Journal articles on the topic 'Minor and major bacterial pathogens'
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WHITE, L. J., Y. H. SCHUKKEN, T. J. G. M. LAM, G. F. MEDLEY, and M. J. CHAPPELL. "A multispecies model for the transmission and control of mastitis in dairy cows." Epidemiology and Infection 127, no. 3 (December 2001): 567–76. http://dx.doi.org/10.1017/s0950268801006100.
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Mastitis in dairy cows is a significant economic and animal welfare issue in the dairy industry. The bacterial pathogens responsible for infection of the mammary gland may be split into two main categories: major and minor pathogens. Infection with major pathogens generally results in clinical illness or strong inflammatory responses and reduced milk yields, whereas minor pathogen infection is usually subclinical. Previous investigations have considered the transmission of these pathogens independently. Experimental evidence has shown cross-protection between species of pathogens. In this study a mathematical model for the coupled transmission of major and minor pathogens along with their interaction via the host was developed in order to consider various methods for controlling the incidence of major pathogen infection. A stability analysis of the model equilibria provides explanations for observed phenomena and previous decoupled modelling results. This multispecies model structure has provided a basis for quantifying the extent of cross-protection between species and assessing possible control strategies against the disease.
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Miklas, Phillip N., Valerie Stone, Carlos A. Urrea, and James S. Beaver. "Specific Genomic Regions in Common Bean Condition Resistance to Multiple Pathogens." HortScience 32, no. 3 (June 1997): 451E—451. http://dx.doi.org/10.21273/hortsci.32.3.451e.
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A genetic linkage map of 170 RAPD markers mapped across 79 recombinant inbred lines (Dorado and XAN-176) reveal genomic regions that condition multiple disease resistance to fungal (Ashy Stem Blight—Macrophomina phaseolina), viral (bean golden mosaic virus—BGMV), and bacterial (common bacterial blight—Xanthomonas campestris pv. phaseoli) pathogens of common bean (Phaseolus vulgaris). A genomic site on linkage group US-1 had a major effect, explaining 18%, 34%, and 40% of the variation in phenotypic reaction to ashy stem blight, BGMV, and common bacterial blight disease, respectively. Adjacent to this region was a QTL conditioning 23% of the variation in reaction to another fungal pathogen, web blight (Thanatephorus cucumeris). A second genomic site on linkage group US-1 had minor affect on multiple resistance expression to the same fungal (15%), viral (15%), and bacterial (10%) pathogens. It is unknown whether these specific genomic regions represent a series of linked QTL affecting resistance to each disease separately or an individual locus with pleiotropic effect against all three pathogens.
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Bexiga, Ricardo, Mikko T. Koskinen, Jani Holopainen, Carla Carneiro, Helena Pereira, Kathryn A. Ellis, and Cristina L. Vilela. "Diagnosis of intramammary infection in samples yielding negative results or minor pathogens in conventional bacterial culturing." Journal of Dairy Research 78, no. 1 (December 7, 2010): 49–55. http://dx.doi.org/10.1017/s0022029910000725.
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Up to half of quarter milk samples submitted for mastitis diagnosis are culture-negative results or lead to identification of coagulase-negative staphylococci or Corynebacterium bovis in conventional culturing, the so-called minor pathogens. The interpretation and usefulness of these results in terms of udder and animal health management is limited, even though the amount of resources spent is relatively high. This work aimed to test two methods of analysis of milk samples with the goal of increasing detection of intramammary pathogens. In the first study, 783 milk samples were processed in duplicate: before and after freezing at −20°C for 24 h, using standard bacteriological techniques. There was a significant difference between the two methods with samples frozen for 24 h yielding significantly fewer Gram-positive catalase-positive cocci, Gram-negative bacilli, Gram-positive bacilli and significantly more samples leading to no growth, than samples before freezing. The number of samples yielding Gram-positive catalase-negative cocci was not significantly affected by freezing. In the second study, a real-time PCR-based test was performed on milk samples with an individual quarter somatic cell count above 500 000 cells/ml that were either negative (n=51 samples) or that led to the isolation of minor pathogens in culturing: Corynebacterium bovis (n=79 samples) or non-aureus staphylococci (NAS, n=32). A mastitis pathogen, beyond the result obtained with standard bacteriology, was detected on 47% of the no-growth samples, on 35% of the samples from which C. bovis had been isolated and on 25% of the samples from which NAS had been isolated. The most commonly detected major pathogen was Escherichia coli, followed by Streptococcus uberis, Arcanobacterium pyogenes/Peptoniphilus indolicus and Streptococcus dysgalactiae. These results suggest that simply freezing milk samples for 24 h does not increase the detection of intramammary bacteria in milk samples and therefore should not be recommended. However, use of the real-time PCR-based test may be useful in diagnosing intramammary infections when milk samples with high somatic cell counts are culture-negative or when culturing results in the detection of minor pathogens.
