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1
Pryor, Shona Marie. "Bovine mastitis and ecology of Streptococcus uberis." The University of Waikato, 2008. http://hdl.handle.net/10289/2580.
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Bovine mastitis caused by Streptococcus uberis is a common problem in pasture-based dairying systems. This study examines both the ecology of S. uberis and infection of the bovine mammary gland on a New Zealand dairy farm. Initially, the REP-PCR strain typing method was developed and the potential of MALDI-TOF mass spectrometry evaluated as a strain typing method. While strain-specific mass spectra were obtained with MALDI-TOF mass spectrometry, the irreproducibility of spectra was its major downfall. With further work, this rapid method could be very useful for strain typing S. uberis on a large scale. Using optimised REP-PCR and anchored typing methods, multiple S. uberis strains were isolated and strain typed from the dairy environment, including farm races and paddocks, faeces, teat skin, the cow body and from intramammary infections. High strain diversity was observed in all sampled locations; however, some strains were found at more than one site, suggesting transmission may occur between the environment and cows. The most likely means of S. uberis distribution throughout the dairy farm was via excretion with faeces and, although not all cow faeces contained this pathogen, the gastrointestinal tract of some cows appeared to be colonised by specific strains, resulting in persistent shedding of this bacteria in the faeces. Infection of the mammary gland is likely to occur through contamination of the teat skin with highly diverse environmental strains of S. uberis. However, only one or two strains are generally found in milk from mastitis cases, suggesting that, although infection may arise from a random or opportunistic event, a strain selection process may take place. Intramammary challenge with multiple strains of S. uberis revealed that selection of a single infective strain can occur within the mammary gland. The predominance of one strain over others may be related to production of virulence factors allowing enhanced ability to establish in the gland and evade the immune response, or due to direct competition between strains through the production of antimicrobial factors such as bacteriocins. In addition to strain-specific factors, the individual cow and quarter response may play an important role in the development of infection and selection of the infective strain. Using results from this study, a model of S. uberis strain transmission has been proposed, which includes potential mechanisms of infection and persistence of S. uberis within the mammary gland.
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Gilchrist, Tamara Louise. "Genotypic and phenotypic characterisation of Streptococcus uberis." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2938/.
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Streptococcus uberis is an important bovine mastitis pathogen, which places a significant financial burden upon the dairy industry. Determining the genetic diversity of a collection of field isolates and the mechanisms by which S. uberis colonises the host were the general aims of this project, in particular the determination of the basis for bacterial persistence despite antibacterial therapy. Multi-locus sequence typing identified high levels of recombination within the population, but also a single dominant clonal complex which comprised nearly all sequence types which were isolated from more than one animal. The dominant clonal complex also comprised isolates, derived, however, from both persistent and non-persistent infections, but RAPD typing demonstrated that these isolates can differ in genetic composition elsewhere in the genome. Whole genome sequencing of additional S. uberis isolates confirmed that despite significant homology between much of these genomes, novel genetic material was commonly obtained by phage insertion and horizontal gene transfer. Isolates with identical housekeeping sequences are thus highly likely to differ in their virulence gene repertoires. In this study, the potential for differentiating S. uberis isolates based instead upon protein profiles derived from mass spectrometry of disrupted whole cells was therefore also explored. Differentiation between small numbers of isolates was achieved after optimisation of this protocol, however, discriminatory ability and reproducibility were somewhat compromised when the technique was scaled up to analyse 50 Italian isolates. During the period of study, profile differences between persistent and non-persistent isolates could not be explored. Basic methods were thus also utilised in an attempt to identify factors which promoted bacterial survival in vitro; and a defined medium, representative of the udder environment, was optimised for this purpose. The use of this medium permitted the demonstration that S. uberis was reliant upon magnesium and manganese for proliferation and that, interestingly, the absence of iron did not inhibit bacterial growth. It was also shown that S. uberis had the ability to directly utilise casein, identifying a potential alternative pathway for the acquisition of essential nutrients from nutritionally-limited environments. It was also observed that to a limited extent S. uberis seemed to produce a siderophore. Although this remains to be confirmed, it may correlate with the observation that iron, although not essential for proliferation, improved the growth rate of the bacterium. It was also notable that most novel genes, identified from S. uberis genome sequences, exhibited functions for nutrient metabolism, demonstrating that flexibility in nutrient acquisition is central to the ability of the bacteria to adapt, permitting survival in vastly different environments. The use of the defined medium also demonstrated that S. uberis was able to form biofilms; this ability being variable depending on the growth conditions used and the isolate studied. Most significantly, under conditions representative of the mammary gland, there was an apparent trend for high levels of biofilm formation to correlate with isolates from persistent infections. Biofilm formation by Staphylococcus aureus is considered to be pivotal to the development of chronic mastitis, thus, biofilms may similarly play a role in S. uberis persistence. In an attempt to identify the molecular basis for S. uberis biofilm formation, genes with homology to those of the intercellular adhesion (ica) operon, well described for their involvement in Staphylococcus epidermidis and S. aureus biofilm formation, were identified in the genome sequence of S. uberis 0140J. A targeted mutagenesis protocol was optimised to ‘knock out’ these genes and observe the subsequent effects of these mutations on biofilm formation. During the course of this study, two of these potential biofilm genes (hasA and SUB 0809) were deleted from the S. uberis 0140J chromosome. Surprisingly, deletion of these genes did not retard subsequent biofilm formation, but instead biofilm formation was dramatically improved in the mutant strains. Characterisation of mastitis-causing S. uberis strains and a detailed understanding of the pathogenicity of the organism are required to further the development of a successful vaccine. The research presented in this thesis has increased the knowledge of these important research objectives and optimised techniques which will allow further advancement of knowledge in this field.
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Crowley, Rebecca Clare. "Molecular analysis of biofilm growth in streptococcus uberis." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488613.
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Streptococcus uberis is a major causative agent of bovine intramammary infections worldwide. S. uberis infections can persist for several months and resistance to antibiotic therapies has been observed. At present, the failure to bring S. uberis infections under control has been linked to the current lack of information with regards to S. uberis pathogenesis.
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Rapier, Christopher David. "Characterisation of the plasmin receptor of Streptococcus uberis." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268981.
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Hossain, Muhammad Maqsud. "Bioinformatic analysis of Streptococcus uberis genes and genomes." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/37355/.
