.) samples. Single type of microorganisms were identified in 33 (89.1 percent) samples. Two types of microorganisms (mixed infection) were identified in 4 (10.9 percent) samples. In dogs, nasal and rectal were taken 41 samples. Microorganisms were identified in 27 (59.3 percent) samples. Staphylococcus pseudintermedius accounted 32.4 percent of identified microorganisms, Staphylococcus aureus – 12.2 percent, Bacillus spp. – 14.7 percent. Dogs owners nasal were taken 41 samples. Microorganisms were identified in 16 (55.9 percent) samples... [to full text]
41
BARRIERE, CHARLOTTE. "Caracterisation des superoxyde dismutases et catalases de staphylococcus xylosus et staphylococcus carnosus." Clermont-Ferrand 2, 2001. http://www.theses.fr/2001CLF22282.
Анотація:
Staphylococcus xylosus et staphylococcus carnosus sont deux especes a gram-positif, anaerobies facultatives, utilisees comme ferments dans les saucissons. Ils modulent la nature et le niveau des composes volatils issus de l'oxydation des acides gras. Leurs superoxyde dismutases (sods) et leurs catalases ont ete caracterisees afin de determiner leur pouvoir antioxydant. S. Xylosus c2a possede une seule sod proche des mnsods. Le gene codant (sod) a ete clone et sequence et deux promoteurs fonctionnels ont ete identifies en amont. L'expression du gene sod, etudiee a l'aide de fusions transcriptionnelles sod-lach, n'est pas modifiee par le paraquat ou le manganese, mais, elle est induite en phase stationnaire dans un milieu complexe. L'analyse du mutant sod, revele un role protecteur de la sod face a un stress oxydant. La sequence nucleotidique du gene kata de s. Xylosus c2a, codant une catalase proche des catalases monofonctionnelles, a ete determinee. L'expression du gene kata, etudiee a l'aide d'une fusion transcriptionnelle kata-lach, est induite, en phase stationnaire, par l'oxygene et le peroxyde d'hydrogene (h 2o 2). Elle est reprimee par le fer et surtout par le manganese. La presence d'une boite perr putative en amont du gene suggere une possible regulation par perr. Le mutant kata garde une activite catalase elevee revelant que kata n'est pas la principale catalase chez s. Xylosus c2a. En revanche, kata est essentiel pour une resistance optimale a l'h 2o 2 s. Xylosus c2a inhibe l'oxydation de l'acide linoleique. Sa sod et sa catalase kata contribuent a limiter cette oxydation. S. Carnosus 833 semble posseder une seule sod et une seule catalase dont les conditions de synthese semblent proches de celles de s. Xylosus c2a. La sod de s. Carnosus 833 presente de fortes similitudes de sequence avec celle de s. Xylosus c2a.
42
Messad, Nourreddine. "Staphylococcus aureus colonisant / Staphylococcus aureus infectant dans le modèle du pied diabétique." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT063/document.
Анотація:
Staphylococcus aureus est l’un des principaux agents étiologiques des infections suppuratives superficielles et profondes ainsi que des syndromes liés à l’action de toxines. Paradoxalement, cette bactérie est un agent commensal qui est présent sur la peau ainsi que dans les cavités nasales notamment. Cela permet de considérer cette bactérie comme un organisme colonisant commensale. Les bases génétiques expliquant la différence entre une bactérie pathogène et une bactérie commensale reste inconnues. En utilisant la technique Optical Maps sur des souches de S. aureus isolées de plaies de pieds diabétiques avec différents niveau de virulence, nous avons pu montrer l’existence d’un prophage insérés dans le génome des souches colonisantes et absent des souches infectantes. Le phage, nommé ROSA, est localisé dans un hotspot d’insertion de phage NM2. Il est aussi localisé en amont du locus isd qui est requis pour l’assimilation du fer essentiel à la bactérie dans sa phase pathogène. Le phage ROSA inactive la voie isd en dérégulant l’activité du régulateur transcriptionnel majeur Fur en absence de fer. Il réduit aussi la virulence de ces souches sur les 2 modèles de virulence (Le ver C. elegans et le Zebrafish). L’expulsion du phage ROSA restaure la régulation du locus isd par Fur et la production de sidérophores en absence de Fer, la formation du biofilm et la virulence des souches. La mutation du gène Fur nous a permis de déduire que le phage ROSA affectait les bactéries de manière indépendante de Fur. Enfin, nous avons étudié la prévalence des souches colonisantes sur les plaies de pieds diabétiques. Nous avons observé que 20% des souches présentait l’insertion ROSA et 89% appartenait au complexe clonal CC8. Les souches colonisantes, avec leur niveau bas de virulence, devraient faire l’objet de détection dans le but de rationnaliser l’utilisation des antibiotiques et ainsi lutter contre l’apparition de bactéries multirésistantes aux antibiotiquesStaphylococcus aureus is an opportunistic bacterium capable of causing a wide range of severe diseases when it gains access to underlying tissues. Paradoxically, this causative pathogen is a common inhabitant of the skin microflora and colonizes the nares and other human mucosa, and as such, may be considered as a commensal colonizing organism. The genetic basis for the differences in pathogenic/colonizing potential is unknown. By performing optical maps comparisons of a collection of S. aureus strains of defined virulence potential isolated from diabetic foot ulcers at different stages, we brought to light a prophage present in colonizing-causing bacteria. The phage, namely ROSA, was localized in a hotspot region NM2 near the locus isd, the main iron surface determinant that transport iron across the bacterial wall. It induces a deregulation of the activity of the transcriptional regulator Fur involving the biofilm formation of the bacteria