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Ulrich, Sebastian, and Frank Ebel. "Monoclonal Antibodies as Tools to Combat Fungal Infections." Journal of Fungi 6, no. 1 (February 4, 2020): 22. http://dx.doi.org/10.3390/jof6010022.
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Antibodies represent an important element in the adaptive immune response and a major tool to eliminate microbial pathogens. For many bacterial and viral infections, efficient vaccines exist, but not for fungal pathogens. For a long time, antibodies have been assumed to be of minor importance for a successful clearance of fungal infections; however this perception has been challenged by a large number of studies over the last three decades. In this review, we focus on the potential therapeutic and prophylactic use of monoclonal antibodies. Since systemic mycoses normally occur in severely immunocompromised patients, a passive immunization using monoclonal antibodies is a promising approach to directly attack the fungal pathogen and/or to activate and strengthen the residual antifungal immune response in these patients.
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Moran Losada, Patricia, Philippe Chouvarine, Marie Dorda, Silke Hedtfeld, Samira Mielke, Angela Schulz, Lutz Wiehlmann, and Burkhard Tümmler. "The cystic fibrosis lower airways microbial metagenome." ERJ Open Research 2, no. 2 (April 2016): 00096–2015. http://dx.doi.org/10.1183/23120541.00096-2015.
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Chronic airway infections determine most morbidity in people with cystic fibrosis (CF). Herein, we present unbiased quantitative data about the frequency and abundance of DNA viruses, archaea, bacteria, moulds and fungi in CF lower airways.Induced sputa were collected on several occasions from children, adolescents and adults with CF. Deep sputum metagenome sequencing identified, on average, approximately 10 DNA viruses or fungi and several hundred bacterial taxa.The metagenome of a CF patient was typically found to be made up of an individual signature of multiple, lowly abundant species superimposed by few disease-associated pathogens, such asPseudomonas aeruginosaandStaphylococcus aureus, as major components. The host-associated signatures ranged from inconspicuous polymicrobial communities in healthy subjects to low-complexity microbiomes dominated by the typical CF pathogens in patients with advanced lung disease. The DNA virus community in CF lungs mainly consisted of phages and occasionally of human pathogens, such as adeno- and herpesviruses. TheS. aureusandP. aeruginosapopulations were composed of one major and numerous minor clone types.The rare clones constitute a low copy genetic resource that could rapidly expand as a response to habitat alterations, such as antimicrobial chemotherapy or invasion of novel microbes.
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Sain, Bhawana, Vandana Sharma, Ashok Kumar Sharma, Rakesh Goyal, and Mukesh Sharma. "DALAFLOXACIN- ANTIBACTERIAL: A REVIEW." International Journal of Research -GRANTHAALAYAH 6, no. 1 (January 31, 2018): 91–101. http://dx.doi.org/10.29121/granthaalayah.v6.i1.2018.1597.
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Antibiotics (from ancient Greek αντιβιοτικά, antiviotika), also called antibacterials, are a type of antimicrobials drug used in the treatment and prevention of bacterial infections. Cellulitis is an infection that involves the outer layers of the skin. It is commonly caused by bacteria known as beta-hemolytic streptococcus or Staphylococcus aureus. You may experience pain, swelling, tenderness, warmth, and redness in the infected area. Complicate skin and soft tissue infections (SSTIs) are common for both outpatient and hospitalized patients and traditionally include various clinical symptoms ranging from minor superficial infections to necrotizing fasciitis with high rates of mortality. Delafloxacin (DLX) is a new FQ pending approval, which has shown a good in vitro and in vivo activity against major pathogens associated with ABSSSIs and CA-RTIs. It also shows good activity against a broad spectrum of microorganisms, including those resistant to other FQ, and stability against multiresistant strains.