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Streptococcus uberis is a Gram-positive, catalase-negative member of the family Streptococcaceae and is an important environmental pathogen primarily responsible for a significant amount of bovine intramammary infections. This thesis describes the sequencing and comparison of multiple strains from clinical and sub-clinical infections. Following de novo assembly, these are compared to the single reference strain (0140J). The assemblies of strains sequenced with two technologies (Illumina and SOLiD) were compared. From these assemblies, annotation allowed the comparison of gene content, the pan and core genomes and gene gain/loss of coding sequences associated with clustered regularly interspaced short palindromic repeats (CRISPRs), prophage and bacteriocin production. Identification of sequence variants allowed identification of highly conserved and highly variant genes. Inferred intraspecies and interspecies (host-S. uberis) protein-protein interaction networks revealed pathways of bovine proteins enriched with potentially interacting pathogen proteins. These identified known and predicted pathways and also novel interaction partners. This was the first “whole-genome” comparison of multiple S. uberis strains isolated from clinical vs non-clinical intramammary infections including the type virulent vs non-virulent strains. These data allowed the first insight into potential evolutionary forces behind virulence differences.
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Denham, Emma Louise. "Molecular characterisation of lipoprotein processing in Streptococcus uberis." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/30496.
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Streptococcus uberis is a common cause of bovine mastitis and the lipoprotein MtuA has been shown to be essential for growth in milk and virulence. The enzymes responsible for processing lipoproteins in other Gram positive bacteria are lipoprotein diacylglyceryl transferase (Lgt) which acts to anchor lipoproteins to the membrane and lipoprotein signal peptidase (Lsp) which cleaves the signal peptide. S. uberis mutants containing lesions in lgt and lsp uncovered several novel phenotypes. A number of additional proteins were shown to be present in extracellular fractions prepared from lgt- and lgt-/lsp- mutants when compared to the equivalent fraction prepared from wild type bacteria. Atypical processing of MtuA and other lipoproteins within the signal peptide was shown to occur, indicating the presence of an activity capable of shaving such proteins from the membrane in the absence of Lgt and Lsp activity. MtuA was shown to be released into the extracellular space by Wetern blot; the size closely resembled that of wild type protein in both the lgt- and lgt-/lsp- mutants. A metallopeptidase that can be inhibited by phosphoramidon and metal ion chelating agents may be responsible for the activity that results in these proteins being alternatively processed. MtuA in the lsp- mutant had a molecular weight that corresponded to full length MtuA and remained localised in the membrane as seen in the wild type. During late log phase a second form of MtuA with a lower molecular weight was detected. A mutant containing insertions in both lsp and the gene encoding the S. uberis homologue to the Enterococcus faecalis was studied. Enhanced expression of pheromone (eep) suggested that this metallopeptidase was also able to cleave the signal peptide of MtuA.
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Wirawan, Ruth E., and n/a. "An investigation into the antimicrobial repertoire of Streptococcus uberis." University of Otago. Department of Microbiology & Immunology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070312.142108.
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Streptococcus uberis, an environmental organism also associated with dairy animals, is a common and persistent cause of bovine mastitis. New approaches to control these infections need to be identified. One such strategy may be the application of bacteriocins; proteinaceous antimicrobials elaborated by bacteria that typically inhibit the growth of strains closely related to the producer organism. The well-characterized lactococcal bacteriocin nisin is the active ingredient in two commercial products currently in use for the prevention of mastitis. However, reports of resistance development have prompted the investigation of alternative bacteriocins to be used in conjunction with nisin in 'bacteriocin cocktails' designed to have more comprehensive inhibitory activity against mastitis pathogens. The bacteriocins of gram-positive bacteria have been divided into four distinct classes: (I) lantibiotics, (II) non-lantibiotic peptides, (III) large proteins, and (IV) circular peptides.
Although it has been known for more than twenty years that S. uberis commonly produce bacteriocin-like inhibitory substances (BLIS), none had been characterised prior to the present study. The first step in the current investigation was a survey of the BLIS activities of a set of fifteen S. uberis and S. bovis strains against a set of standard indicators as well as common gram-positive mastitis pathogens. Additional tests using a deferred antagonism agar plate-based assay showed that some of the BLIS activities were heat-sensitive and their production was influenced by the presence of either blood or a fermentable carbohydrate source in the test medium. On the basis of the results obtained from these tests it became apparent that S. uberis and S. bovis may commonly produce more than a single inhibitory agent.
S. uberis 42 became the focus of this study because (a) it had broad inhibitory activity against mastitis-associated bacteria, (b) it did not display cross-resistance to nisin, and (c) from the preliminary screening results it appeared to produce both heat-stable and heat-labile inhibitory agents. Acid extracts of S. uberis 42 cells yielded inhibitory activity that, when fractionated by reversed-phase HPLC, yielded a peptide of 3029 Da. Although this peptide was blocked to Edman degradation at position 2, following propanethiol-modification a 20-amino acid sequence was obtained. Degenerate primers to lantibiotic biosynthesis gene homologs were used to initiate inverse PCR and primer walking, ultimately yielding a 15-kb contiguous sequence encompassing 11 genes typical of those involved in lantibiotic synthesis, regulation and immunity. Due to the close similarities to nisin of the S. uberis 42 lantibiotic precursor (78%), and the organisation and composition of the locus, this inhibitor was named nisin U. Nucleotide sequences homologous to insertion sequences were detected in the vicinity of the nisin U locus, and indicate a possible mechanism of acquisition of this locus by S. uberis. The locus was detected in ten other S. uberis, and also in two S. agalactiae and two S. thoraltensis strains, and in one S. porcinus and one S. pluranimalium strain. The amino acid sequences of some of these differed in one or two amino acids, and these variants were named nisin U2 and nisin U3 accordingly. Nisin U, the two nisin U variants, and nisin A exhibited cross-immunity (i.e. all of the producer strains were insensitive to each form of nisin) and cross-inducibility (i.e. all of the producer strains displayed enhanced production when exposed to each form of nisin).