in response to low iron environment. It reduced also significantly the virulence of the strain in two in vivo models (the nematode C. elegans and the zebrafish). The expulsion of the phage restored the regulation of the locus isd, the siderophore production, the biofilm formation and the virulence of the strain. The mutation of the fur gene within the colonizing strain enabled us to determine that the phage ROSA affect the the bacteria in a Fur-independent manner. Finally we determined the prevalence of these colonizing strains in skin and soft tissue infections (diabetic foot ulcers). We observed that 20% (39/195) of the strains harboured this insertion and 89% belonged to the clonal complex CC8. This colonizing strain by its low virulence potential must be detected in the aim to contribute to a sounder use of antibiotic treatment, an important point in front of the increase of multidrug resistant bacteria
43
Oliveira, Hanna Lara da Cruz Dinéas de. "Avaliação da ação de biocidas e papaína na formação de biofilmes em amostras hospitalares de Staphylococcus epidermidis e Staphylococcus haemolyticus resistentes a meticilina." Niterói, 2017. https://app.uff.br/riuff/handle/1/3271.
Анотація:
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Os estafilococos coagulase negativos emergem como importantes patógenos nosocomiais, frequentemente isolados em bacteremias humanas, fato intimamente relacionado com o aumento do uso de dispositivos médicos ao longo dos últimos anos. Sua capacidade de aderir a superfícies poliméricas e produzir biofilmes constitui o principal fator de virulência associado a estes dispositivos. A fim de minimizar esta possibilidade, antissépticos são largamente utilizados para desinfecção de pele e mucosas na rotina hospitalar, no entanto, tem-se observado uma diminuição da susceptibilidade bacteriana a estes agentes. A diminuição da susceptibilidade dos microrganismos a antissépticos, associados a sua capacidade de formar biofilmes tem elevado a morbidade, mortalidade, período de internação e os custos relativos ao cuidado com a saúde. No estudo aqui apresentado, foram analisadas 81 cepas de Staphylococcus epidermidis resistentes a meticilina (MRSE) e 55 cepas de Staphylococcus haemolyticus resistentes a meticilina (MRSHa), todas resistentes a meticilina, isoladas de pacientes internados em hospital Universitário localizado na cidade de Niterói-RJ nos anos de 2008 e 2010. A determinação do perfil de susceptibilidade aos biocidas triclosan, clorexidina e cloreto de benzalcônio mostrou que frente ao triclosan, as amostras apresentaram as menores taxas de susceptibilidade bacteriana. Papaína não apresentou atividade antibacteriana. Entretanto, foi capaz de reduzir expressivamente a formação de biofilme (p<0,06) em ambas as espécies, mostrando-se a mais eficiente entre os produtos analisados. Foi capaz também de desintegrar biofilmes maduros formados por Staphylococcus epidermidis. Os biocidas não levaram à redução significante de biofilmes, exceto a clorexidina, que foi capaz de reduzir a formação do biofilme pelas MRSE. Foi possível verificar que cepas de MRSHa tratadas com cloreto de benzalcônio têm 40% menos probabilidade de formar biofilme se comparada às tratadas com triclosan e clorexidina. A análise estatística nos mostrou que a expressão do gene qacA/B influenciou significativamente a formação de biofilme e confirmou a relação existente entre os valores de concentração mínima inibitória (CMI) e a formação de biofilme (p< 0,001)
Coagulase negative staphylococci have emerged as important nosocomial pathogens, commonly isolated in human bacteremia, a fact closely related to the increased use of medical devices over the last few years. Its ability to adhere to polymer surfaces and produce biofilms is the main virulence factor associated with these devices. To minimize this possibility, antiseptics are widely used for disinfection of skin and mucosa in routine hospital, however, there has been an increase in bacterial resistance to these agents. Decreased susceptibility of microorganisms to antiseptics, associated with its ability to form biofilms has high morbidity, mortality, length of stay and costs related to health care. In the study presented here, we analyzed 81 strains of methicillin-resistant Staphylococcus epidermidis (MRSE) and 55 strains of methicillin-resistant Staphylococcus haemolyticus (MRSHa), all meticillin- resistant, isolated from patients hospitalized at University Hospital in the city of Niterói, Rio de Janeiro in 2008 and 2010. The determination of the susceptibility profile of biocides triclosan, chlorhexidine and benzalkonium chloride demonstrated that front of triclosan, the strains have the biggest rates of bacterial susceptibility. Papain showed no antibacterial activity. However, it was able to significantly reduce biofilm formation (p <0.06) in both species, being the most efficient among the analyzed products. It was also able to degrade established biofilms formed by Staphylococcus epidermidis. Biocides showed no significant reduction of biofilms, except chlorhexidine, which was able to reduce biofilm formation by MRSE. We noticed that strains MRSHa treated with benzalkonium chloride are 40% less likely to form biofilm compared to those treated with chlorhexidine and triclosan. Statistical analysis showed that the gene expression qacA/B was significantly influential to biofilm formation and confirmed positive relationship between the values of MIC and biofilm formation (p <0.001)
44
Greco, Carey Anne. "Growth and Biofilm Formation by Staphylococcus Epidermidis and Other Relevant Contaminant Bacteria During Storage of Platelet Concentrates." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20253.