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Kielak, Anna M., Mariana Silvia Cretoiu, Alexander V. Semenov, Søren J. Sørensen, and Jan Dirk van Elsas. "Bacterial Chitinolytic Communities Respond to Chitin and pH Alteration in Soil." Applied and Environmental Microbiology 79, no. 1 (October 26, 2012): 263–72. http://dx.doi.org/10.1128/aem.02546-12.
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ABSTRACTChitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA andchiAgenes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity ofchiAgene types in soil is enormous and (i) that differentchiAgene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one ofActinobacteriain the immediate response to the added chitin (based on 16S rRNA gene abundance andchiAgene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.
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Falade, Mofolusho O., and Benson Otarigho. "Characterization of potential drug targeting folate transporter proteins from Eukaryotic Pathogens." F1000Research 6 (July 13, 2017): 36. http://dx.doi.org/10.12688/f1000research.10561.2.
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Background: Medically important pathogens are responsible for the death of millions every year. For many of these pathogens, there are limited options for therapy and resistance to commonly used drugs is fast emerging. The availability of genome sequences of many eukaryotic microbes is providing critical biological information for understanding parasite biology and identifying new drug and vaccine targets. Methods: We developed automated search strategies in the Eukaryotic Pathogen Database Resources (EuPathDB) to construct a protein list and retrieve protein sequences of folate transporters encoded in the genomes of 200 eukaryotic microbes. The folate transporters were categorized according to features including mitochondrial localization, number of transmembrane helix, and protein sequence relatedness. Results: We identified 234 folate transporter proteins associated with 63 eukaryotic microbes including 48 protozoa, 13 fungi the others being algae and bacteria. Phylogenetic analysis placed 219 proteins into a major clade and 15 proteins into a minor clade. All the folate transporter sequences from the malaria parasite, Plasmodium, belonged to the major clade. The identified folate transporters include folate-binding protein YgfZ, folate/pteridine transporter, folate/biopterin transporter, reduced folate carrier family protein and folate/methotrexate transporter FT1. About 60% of the identified proteins are reported for the first time. Phylogeny computation shows the similarity of the proteins identified. Conclusion: These findings offer new possibilities for potential drug development targeting folate-salvage proteins in eukaryotic pathogens.
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Stocks, Claudia J., Minh-Duy Phan, Maud E. S. Achard, Nguyen Thi Khanh Nhu, Nicholas D. Condon, Jayde A. Gawthorne, Alvin W. Lo, et al. "UropathogenicEscherichia coliemploys both evasion and resistance to subvert innate immune-mediated zinc toxicity for dissemination." Proceedings of the National Academy of Sciences 116, no. 13 (March 7, 2019): 6341–50. http://dx.doi.org/10.1073/pnas.1820870116.
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Toll-like receptor (TLR)-inducible zinc toxicity is a recently described macrophage antimicrobial response used against bacterial pathogens. Here we investigated deployment of this pathway against uropathogenicEscherichia coli(UPEC), the major cause of urinary tract infections. Primary human macrophages subjected EC958, a representative strain of the globally disseminated multidrug-resistant UPEC ST131 clone, to zinc stress. We therefore used transposon-directed insertion site sequencing to identify the complete set of UPEC genes conferring protection against zinc toxicity. Surprisingly, zinc-susceptible EC958 mutants were not compromised for intramacrophage survival, whereas corresponding mutants in the nonpathogenicE. coliK-12 strain MG1655 displayed significantly reduced intracellular bacterial loads within human macrophages. To investigate whether the intramacrophage zinc stress response of EC958 reflected the response of only a subpopulation of bacteria, we generated and validated reporter systems as highly specific sensors of zinc stress. Using these tools we show that, in contrast to MG1655, the majority of intramacrophage EC958 evades the zinc toxicity response, enabling survival within these cells. In addition, EC958 has a higher tolerance to zinc than MG1655, with this likely being important for survival of the minor subset of UPEC cells exposed to innate immune-mediated zinc stress. Indeed, analysis of zinc stress reporter strains and zinc-sensitive mutants in an intraperitoneal challenge model in mice revealed that EC958 employs both evasion and resistance against zinc toxicity, enabling its dissemination to the liver and spleen. We thus demonstrate that a pathogen of global significance uses multiple mechanisms to effectively subvert innate immune-mediated zinc poisoning for systemic spread.