Nisin U did not contribute to the entire spectrum of inhibitory activity of S. uberis 42. Freeze thaw extracts of S. uberis 42 agar cultures yielded heat-labile inhibitory activity that was inhibitory to L. lactis A5, a producer of nisin Z. Subsequent purification by cation-exchange chromatography, gel filtration, and reversed-phase HPLC yielded a peptide of mass 7048 Da, which was resistant to Edman degradation. Digestion with chymotrypsin released an 819 Da peptide fragment of sequence NH₂-KAQAVIW-COOH. Tn916 mutagenesis of S. uberis 42 enabled the identification of the genetic locus of the inhibitor, comprising six genes potentially involved in its biosynthesis and immunity. The detection of a pair of flanking 159-bp direct repeats indicates possible acquisition of the locus by 'long target duplication'. The inhibitor was inferred to be a circular peptide, on the basis of its behaviour to Edman degradation, and by comparison of its locus with that of other circular bacteriocins. On the basis that the purified peptide appears to induce lysis in sensitive bacteria, although by an as-yet unidentified mechanism, the inhibitor was named uberolysin. The uberolysin structural gene was detected in eight other strains of S. uberis, however not all of these appeared to be producing active inhibitor.
No bacteriocins closely resembling the two reported in this thesis have been demonstrated previously to be produced by members of the genus Streptococcus. The remarkable diversity in the structures, activity spectra and basic modes of action of these two bacteriocins produced by a single strain of S. uberis, combined with the observation of apparent greater heterogeneity in properties of a preliminary sampling of BLIS-producing strains, indicates that these bacteria may be an important source of novel antimicrobials of potential value for the treatment of mixed bacterial infections and for minimising potential resistance development.
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Copsey, Sarah Denise. "Characterisation of a metal-ion dependent repressor in Streptococcus uberis." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426229.
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Khan, Izhar-ul-Haq. "Identification and further characterization of Streptococcus uberis and Streptococcus parauberis isolated from bovine milk samples." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964881799.
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Vinha, Rita Bronze. "Utilização intramamária de benzilpenicilina procaínica na terapêutica de mamites por Streptococcus uberis." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2020. http://hdl.handle.net/10400.5/20242.
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Dissertação de Mestrado Integrado em Medicina VeterináriaStreptococcus uberis é um agente etiológico de mamites, ubiquitário no ambiente das vacas sendo considerado ambiental, porém com alguma componente contagiosa. Atualmente, é considerado um dos agentes mais preocupantes, que produz mamites tanto subclínicas como clínicas graves e, frequentemente, associadas a contagens de células somáticas (CCS) elevadas. Estas infeções acarretam uma grande dificuldade no processo de cura e as medidas clássicas de controlo de mamites não se demonstram eficazes contra este agente, pois dispõe de vários fatores de virulência. Deste modo, o estudo apresentado visa avaliar a eficácia de várias terapêuticas à base de benzilpenicilina procaínica intramamária (IMM), com diferentes durações, e a vantagem de associar um antibiótico sistémico, neste caso a ampicilina. De forma a proceder a este trabalho, desde dia 16 de setembro de 2019 até 18 de fevereiro de 2020, foram recolhidas amostras de leite de vacas com sinais de mamite, tais como quartos mamários edemaciados e/ou tumefactos e/ou alterações no leite, de várias explorações leiteiras pertencentes à Proleite. Todas as vacas identificadas microbiologicamente com S. uberis foram submetidas a um dos três protocolos terapêuticos em estudo: benzilpenicilina procaínica IMM durante sete dias, uma terapia combinada com ampicilina intramuscular durante cinco dias e outra apenas com administração IMM num período de cinco dias. Assim, através das taxas de cura clínica, analisadas pela CCS, foi percetível que tanto a terapia combinada (57,1%) como o tratamento IMM de sete dias (54,5%) proporcionaram uma taxa de cura razoável, ao contrário da terapêutica IMM de cinco dias (25%). A fase produtiva do animal poderá ter tido alguma influência nas taxas de cura atingidas, já que se verificou que apenas 42,1% das vacas multíparas atingiu a cura clínica. Também a duração destas infeções poderá ter sido limitante, uma vez que somente 35,7% das vacas com IIM prolongada apresentaram cura clínica. Após a aplicação de qualquer protocolo terapêutico foi visível uma diminuição nas células somáticas presentes no leite das vacas afetadas, todavia estas mantêm-se em valores elevados. Quanto à epidemiologia, confirmou-se que S. uberis é bastante prevalente (5,8%), está associado a elevados valores de células somáticas e foi, também, percetível que 77,3% destas mamites ocorrem num período próximo da secagem, que os animais com uma fase produtiva mais avançada são mais suscetíveis (86,4%) e que são normalmente infeções já subclínicas e de longa duração (63,5%).
ABSTRACT - Intramammary use of procaine benzylpenicillin in the treatment of Streptococcus uberis mastitis - Streptococcus uberis is an etiologic agent of mastitis, that is ubiquitous in the environment of cows, so it is considered as an environmental agent, however with a contagious component. Currently, it is considered one of the most worrying agents, which produces both subclinical and severe clinical mastitis, frequently associated with high somatic cell counts (SCC). These infections are known by the problematic healing process and most of the classic control measures do not demonstrate any use against this agent, because it can exhibit several virulence factors. In this way, the study presented aims to evaluate the effectiveness of various therapies based on intramammary (IMM) procaine benzylpenicillin, with different durations and to know the advantage of associating a systemic antibiotic, in this case ampicillin. In order to proceed with the study, from September 16, 2019 to February 18, 2020, milk samples from cows with signs of mastitis, such as swollen teats and/or changes in milk, from various types of dairy farms belonging to Proleite, were collected. All infections microbiologically identified with S. uberis were subjected to one of the three therapeutic protocols under study: procaine benzylpenicillin IMM for seven days, a combination therapy with intramuscular ampicillin for five days and another one with only IMM administration for five days. Thus, trough the clinical cure rates, analyzed by the SCC, it was shown that both, the combination therapy (57,1%) and the seven-day IMM treatment (54,5%), had a reasonable cure rate, in contrast to the five-day IMM therapy (25%). The animal’s productive stage may have some influence on the cure rates achieved, which has been verified because only 42,1% of the multiparous cows achieved the clinical cure. The duration of these infections may also have been a limitation, since only 35,7% of the cows with prolonged IMI showed a clinical cure. After the application of any therapeutic protocol, a reduction in the somatic cells present in the milk of the affected cows was detected, however these remain in high values. Regarding epidemiology, it was confirmed that it is a very prevalent agent (5,8%) and that is associated with high values of somatic cells. It was also noticeable that 77,3% of the S. uberis mastitis occurred close to the drying period, that animals with a more advanced productive stage are more susceptible (86,4%) and that these infections are mostly already subclinical and long lasting (63,5%).