Анотація:
Coagulase negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet concentrates (PCs), and have been implicated in severe and fatal transfusion reactions. Of this group, Staphylococcus epidermidis is most frequently identified. The preliminary objective of this thesis was to confirm that S. epidermidis could form biofilms under platelet storage conditions. This was achieved using a modified crystal violet staining assay to detect plastic-adherent bacterial cells and examination of attachment processes by scanning electron microscopy. A collection of CoNS isolated from PCs obtained from reportedly healthy donors was then assessed for biofilm-forming potential at the genetic and phenotypic level. Despite the presumable commensal origin of these isolates, a high proportion of S. epidermidis strains displayed a biofilm positive phenotype.
The threat of S. epidermidis biofilm formation during platelet storage identified herein signifies that any alterations made to platelet storage protocols should be evaluated with consideration of this risk. The advent of platelet additive solutions (PASs) as an alternative to plasma for PC storage provides a relevant example, since little is known about the effect of PAS on contaminant bacteria, and vice versa. Growth and biofilm formation by S. epidermidis and the Gram-negative bacterium Serratia liquefaciens were measured in PAS- or plasma-PCs over 5 days, simulating standard platelet storage conditions, after initial inoculation with low, clinically relevant bacterial concentrations. Assays for platelet quality were performed simultaneously. Only S. liquefaciens exhibited a slower doubling time in plasma-PCs than in PAS-PCs. Biofilm formation by both species was reduced during storage in PAS-PCs, increasing bacteria availability for detection. Although S. liquefaciens adversely affected platelet quality in both media, S. epidermidis contamination did not. Ultimately, culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs.
Lastly, since formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, it was postulated that biofilm formation by contaminant bacteria could be abrogated by receptor shielding. Methoxypoly(ethylene glycol) was applied to covalently modify the platelet surface using a process termed ‘PEGylation’. It is herein demonstrated that PEGylation of PCs inoculated with S. epidermidis results in significantly reduced bacterial binding and biofilm formation during platelet storage.
45
Calander, Ann-Marie. "Proteases in staphylococcal arthritis /." Göteborg : Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, Göteborg University, 2007. http://hdl.handle.net/2077/2584.
46
Pourkomailian, B. "Osmoregulation in Staphylococcus aureus." Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.593300.
Анотація:
Osmoregulation in Staphylococcus aureus has been studied. Glycine betaine was found to act as an osmoprotectant by stimulating specific growth rate and salt tolerance of osmotically stressed S. aureus cells. The accumulation of this compatible solute was accomplished via two constitutive Na+ dependant transport systems, a high-affinity system (Km = 3μM; Vmax = 26nmol. min-1 mg total protein-1) and a low-affinity system (Km = 133μM; Vmax = 155 nmol. min-1 mg total protein-1). The high-affinity system is specific for glycine betaine and its activity is not greatly stimulated by osmotic pressure. The low-affinity sytem transports proline and proline analogues and its activity is stimulated by increases in external osmolarity. Proline transport is achieved via two similar systems. Through transposon mutagenesis it was demonstrated that the low-affinity glycine betaine transport system and the low-affinity proline transport system are the same system. The low-affinity system is the major system responsible for the accumulation of glycine betaine. This is the more important system for the osmoregulation strategy of S. aureus. All three transport systems have been demonstrated to be subject to feedback regulation. The internal compatible solute concentration dictates the level of activity of the transport systems. A mutant has been isolated that lacks the low-affinity system and the high-affinity proline transport system.