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OLIVER, S. P., B. E. GILLESPIE, M. J. LEWIS, T. L. INGLE, and H. H. DOWLEN. "Evaluation of Chlorhexidine as a Premilking Teat Disinfectant for the Prevention of Intramammary Infections During Lactation." Journal of Food Protection 57, no. 7 (July 1, 1994): 614–18. http://dx.doi.org/10.4315/0362-028x-57.7.614.
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A study was conducted for 15 months to evaluate efficacy of a 0.35% chlorhexidine teat dip as a premilking teat disinfectant based on reduction of naturally occurring new intramammary infections. Predipping was compared with a negative control using a split-udder experimental design. All teats were dipped after milking with the same 0.35% chlorhexidine teat dip. Most new major pathogen intramammary infections were caused by Streptococcus species, primarily Streptococcus uberis and Streptococcus equinus and gram-negative bacteria, primarily Escherichia coli. Percentage of quarters newly infected by major mastitis pathogens was 30.6% lower in mammary glands with teats predipped and postdipped in chlorhexidine than in mammary glands with teats postdipped only, and differences between treatment groups approached significance. New infections by coagulase-negative Staphylococcus species were significantly lower in mammary glands with teats predipped and postdipped than in mammary glands with teats postdipped only. When all mastitis pathogens were combined, percentage of quarters newly infected by major and minor mastitis pathogens was significantly lower in the predipped and postdipped group than in the postdipped only group. No statistical differences in incidence of clinical mastitis between treatment groups were observed. No chapping or irritation of teats was observed and no adverse effects were detected using chlorhexidine as a premilking and postmilking teat disinfectant. Results of this study suggest that premilking teat disinfection with chlorhexidine in association with good udder preparation and postmilking teat disinfection can further reduce the occurrence of new intramammary infections during lactation.
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Galfi, Annamaria, Miodrag Radinović, Dubravka Milanov, Sara Savić, Stanko Boboš, and Marija Pajić. "Lactoferrin and Immunoglobulin G Concentration in Bovine Milk from Cows with Subclinical Mastitis during the Late Lactation Period." Acta Scientiae Veterinariae 44, no. 1 (March 19, 2018): 6. http://dx.doi.org/10.22456/1679-9216.81097.
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Background: Lactoferrin and immunoglobulin G in milk have an important role in udder resistance to infection in the involution period. Both proteins express antimicrobial activity- lactoferrin by the binding and sequestration of iron ion; and immunoglobulin G by complement activation, bacterial opsonization and agglutination. Many factors affect lactoferrin and immunoglobulin G concentrations in bovine milk, such as the stage of lactation, milk production, and intramammary infections. The aim of this study was to determine concentrations of lactoferrin and immunoglobulin G in milk from healthy cows and subclinical mastitic cows during the late lactation period, and to evaluate the relationship between them.Materials, Methods & Results: A total of 150 quarter milk samples from 41 cows (Holstein-Friesian breed) in late lactation period were reviewed in this study. Milk samples were collected during morning milking, using aseptic techniques in sterile test tubes. From each sample, 0.1 mL of milk was plated on Columbia blood agar base with 5% defibrinated ovine blood, MacConkey agar and Sabouraud dextrose agar and incubated for 24 h - 48 h (bacteria) and 5 days (yeasts, mould) at 37oC. Milk samples for detection lactoferrin and immunoglobulin G concentration were skimmed at 1,400 g for 45 min and stored at -20°C until analysis. Lactoferrin concentration in bovine milk was determined using the Bovine Lactoferrin ELISA Quantitation Set. Milk samples were diluted at a ratio of 1:10,000. Plates were read at 450 nm absorbence values. Immunoglobulin G concentration was