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Collado, Gimbert Rosa. "Desenvolupament d’una vacuna contra la mamitis bovina causada per Streptococcus uberis." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/670298.
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Bovine mastitis caused by Streptococcus uberis is a major problem in the dairy industry worldwide. Despite of that, there is no vaccine commercial available against it. Therefore, the objectives of this doctoral thesis are framed in phases 1 and 2 of the development process of a new vaccine against bovine mastitis caused by S. uberisLa mamitis bovina causada per Streptococcus uberis és un problema de gran importància en les explotacions lleteres bovines a nivell mundial i en l’actualitat no existeix cap vacuna comercial que hagi demostrat ser eficaç per combatre aquesta patologia. Els objectius de la present tesi doctoral s’emmarquen en les fases 1 i 2 del procés de desenvolupament d’una nova vacuna contra la mamitis bovina causada per S. uberis
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Jones, Catherine Louise. "Molecular characterisation of an essential membrane transporter system of 'Streptococcus uberis'." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424206.
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Swanson, Kara M., and n/a. "The bovine mammary gland immune response to Streptococcus uberis and its bacteriocins." University of Otago. Department of Microbiology & Immunology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080407.112302.
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Bovine mastitis is one of the most costly dairy-based diseases worldwide. Streptococcus uberis is a prevalent causative organism of mastitis and resides naturally in the environment of the dairy cow making prevention of the disease difficult. New strategies need to be developed to control this pathogen. However, a fundamental understanding of the complex relationships that exist between the cow, the pathogen and the environment are required in order to advance the development of prevention strategies. Microarray technology was used to evaluate the complex transcriptional changes which occur in the bovine mammary gland following the onset of clinical S. uberis mastitis. A 22,000 bovine cDNA microarray indicated that S. uberis mastitis led to the up-regulation of 1,283 genes and the down-regulation of 1,237 genes by greater than 1.5 fold. Gene ontology analysis demonstrated that S. uberis mastitis was typically associated with the up-regulation of genes that are involved in the immune response and homeostasis and a down-regulation of genes involved in lipid metabolism. Quantitative real-time analyses for a selection of genes associated with the immune response validated the microarray data. Mammary epithelial cell cultures did not show an increase in the expression of any of these immune factors in response to the same S. uberis strain used to induce clinical mastitis. This indicates that the expression of immune-related genes by mammary epithelial cells may be initiated by host factors and not S. uberis.
The application of bacteriocins, proteinaceous antimicrobials produced by bacteria which typically inhibit the same or closely-related species to that of the producer organism, has been suggested as one possible approach in the control of mastitis. S. uberis have been previously found to commonly produce bacteriocin-like inhibitory substances (BLIS). The BLIS activities of a set of fifteen S. uberis and S. bovis strains were assessed. The results confirmed the prolific and varied nature of BLIS production by S. uberis and S. bovis and also indicated that these strains may commonly produce more than one inhibitory agent. This survey of BLIS production led to the detection and characterisation of a novel circular bacteriocin, uberolysin, produced by S. uberis strains 233 and 42. The structural gene of uberolysin was subsequently identified in nine (64%) of the fifteen test strains.
Multiplex PCR analysis showed that 93% of 158 New Zealand S. uberis isolates contained the structural genes of at least one of the four known S. uberis bacteriocins (uberolysin, nisin U, ubericin A and ubericin 63). However, no apparent direct association was identified between any one of these bacteriocin-related loci and apparent ability to cause mastitis on New Zealand dairy farms. The uberolysin structural gene was detected in 91% of the isolates and this widespread distribution prompted the advancement and evaluation of a potential role for uberolysin in immunomodulation within the bovine mammary gland. Two different preparations of uberolysin were found to have different stimulatory effects on monocytes, neutrophils and epithelial cells. The less highly purified preparation appeared to diminish the production of TNF-α by monocytes in the presence of a bacterial stimulus and to decrease neutrophil phagocytosis. By contrast, the relatively more highly purified preparation of uberolysin itself induced a significant immune response by monocytes. Consistent with this, the purer preparation of uberolysin induced an increase in C3, IL-1β, IL-6, IL-8, the β-defensin LAP, the acute-phase protein MSAA, the calcium-binding protein S100A12 and TLR2 by quantitative real-time analysis.
Although currently only two S. uberis bacteriocins (uberolysin and nisin U) have been fully characterised, the present study has shown that this species may be an important source of novel antimicrobials. Furthermore, bacteriocin production by S. uberis may have an immunomodulation role within the mammary gland. A better understanding of the complex immune response initiated at the onset of clinical S. uberis mastitis and of the role that bacteriocins have in S. uberis pathogenesis may lead to development of improved strategies to combat this disease.
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Thomson, Caroline M. A. "Induction of resistance to phagocytic killing of Streptococcus uberis by bovine neutrophils." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259889.
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Achard, Adeline. "Bases biochimiques et génétiques de la résistance aux macrolides et antibiotiques apparentés chez Streptococcus agalactiae et Streptococcus uberis." Caen, 2007. http://www.theses.fr/2007CAEN2007.