47
Peacock, Sharon. "Staphylococcal fibronectin-binding proteins." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275055.
48
Worthington, Tony. "Serodiagnosis of staphylococcal sepsis." Thesis, Aston University, 2000. http://publications.aston.ac.uk/12356/.
Анотація:
The coagulase-negative staphylococci are the most frequent cause of sepsis associated with indwelling intravascular catheters. Current microbiological investigations to support the diagnosis of catheter-related sepsis (CRS) include the culture of blood and catheter tips, however positive results may reflect specimen contamination, or colonisation of the catheter rather than true sepsis. Previous serological approaches to assist in the diagnosis of CRS based on cellular staphylococcal antigens have been of limited value. In this current study, the serodiagnostic potential of an exocellular antigen produced by 7 strains of coagulase-negative staphylococci cultured in brain heart infusion broth was investigated. Antigenic material isolated by gel permeation from liquid culture was characterised by immunological techniques and chemical analysis. Characterisation of the exocellular antigen revealed a novel glycerophosphoglycolipid, termed lipid S. which shared antigenic determinants with lipoteichoic acid, but differed by comprising a glycerophosphate chain length of only 6 units. In addition, lipid S was immunologically distinct from diphosphatidyl glycerol, a constituent cell membrane phospho lipid. An indirect enzyme linked immunosorbent assay (ELISA) based on lipid S was subsequently developed and used to determine serum antibody levels (IgM and IgG) in 67 patients with CRS due to staphylococci, and 67 patients with a central venous catheter (CVC) in situ who exhibited no evidence of sepsis. The sensitivity and specificity of the lipid S IgG ELISA was 75% and 90% respectively whilst the IgM assay had sensitivity and specificity of 52% and 85%. The addition of GullSORereagent to the EL1SA procedure to remove competing serum IgG and rheumatoid factor did not significantly improve the performance of the IgM assay. The serological response in serial serum samples of 13 patients with CRS due to staphylococci was investigated. Elevated levels of antibody were detected at an early stage of infection, prior to the isolation of microorganisms by standard culture methods, and before the clinical presentation of sepsis in 3 patients. The lipid S ELISA was later optimised and a rapid 4-hour assay developed for the serodiagnosis of CRS. Serum IgG levels were determined in 40 patients with CRS due to staphylococci and 40 patients with a CVC in situ who exhibited no evidence of sepsis. The sensitivity and specificity of the rapid IgG assay was 70% and 100% respectively. Elevated serum antibody levels in patients with endocarditis, prosthetic joint infection and pyogenic spondylodiscitis due to Gram-positive cocci were also detected with the lipid S ELISA suggesting that the assay may facilitate the diagnosis of these infections. Unexpected increased levels of anti-lipid S IgG in 31% of control patients with sciatica suggested a possible microbial aetiology of this condition. Further investigation of some of these patients by culture of microdiscectomy tissue removed at operation, revealed the presence of low-virulent microorganisms in 37% of patients of which Propionibacterium aeries accounted for 85% of the positive culture isolates. The results suggested a previously unrecognised association between P. acnes and sciatica, which may have implications for the future management of the condition.
49
Lucet, Jean-Christophe. "Epidémiologie de Staphylococcus aureus." Paris 11, 2004. http://www.theses.fr/2004PA114817.
Анотація:
Ce travail a cherché à établir l'importance du réservoir méconnu des porteurs de Staphylococccus aureus résistant à la méticilline (SARM) dans l'épidémiologie hospitalière de cette bactérie multirésistante aux antibiotiques, la plus fréquente en France. Il montre au travers d'enquêtes prospectives, que la prévalence et l'incidence du SARM sont beaucoup plus elévées que ne laissent penser les surveillances basées sur des prélèvements à visée clinique. Il établit des facteurs de risque de portage de SARM, et suggère enfin que la stratégie de dépistage et précautions " contact " est efficace. Le contrôle de la dissémination manuportée du SARM doit inclure une stratégie raisonnée de dépistage des porteursOur research aimed to determine the significance of unknown carriage of methicillin-resistant Staphylococcus aureus in the epidemiology of this multiply-resistant strains in the hospital setting. Through prospective observational studies of MRSA carriage, we demonstrated that incidence and prevalence of MRSA at hospital admission are much higher than that estimated by clinical isolates only. We established parameters associated with MRSA carriage, and suggested that active surveillance screening and contact precautions are valuable in the ICU setting. Controlling the hospital spread of MRSA should include a judicious strategy for screening MRSA
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Zhang, Lihong. "Studies on protein Sbi in Staphylococcus aureus /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5780-7.pdf.