determined by the immunodiffusion method using radial immunodiffusion (RID) plates. Milk samples were diluted in a ratio of 1:30. Reading of results was done after incubation for 48 h by measuring the diameter of the precipitation ring. The highest mean lactoferrin concentration was observed in udder quarters infected with contagious pathogens (Streptococcus agalactiae and Staphylococcus aureus), while the highest mean immunoglobulin G concentration was detected in milk samples where minor mastitis pathogens (coagulase-negative staphylococci and Corynebacterium spp.) were isolated. Milk samples where Staphylococcus aureus was isolated had the lowest immunoglobulin G concentration, and the lowest lactoferrin concentration was observed in samples infected with enviromental pathogens (Streptococcus dysgalactiae).Discussion: This study showed that lactoferrin and immunoglobulin G concentrations are higher in milk samples from subclinical mastitic cows than in milk from normal lactating cows. Lactoferrin concentrations in milk samples from udder quarters infected with major mastitis pathogens were significantly higher than in milk infected with minor mastitis pathogens. The lowest concentration of immunoglobulin G was detected in milk samples where Staphylococcus aureus was isolated, while the highest immunoglobulin G concentration was observed in milk samples from quarters infected with minor mastitis pathogens. Lactoferrin and immunoglobulin G concentrations were significantly and positively correlated in all milk samples. This means that cows with high lactoferrin concentrations have high immunoglobulin G concentrations. In quarter milk samples infected with Staphylococcus aureus, lactoferrin and immunoglobulin G concentrations were negatively correlated. The cause of these findings could be the suppression of local immune response of mammary gland.
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Chua, Wei-Jen, Steven M. Truscott, Christopher S. Eickhoff, Azra Blazevic, Daniel F. Hoft, and Ted H. Hansen. "Polyclonal Mucosa-Associated Invariant T Cells Have Unique Innate Functions in Bacterial Infection." Infection and Immunity 80, no. 9 (July 9, 2012): 3256–67. http://dx.doi.org/10.1128/iai.00279-12.
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ABSTRACTMucosa-associated invariant T (MAIT) cells are a unique population of αβ T cells in mammals that reside preferentially in mucosal tissues and express an invariant Vα paired with limited Vβ T-cell receptor (TCR) chains. Furthermore, MAIT cell development is dependent upon the expression of the evolutionarily conserved major histocompatibility complex (MHC) class Ib molecule MR1. Usingin vitroassays, recent studies have shown that mouse and human MAIT cells are activated by antigen-presenting cells (APCs) infected with diverse microbes, including numerous bacterial strains and yeasts, but not viral pathogens. However, whether MAIT cells play an important, and perhaps unique, role in controlling microbial infection has remained unclear. To probe MAIT cell function, we show here that purified polyclonal MAIT cells potently inhibit intracellular bacterial growth ofMycobacterium bovisBCG in macrophages (MΦ) in coculture assays, and this inhibitory activity was dependent upon MAIT cell selection by MR1, secretion of gamma interferon (IFN-γ), and an innate interleukin 12 (IL-12) signal from infected MΦ. Surprisingly, however, the cognate recognition of MR1 by MAIT cells on the infected MΦ was found to play only a minor role in MAIT cell effector function. We also report that MAIT cell-deficient mice had higher bacterial loads at early times after infection compared to wild-type (WT) mice, demonstrating that MAIT cells play a unique role among innate lymphocytes in protective immunity against bacterial infection.
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Ariyarathne, H. M., Dermot P. Coyne, and Geunhwa Jung. "Construction of a Genetic Linkage Map and Locations of Halo Blight and Brown Spot Resistance Loci in Common Bean (Phaseolus vulgaris L.) using RAPD Markers." HortScience 32, no. 3 (June 1997): 451D—451. http://dx.doi.org/10.21273/hortsci.32.3.451d.