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L’utilisation des antibiotiques du groupe des macrolides et apparentés (MLS) en médecine humaine et vétérinaire a conduit à l’émergence de bactéries résistantes. Cette émergence est préoccupante chez les streptocoques. Les travaux réalisés ont permis de mettre en évidence l’émergence de résistances par inactivation des MLS chez deux espèces du genre Streptococcus : Streptococcus agalactiae et Streptococcus uberis. La première concerne une résistance aux lincosamides chez S. Agalactiae et S. Uberis, et la seconde une résistance à la spiramycine (macrolide à 16 atomes) chez S. Uberis. La résistance aux lincosamides est due à la présence d’une nucléotidyltransférase codée par le gène lnu(C). Ce gène est porté par un transposon mobilisable, MTnLnu, chez la souche clinique S. Agalactiae UCN36 et par un plasmide transférable chez la souche vétérinaire S. Uberis 88. MTnLnu est le premier transposon mobilisable rapporté chez les streptocoques et est mobilisé par le transposon conjugatif Tn916. L’origine de transfert a été localisée dans le gène lnu(C). La résistance à la spiramycine de la souche vétérinaire S. Uberis 74 est liée à la présence des gènes rdmC-like et mph(B). Ces deux gènes codent respectivement une enzyme apparentée à la famille des alpha/bêta hydrolases et une phosphotransférase connue pour inactiver les macrolides à 14, 15, et 16 atomes chez E. Coli. Des résultats préliminaires laissent présager une action combinée des deux enzymes sur la spiramycineThe therapeutic use of macrolides and related antibiotics (MLS ) has led to the emergence of resistant bacteria. Resistance of streptococci to these antibiotics is alarming, because of their wide use in human and veterinary environments. In this study, we report the emergence of MLS resistance by inactivation in two species of Streptococcus: Streptococcus agalactiae and Streptococcus uberis. A human isolate of S. Agalactiae was shown to inactivate lincosamide whereas an animal isolate of S. Uberis, inactivated spiramycin (a 16- membered ring macrolide). The lincosamide resistance was due to a nucleotidyltransferase encoded by a new lnu(C) gene. The gene was localized on a mobilizable transposon, MTnLnu in S. Agalactiae UCN36, and on a transferable plasmid in the veterinary strain S. Uberis 88. MTnLnu is the first mobilizable transposon reported in streptococci and could be mobilized by the conjugative transposon Tn916. The spiramycin resistance of the veterinary strain S. Uberis 74 was related to the presence of a rdmC-like and the mph(B) genes. These genes encoded an enzyme belonging to the alpha/beta hydrolases family and a phosphotransferase known to inactivate 14, 15 and 16-membered macrolides in E. Coli, respectively. Preliminary results suggested a combined action of these two enzymes on spiramycin
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Ricardo, Patrícia Manuel Quintas. "Clínica e cirurgia de espécies pecuárias: estudo dos ambientais em mastites clínicas." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/14004.
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Do presente relatório constam a descrição das atividades desenvolvidas no âmbito do estágio curricular do Mestrado Integrado de Medicina Veterinária, assim como uma revisão bibliográfica referente às mastites bovinas, nomeadamente as de origem ambiental. Por fim, é apresentado um trabalho experimental desenvolvido, cujo objetivo foi estudar os agentes ambientais responsáveis por mastites clínicas com visível descoloração do leite.
Atualmente, as mastites bovinas representam o maior desafio da indústria leiteira e são, não só uma preocupação entre produtores, mas também entre os consumidores que são cada vez mais exigentes com a qualidade dos produtos lácteos.
Ao longo das últimas décadas, os agentes contagiosos têm vindo a perder importância para os agentes ambientais, sendo estes apontados como os principais responsáveis pela incidência de mastites clínicas.
O carácter adaptativo dos agentes maioritários ambientais, nomeadamente Escherichia coli e Streptococcus uberis, é referido por vários autores e parece estar evidente no trabalho experimental conduzido; Abstract:
Clinic and surgery of livestock species: a study of environmental agents in clinical mastitis
This report contains the description of the activities carried out under the traineeship of Master of Veterinary Medicine, as well as a literature review related to bovine mastitis, particularly those on environmental origin. Finally, an experimental work aimed to study the environmental agents responsible for clinical mastitis with visible discoloration of milk is presented.
Currently, bovine mastitis presents the greatest challenge on dairy industry and is not only a concern among producers but also among consumers who are increasingly demanding hight quality of dairy products.
Over the past decades, infectious agents have been losing importance to environmental agents, which are pointed out as the main responsible for the incidence of clinical mastitis.
The adaptive nature of the majority environmental agents, including Escherichia coli and Streptococcus uberis, is mentioned by several authors and seems to be evident in the experimental work here conducted.
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Czabanska, Anna [Verfasser]. "Immunochemical investigations of the cell envelope components isolated from Streptococcus uberis / Anna Czabanska." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2014. http://d-nb.info/1047790920/34.
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Barker, Timothy Richard. "A study of mastitis in dairy herds with particular reference to Streptococcus uberis." Thesis, University of Glasgow, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302001.
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Smith, Amanda Jane. "The identification of genes required for the growth of Streptococcus uberis in milk." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428160.
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Grant, Raymond G. "The role of the bovine mammary gland in immunological responses to Streptococcus uberis." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261337.
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Rato, Márcia Alexandra Gonçalves. "Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2011. http://hdl.handle.net/10362/7501.
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Dissertação para obtenção do Grau de Doutor em BiologiaStreptococcus agalactiae (Group B Streptococcus - GBS), Streptococcus dysgalactiae subsp. dysgalactiae (Group C Streptococcus - GCS) and Streptococcus uberis are relevant mastitis pathogens, a highly prevalent and costly disease in the dairy industry due to antibiotherapy and loss in milk production. However, molecular characterization of field isolates of Streptococcus spp. occurring in Portugal was not known prior to our studies and is important to improve therapeutic and disease control programs. The aims of this study were the identification of strain molecular features, and the evaluation of antimicrobial drug resistance patterns of S. agalactiae (n=60), S. dysgalactiae subsp. dysgalactiae (n=18) and S. uberis (n=30) collected from bovine subclinical mastitis between 2002/2003 in Portugal. Additionally, two S. dysgalactiae subsp. dysgalactiae strains associated with invasive disease(one collected from cattle and the other from a human), and six Streptococcus dysgalactiae subsp. equisimilis (group C or group G Streptococcus - GCS/GGS) strains from human infection were included in the study, for comparative purposes. Genotypic relationships were identified using pulsed-field gel electrophoresis (PFGE)/BioNumerics, S. agalactiae and S. uberis multi-locus sequence typing (MLST), macrolide and tetracycline resistance gene profiling, S. agalactiae molecular serotyping, virulence gene profiling, PCR-amplification for screening presence of specific genes and subsequent sequencing for phylogenetic analysis, and reverse transcriptase-PCR (RT-PCR) for gene expression analysis of selected genes. Also, a custom-designed microarray containing 220 virulence genes of the human pathogen Streptococcus pyogenes (Group A Streptococcus - GAS) was used to test bovine GCS S. dysgalactiae subsp. dysgalactiae and human GCS/GGS S.dysgalactiae subsp. equisimilis. Antimicrobial resistance was assessed by disk diffusion against penicillin, gentamicin, streptomycin, amoxicillin-clavulanic acid, cefazolin, cefoperazone,rifaximin, erythromycin, pirlimycin, tetracycline, vancomycin, chloramphenicol and the macrolide lincosamide resistance phenotypes (cMLSB, iMLSB, M, L). Among S. uberis three PFGE clonal groups (defined by at least 80% similarity) comprised almost half of total isolates, and 50% of GBS isolates were included in four major clonal groups (all farm-associated), which is indicative of a contagious route of transmission between animals. The occurrence of PFGE patterns sharing >82.8% and 100% similarity among S. dysgalactiae subsp. dysgalactiae isolates collected from different farms suggests an environmental source for this pathogen in our case. By MLST, we observed that all S. uberis sequence types (ST) were found to be novel (n=14), representing novel genomic backgrounds for this pathogen. Among GBS only three MLST lineages (ST-2, ST-23, and ST-61/ST-554) were detected revealing little heterogeneity among our bovine GBS collection. Five new cpsD-cpsE-cpsF sequences of the cps locus (encoding the capsular polysaccharide) were detected in >70% of the bovine GBS, which may represent new serotypes.