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Halo blight (HB), brown spot (BS), and rust incited by the bacterial pathogens Pseudomonas syringae pv. phaseolicola (Psp), Pseudomonas syringae pv. syringae (Pss) and the fungal pathogen Uromyces appendiculatus, respectively, are important diseases of common beans. The objectives were to construct a RAPD linkage map, and to locate HB and BS resistance genes and genes for some other traits. One-hundred-seventy RAPD markers were mapped in 78 RI lines of the cross BelNeb 1 and A 55. Eleven main and nine minor linkage groups were identified. MAPMAKER/QTL, interval mapping, was used to identify genomic regions involved in the genetic control of the traits. One region was found to control HB leaf reactions to strain HB16 while three regions controlled reactions to strain HB 83. These regions accounted for 22% and 18%, 17%, and 17% of phenotypic variation of resistance, respectively. Four putative QTLs were identified for resistance to BS, and accounted for 37%, 26%, 23%, and 19% of the phenotypic variation. Rust resistance was determined by a single major gene to both rust strains US85NP 5-1 and D82vc74fh. However, linked markers were not identified. The V gene controlling flower and stem color was tightly linked with the Operon marker O10.620.
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Byappanahalli, M., and R. Fujioka. "Indigenous soil bacteria and low moisture may limit but allow faecal bacteria to multiply and become a minor population in tropical soils." Water Science and Technology 50, no. 1 (July 1, 2004): 27–32. http://dx.doi.org/10.2166/wst.2004.0009.
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The soil environment in Hawaii is generally characterised as sub-optimal but permissive to support the in situ growth of E. coli and enterococci. However, soil desiccation and competition for nutrients by major indigenous soil microflora have been identified as potential factors that could limit a rapid and continual growth of faecal indicator bacteria in this soil environment. Despite these limitations, the genetic capacities of E. coli and enterococci are robust enough to enable these bacteria to become established as minor populations of Hawaii's soil microflora. Although the concentrations of E. coli and enterococci may have represented a fraction of the total soil microbiota, their presence in this habitat was very significant, for two important reasons: (a) soil was a major environmental source of E. coli and enterococci, and (b) the elevated counts of these bacteria in streams that routinely exceeded the EPA standards were due to run-off from soil. As a result, E. coli and enterococci were inadequate indicators to measure the degree of faecal contamination and potential presence of sewage-borne pathogens in Hawaiian streams.
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Bagdonas, Rokas, Algimantas Tamelis, Rytis Rimdeika, and Mindaugas Kiudelis. "Nudegusių ligonių ir jų žaizdų patogenų analizė." Lietuvos chirurgija 2, no. 3 (January 1, 2004): 0. http://dx.doi.org/10.15388/lietchirur.2004.3.2358.
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Rokas Bagdonas, Algimantas Tamelis, Rytis Rimdeika, Mindaugas Kiudelis Įvadas / tikslas Didžiausia nudegimų chirurgijos problema yra infekcija, nuo kurios miršta daugiau kaip 50% visų nudegusių pacientų. Nudegimų žaizda greitai infekuojasi, kadangi žaizdos aplinka yra ideali mikroorganizmams atsirasti ir daugintis. Studijoje, patvirtintoje Universiteto etikos komiteto, analizuojami nudegę pacientai ir iš nudegimo žaizdų išskirti patogenai. Pacientai ir metodai Mes analizavome 2246 nudegusius pacientus (amžiaus vidurkis – 27 metai), gydytus KMU Chirurgijos klinikose 1997–2002 metais. Nudegimo sunkumas buvo vertintas pagal Amerikos nudegimų asociacijos (ABA) schemą. 2462 nudegimo žaizdos pasėliai (2246 pacientų) buvo paimti steriliu tamponu ir pasėti 5% kraujo ir MacConkey terpėse. Rezultatai Iš nudegusių pacientų 1447 (74%) buvo vyrai ir 799 (26%) – moterys (p < 0,001). Pacientų amžius – nuo 2 iki 47 metų. 1261 (56%, p < 0,05) pacientai patyrė lengvą, 522 – vidutinį ir 463 – sunkų kūno nudegimą. 