Fundação para a Ciência e a Tecnologia - Doctoral Project (SFRH/BD/32513/2006)
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Jiang, Min. "Molecular characterization of Streptococcus uberis CAMP factor, lactoferrin binding protein and their upstream genes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq24025.pdf.
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Watt, Catherine Judy. "The epidemiology of intramammary infection in dairy cows, with particular reference to Streptococcus uberis." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325614.
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Tassi, Riccardo. "Response to intramammary challenge with putatively host-adapted and non-adapted strains of Streptococcus uberis in cattle." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15910.
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Streptococcus uberis is an important cause of intramammary infection in dairy cattle. Strains of S. uberis appear to differ in their ability to cause disease based on previous epidemiological studies. We explored the pathogenicity of 2 strains of S. uberis, where one strain represented a putatively host-adapted type based on its ability to cause persistent infection and to spread from cow to cow in a lactating herd. This type was part of a clonal complex that is commonly associated with bovine mastitis. The other strain, which was isolated from a transient infection in a single animal in the same herd and did not belong to any known clonal complex, was selected as putatively non-adapted type. Cows (6 per strain) were experimentally challenged in a single hind quarter and the adjacent hind quarter was used as mock challenged control quarter. Both strains showed an equal ability grow in milk of challenge animals in vitro. All cows that were challenged with the putatively host-adapted strain developed clinical signs of mastitis, including fever and milk yield depression as well as elevated somatic cell count due to influx of polymorphonuclear leucocytes and lymphocytes. The cytokine response followed a specific order, with an increase in IL-1β, IL-6 and IL-8 levels at the time of first SCC elevation, followed by an increase in IL-10, IL-12p40 and TNF-α levels approximately 6 h later. In 4 of 6 animals, IL-17A was detected in milk between 57 and 168 h post challenge. The increase in IL-17A levels coincided with inversion of the pre-challenge CD4+:CD8+ T lymphocyte ratio, and was observed from 96 h post challenge. This was followed by normalisation of the CD4+:CD8+ ratio due to continued increase of the CD8+ concentration up to 312 h post challenge. Spontaneous resolution of infection was observed in 5 animals and coincided with a measurable IL-17A response in 4 animals, suggesting that IL-17 may be involved in the resolution of intramammary infection. To explore the mechanism of action of IL-17A we stimulated bovine PMN and bovine blood derived macrophages with recombinant IL-17A in vitro. IL-17A enhanced the killing ability of phagocyte toward the challenge strain. With the exception of minor elevation of IL-8 levels, no clinical, cytological or immunological response was detected in quarters challenged with the non-adapted strain. The observed strain specific pathogenicity was consistent across animals, implying that it is determined by pathogen factors rather than host factors. We further studied in vitro possible mechanisms involved in the differences observed between the two strains such as ability to adhere to the mammary epithelial cells, ability to resist to killing by phagocytes and ability to form biofilm. The adapted strain FSL Z1-048 showed an increased ability to adhere to the epithelial cells and an increase ability to resist to killing of monocyte derived macrophages. These mechanisms thus could potentially explain the in vivo observations.
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Kitt, Andrew John. "The auxotrophic nature of Streptococcus uberis : the acquisition of essential amino acids from plasmin hydrolysed bovine caseins." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265715.
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Orsi, Alessandra Módena. "Capacidade de formação de biofilme e resistência aos antimicrobianos de Staphylococcus aureus e Streptococcus uberis causadores de mastite bovina." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/10/10135/tde-02052017-123925/.