2130 pasėliai (86,5%), paimti iš 2462 nudegimo žaizdų, buvo teigiami. Iš 2130 teigiamų pasėlių Staphylococcus aureus išskirtas 1110 (52,1%) pasėliuose, iš jų MRSA – 498 (23,4%). Išvados Jauni vyrai dažniausiai patiria lengvus kūno nudegimus. Nudegimo žaizda dažniausiai infekuojasi S. aureus mikroorganizmais. MRSA yra pagrindinis ligoninės patogenas, infekuojantis nudegimo žaizdą. Prasminiai žodžiai: nudegimo sunkumas, nudegimo žaizdos patogenai, išskirti sukėlėjai Analysis of burn patients and the isolated pathogens Rokas Bagdonas, Algimantas Tamelis, Rytis Rimdeika, Mindaugas KiudelisKaunas Medical University, Clinic of Surgery,Eivenių str. 2, LT-50009, Kaunas, LithuaniaE-mail: rbagdonas@hotmail.com Background / objective The major challenge for a burn team is infection, which is known to cause over 50% of burn deaths. Burns become infected, because the environment at the site of the wound is ideal for the proliferation of infecting organisms. This study, approved by the regional Ethics Committee, analyzes the features of burned patients and the rates of pathogens isolated from burn wounds. Patients and methods We studied 2246 burn patients (mean age 27 years) admitted to the tertiary academic hospital in 1997–2002. The differentiation of the severity of burn injury was based on the scheme of the American Burn Association (ABA). 2462 surface swabs for microbiological analysis were taken from all 2246 patients. The wound area was swabbed with an alginate swab and cultured in 5% blood and MacConkey agar. Results There were 1447 (74%) men and 799 (26%) women (p < 0.001), age range 2–47 years. There were 1261 patients (56%, p < 0.05) with minor, 522 with moderate and 463 with major burn injuries. 2130 swabs (86.5%) out of 2462 burn wound surface swabs were positive. Out of 2130 isolates positive for pathogenic bacterial culture, there were 1110 (52.1%) isolates positive for Staphylococcus aureus infection. The rate of MRSA was 23.4% (498 isolates). Conclusions Young male patients mostly have a minor burn injury. Burn wounds are most commonly infected with S. aureus. MRSA is still the main hospital pathogen in burns. Keywords: severity of the burn injury, burn swabs, isolated pathogens
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Westcott, Marlena M., Curtis J. Henry, Jacqueline E. Amis, and Elizabeth M. Hiltbold. "Dendritic Cells Inhibit the Progression of Listeria monocytogenes Intracellular Infection by Retaining Bacteria in Major Histocompatibility Complex Class II-Rich Phagosomes and by Limiting Cytosolic Growth." Infection and Immunity 78, no. 7 (April 19, 2010): 2956–65. http://dx.doi.org/10.1128/iai.01027-09.
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ABSTRACT Dendritic cells (DC) provide a suboptimal niche for the growth of Listeria monocytogenes, a facultative intracellular bacterial pathogen of immunocompromised and pregnant hosts. This is due in part to a failure of large numbers of bacteria to escape to the cytosol, an essential step in the intracellular life cycle that is mediated by listeriolysin O (LLO). Here, we demonstrate that wild-type bacteria that failed to enter the cytosol of bone marrow-derived DC were retained in a LAMP2+ compartment. An isogenic L. monocytogenes strain that produces an LLO protein with reduced pore-forming activity had a severe escape and growth phenotype in DC. Few mutant bacteria entered the cytosol in the first 2 h and were instead found in LAMP2+, major histocompatibility complex class II+ (MHC-II+) H2-DM vesicles characteristic of MHC-II antigen loading compartments (MIIC). In contrast, the mutant had a minor phenotype in bone marrow-derived macrophages (BMM) despite the reduced LLO activity. In the first hour, DC phagosomes acidified to a pH that was, on average, half a point higher than that of BMM phagosomes. Unlike BMM, L. monocytogenes growth in DC was minimal after 5 h, and consequently, DC remained viable and matured late in infection. Taken together, the data are consistent with a model in which phagosomal maturation events associated with the acquisition of MHC-II molecules present a suboptimal environment for L. monocytogenes escape to the DC cytosol, possibly by limiting the activity of LLO. This, in combination with an undefined mechanism that controls bacterial growth late in infection, promotes DC survival during the critical maturation response.