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Staphylococcus aureus e Streptococcus uberis são dois patógenos causadores mastite bovina que podem apresentar capacidade de produção de biofilme, o que pode resultar em infecções intramamárias crônicas, menor resposta à terapia, redução de produção de leite e maior risco de descarte das vacas infectadas. Os objetivos deste estudo foram avaliar a: 1) capacidade de formação de biofilme de S. aureus e S. uberis isolados de vacas com mastite clínica (MC) e subclínica (MSC); 2) sensibilidade in vitro e a multirresistência destes agentes a antimicrobianos selecionados (n=12); 3) associação entre a capacidade de formação de biofilme e resistência aos antimicrobianos de S. aureus e S. uberis. Um total de 197 cepas S. aureus e 128 S. uberis foram isoladas a partir de amostras de leite de vacas com MSC e MC, oriundas de 24 rebanhos. Os isolados de S. aureus e S. uberis foram avaliados quanto a capacidade de formação de biofilme pelo método??? e a sensibilidade in vitro aos antimicrobianos foi determinada pela técnica de disco difusão em ágar. A capacidade de formação de biofilme foi classificada em 4 categorias: forte, moderado, fraco e não formador de biofilme. Do total de cepas avaliadas, S. aureus (54,8%) e S. uberis (52,9%) apresentaram capacidade de formação de biofilme (forte, moderado ou fraco). Entre os isolados de S. aureus formadores de biofilme, a frequência de distribuição dos isolados foi de 19,3% na categoria forte, 18,8% moderado, e 16,7% na categoria fraco. Para os isolados de S. uberis, a frequência de distribuição entre as categorias de formação de biofilme foi 17,6% forte, 25,2% moderado, 17,6% fraco. Dentre as cepas de S. aureus isoladas de casos de MC, 55,8% foram classificados como forte formador de biofilme, enquanto 7,6% das cepas isoladas de MSC apresentaram capacidade de formação de biofilme. Todos os isolados de S. uberis (n=30; 100%) provenientes de MC apresentaram capacidade de formação de biofilme na categoria moderado. Quanto à sensibilidade aos antimicrobianos, os isolados de S. aureus apresentaram resistência à penicilina (92,9%), ampicilina (50,8%) e tetraciclina (18,3%); e os isolados de S. uberis apresentaram resistência à penicilina (86,5%), oxacilina (85,5%), tetraciclina (37,5%). Os isolados de S. aureus apresentaram maior chance de resistência aos antimicrobianos ampicilina, tetraciclina e ceftiofur que S. uberis. Em conclusão, S. aureus e S. uberis apresentam elevada capacidade de produção de biofilme, mas não houve interação entre a característica de multirresistência e formação de biofilme. Isolados de S. aureus e S. uberis foram altamente resistentes aos antimicrobianos das classes de beta-lactâmicos e tetraciclinas.Staphylococcus aureus and Streptococcus uberis are both mastitis causing pathogens that can present ability to produce biofilm, which can result in chronic intramammary infection, reduced response to the therapy, reduction of milk yield, and greater risk of cows\' culling. The objectives of this study were to evaluate the: 1) biofilm-forming capacity of S. aureus and S. uberis isolated from clinical (CM) and subclinical mastitis (SCM); in vitro sensibility and multi-resistance of these agents to the antimicrobials; 3) association between the biofilm-forming capacity and antimicrobial resistance. A total of 197 S. aureus and 128 S. uberis were isolated from milk samples collected from cows with SCM and CM from 24 dairy herds. The biofilm-forming ability were classified in 4 categories: strong, moderate, weak, and non-biofilm producers. Of all isolates evaluated, S. aureus (54.8%) and S. uberis (52.9%) presented biofilm-forming ability (strong, moderate or weak). Among the biofilm-forming isolates, the frequency of distribution of S. aureus was 19.3% for the strong, 18.8% for the moderate, and 16.7% for the weak categories. For the S. uberis isolates, the frequency of distribution among the biofilm-forming categories was 17.6% strong, 25.2% moderate, and 17.6% weak. In relation to the mastitis presentation form, the strong biofilm-forming category had 55.8% of S. aureus isolates from CM cases; and among all biofilm-forming categories, the strong category was the one with the higher number of isolates of S. aureus (n=43; 19,2%). All S. uberis isolates (n=30; 100%) from CM presented moderate biofilm-forming ability. In relation to the antimicrobial susceptibility, the isolates of S. aureus were resistant to penicillin (92.9%), ampicillin (50.8%) and tetracycline (18.3%); and the isolates of S. uberis presented resistance to penicillin (86.5%), oxacillin (85.5%) and tetracycline (37.5%). The isolates of S. aureus and S. uberis, S. aureus had higher odds to be resistant to ampicillin, tetracycline and ceftiofur than S. uberis. In conclusion, S. aureus and S. uberis presented high ability of production of biofilm, but there was no interaction between multi-resistance and biofilm production ability. Isolates of S. aureus and S. uberis were highly resistant to antimicrobials of the class of beta lactams and tetracycline.
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Moraes, Rayane Amaral da Silva. "Frequência de Streptococcus uberis em amostras de leite de rebanhos bovinos de Minas Gerais e identificação de seus fatores de virulência." Universidade Federal de Minas Gerais, 2010. http://hdl.handle.net/1843/SMOC-9HHN9E.
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Bovine mastitis causes the major economic losses in Brazilian dairy herds, and Streptococcus uberis is an important cause of this disease. Currently, the role of virulence factors of this pathogen in the interaction with the host has been the subject of research, in order to develop new strategies for prevention and control of bovine mastitis. Given the increasing importance of S. uberis in milk production chain in Brazil, in this work the identification of S. uberis was made in milk samples from Minas Gerais herds, using the PCR technique with the extraction of genomic DNA directly from milk. In 23 (9.2%) of 250 milk samples analyzed the presence of S. uberis was detected. The presence of genes pauA and sua, which respectively encode the virulence factors PauA and SUAM, was verified in 28 samples of S. uberis from different Minas Gerais southern region herds. These samples were also tested for antimicrobial susceptibility. pauA gene was detected in 22 (78.57%) of 28 samples, and the gene sua was found in 19 (67.86%) samples. All samples were sensitive to Cephalothin and Florfenicol, but a high degree of resistance to Tetracycline was found.A mastite bovina é responsável pelas maiores perdas econômicas na pecuária leiteira brasileira, sendo o Streptococcus uberis um importante causador dessa enfermidade. Atualmente, o papel dos fatores de virulência desse agente na interação com o hospedeiro vem sendo alvo de pesquisas, no intuito do desenvolvimento de novas estratégias de prevenção e controle da mastite bovina. Tendo em vista a crescente importância do S. uberis na cadeia produtiva do leite no Brasil, neste trabalho foi feita a identificação de S. uberis em amostras de leite oriundas de rebanhos de várias regiões do estado de Minas Gerais, utilizando-se a técnica de PCR, com extração de DNA genômico diretamente do leite. Em 23 (9,2%) das 250 amostras de leite analisadas foi detectada a presença de S. uberis. Buscou-se ainda detectar a presença dos genes pauA e sua, que codificam respectivamente os fatores de virulência PauA e SUAM, em 28 amostras de S. uberis provenientes de diversos rebanhos bovinos da região sul de Minas Gerais. Estas foram submetidas também a testes de susceptibilidade frente a antimicrobianos. O gene pauA foi detectado em 22 (78,57%) das 28 amostras, já para o gene sua, 19 (67,86%) foram positivas. Quanto à susceptibilidade a antimicrobianos, todas as amostras mostraram-se sensíveis à Cefalotina e ao Florfenicol, porém encontrou-se um alto grau de resistência à Tetraciclina.
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Renard, Laurent. "Modélisation de la relation pharmacodynamie-pharmacocinétique en antibiothérapie vétérinaire : modélisation pharmacodynamique in vitro d'un antibiotique "temps-dépendant", la spiramycine, et d'un antibiotique "concentration-dépendant", la colistine; stimulation de la relation pharmacocinétique-pharmacodynamie de la colistine vis-à vis de Escherichia coli chez le veau, application de la modèlisation pharmacocinétique/pharmacodynamique au cas de mammites expérimentales à Staphylococcus aureus et à Streptococcus uberis chez la vache laitière." Limoges, 1994. http://www.theses.fr/1994LIMO303C.
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Rambeaud, Magdalena. "Dynamics of leukocytes and cytokines during experimentally-induced Streptococcus uberis mastitis." 2002. http://etd.utk.edu/2002/RambeaudMagdalena.pdf.
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Thesis (M.S.)--University of Tennessee, Knoxville, 2002.Title from title page screen (viewed Feb. 26, 2003). Thesis advisor: Stephen P. Oliver. Document formatted into pages (xii, 105 p. : ill.(some col.)). Vita. Includes bibliographical references (p. 83-101).
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Vales, Marta Sofia Morais. "Epidemiological Evaluation of Mastitis Caused by Streptococcus Agalactiae and Streptococcus Uberis in Four Dairy Herds in North of Portugal." Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/74949.
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Khan, Izhar-ul-Haq [Verfasser]. "Identification and further characterization of Streptococcus uberis and Streptococcus parauberis isolated from bovine milk samples / submitted by Izhar ul-haq Khan." 2002. http://d-nb.info/964881799/34.
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Yu-Hsin, Chang, and 張予馨. "Development of PCR primers and microarrays for the detection of Staphylococcus aureus、Staphylococcus saprophyticus、Staphylococcus epidermidis、Staphylococcus haemolyticus、Streptococcus agalactiae、Streptococcus uberis and Streptococcus bovis using heat shoc." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18829275241866666629.
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碩士弘光科技大學
生物產業研究所
97
Abstract Staphylococcus spp. including S. aureus, S. saprophyticus, S. epidermidis, S. haemolyticus and S. xylosus, etc. are important pathogenic bacteria, Diagnosis of these staphylococcus species isolated from food poisoning cases and clinical samples are important. Recently, studies revealed that heat shock protein gene, hsp60, hsp10 and hsp10-hsp60 (IGR) sequences can be used as a target gene for the identification of Staphylococcus spp. Therefore, the purpose of this study is to design of species specific PCR primers, i.e., S.aurF/R, S.sap-F/R, S.epi-F/R, and S.hae-F/R, respectively, these on the heat shock protein gene (hsp) sequences. For Staphylococcus genus, universal primers, were also developed to amplify the hsp genes of Staphylococcus genus. Using S.aurF/R, S.sap-F/R, S.epi-F/R, and S.hae-F/R primer sets, bacterial species other than S. aureus, S. saprophyticus, S. epidermidis, S. haemolyticus, including other Staphylococcus. Spp. would not generate any false positive reaction. The detection limit were N × 103 cfu/ml. Such methods can be used for bacteria identification, rapid diagnosis, and these primers may be used on probes into biochip system. Staphylococcus aureus, Streptococcus agalactiae, Strept. uberis, and Strept. bovis, etc., are common pathogens which may cause Mastitis in dairy herds. Conventional methods for the detection of these bacterial species are time consuming and laborious. Thus, the development of rapid and reliable methods for the detection of these bacterial species is also important. In this study, we also designed the PCR primer sets, SAU3/SAU4, SAG3/SAG4, SUB3/SUB4 and SBO3/SBO4 from the heat shock protein gene, i.e., hsp70, hsp40, and hsp10, for the specific detection of Strep. agalactiae、Strep. uberis、Strep. bovis and S. aureus, respectively. Using SAU3/SAU4, SAG3/SAG4, SUB3/SUB4 and SBO3/SBO4 primer sets, bacterial species other than S. aureus、Strep. agalactiae、Strep. uberis、Strep. bovis, including other Strept. spp. would not generate any false positive reaction. As these PCR primer sets were used for multiplex PCR detection of target cells in pure culture, the detection limit was N × 103 cfu/ml, the detection limit were N × 104 and N × 100 cfu/ml milk depending on whereas the target cells were pre-enriched 10 hr, or not. Thus, the PCR and the multiplex PCR system so established offer a rapid method for detection of bovine mastitis pathogenic bacteria. Such method may be useful for the veterinary inspection agency and the dairy industry.
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Porfírio, Afonso Almeida. "Charactezation of Virulence and Antibiotic Resistence Genetic Markers in Streptococcus Agalactiae and Strepococcus Uberis Causing Bovine Mastitis." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/69045.
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Porfírio, Afonso Almeida. "Charactezation of Virulence and Antibiotic Resistence Genetic Markers in Streptococcus Agalactiae and Strepococcus Uberis Causing Bovine Mastitis." Master's thesis, 2013. https://hdl.handle.net/10216/69045.
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Wan-Yu, Pai, and 白宛玉. "Development and application of PCR primers for Streptococcus agalactiae, Strep. uberis and Strep. bovis using heat shock protein gene." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/87831659244078089418.
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碩士弘光科技大學
生物科技研究所
95
Staphylococcus aureus, pathogenic E. coli, Streptococcus agalactiae, Strepto. uberis, and Strepto. bovis, etc., are common pathogens which may cause Mastitis in dairy herds. Conventional methods for the detection of these bacterial species need the use of selection and differentiation medium followed by biochemical and serological identification steps. Such process is time consuming and laborious. Thus, the development of rapid and reliable methods for the detection of these bacterial species is important. In this study, we designed the PCR primer sets, SAG1/SAG2, SUB1/SUB2, and SBO1/SBO2 from the heat shock protein gene, i.e., HSP70, HSP40, and HSP10, for the specific detection of Strep. agalactiae、Strep. uberis、Strep. bovis, respectively. Using SAG1/SAG2, SUB1/SUB2, and SBO1/SBO2 primer sets, bacterial species other than Strep. agalactiae、Strep. uberis、Strep. bovis, including other Strept. spp. would not generate any false positive reaction. As those PCR primer sets were used for Conventional and Real-time PCR detection of target cells in milk, the detection limit were N × 103, and N × 100 CFU/ per ml milk if the target cells were without/with the pre-enrichment step for 10 hr, respectively. In this study, these PCR primer sets for the conventional and real-time PCR methods so established will offer a rapid and quantitative method for detection of bovine mastitis pathogenic bacteria. Such method can be used by government agency for animals disease monitoring and bovine farming industry.