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Faralla, Cristina, Gabrielle A. Rizzuto, David E. Lowe, Byoungkwan Kim, Cara Cooke, Lawrence R. Shiow, and Anna I. Bakardjiev. "InlP, a New Virulence Factor with Strong Placental Tropism." Infection and Immunity 84, no. 12 (October 10, 2016): 3584–96. http://dx.doi.org/10.1128/iai.00625-16.
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Intrauterine infection is a major detriment for maternal-child health and occurs despite local mechanisms that protect the maternal-fetal interface from a wide variety of pathogens. The bacterial pathogenListeria monocytogenescauses spontaneous abortion, stillbirth, and preterm labor in humans and serves as a model for placental pathogenesis. Given the unique immunological environment of the maternal-fetal interface, we hypothesized that virulence determinants with placental tropism are required for infection of this tissue. We performed a genomic screen in pregnant guinea pigs that led to the identification of 201 listerial genes important for infection of the placenta but not maternal liver. Among these genes waslmrg1778(lmo2470), here namedinlP, predicted to encode a secreted protein that belongs to the internalin family. InlP is conserved in virulentL. monocytogenesstrains but absent inListeriaspecies that are nonpathogenic for humans. The intracellular life cycle ofL. monocytogenesdeficient ininlP(ΔinlP) was not impaired. In guinea pigs and mice, InlP increased the placental bacterial burden by a factor of 3 log10while having only a minor role in other maternal organs. Furthermore, the ΔinlPstrain was attenuated in intracellular growth in primary human placental organ cultures and trophoblasts. InlP is a novel virulence factor for listeriosis with a strong tropism for the placenta. This virulence factor represents a tool for the development of new modalities to prevent and treat infection-related pregnancy complications.
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Kerksiek, Kristen M., Dirk H. Busch, Ingrid M. Pilip, S. Elise Allen, and Eric G. Pamer. "H2-M3–Restricted T Cells in Bacterial Infection." Journal of Experimental Medicine 190, no. 2 (July 19, 1999): 195–204. http://dx.doi.org/10.1084/jem.190.2.195.
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Major histocompatibility complex (MHC) class Ib molecules have been implicated in CD8+ T cell–mediated defenses against intracellular bacterial infection, but the relative importance of MHC class Ib–restricted T cells in antimicrobial immunity is unknown. In this report, we use MHC tetramers to characterize T cell responses restricted by H2-M3, an MHC class Ib molecule that selectively presents N-formyl peptides. We find that sizeable H2-M3–restricted T cell responses, occurring earlier than MHC class Ia–restricted T cell responses, are mounted after primary infection with the intracellular bacterium Listeria monocytogenes. These H2-M3–restricted T cells are cytolytic and produce interferon γ. However, after a second L. monocytogenes infection, H2-M3–restricted memory T cell responses are minor in comparison to the much larger MHC class Ia–restricted responses. This first direct characterization of an MHC class Ib–restricted T cell response indicates that CD8+ T cells responding to L. monocytogenes infection can be divided into two groups: H2-M3–restricted responses, which provide rapid and quantitatively substantial effector function during primary infections but contribute relatively little to memory responses, and MHC class Ia–restricted responses, which expand later during primary infection but form memory T cells that respond rapidly and dramatically in response to subsequent infections by the same pathogen.
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Metzler-Zebeli, Barbara U., Seema Hooda, Robert Pieper, Ruurd T. Zijlstra, Andrew G. van Kessel, Rainer Mosenthin, and Michael G. G�nzle. "Nonstarch Polysaccharides Modulate Bacterial Microbiota, Pathways for Butyrate Production, and Abundance of Pathogenic Escherichia coli in the Pig Gastrointestinal Tract." Applied and Environmental Microbiology 76, no. 11 (April 9, 2010): 3692–701. http://dx.doi.org/10.1128/aem.00257-10.
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ABSTRACT The impact of nonstarch polysaccharides (NSP) differing in their functional properties on intestinal bacterial community composition, prevalence of butyrate production pathway genes, and occurrence of Escherichia coli virulence factors was studied for eight ileum-cannulated growing pigs by use of terminal restriction fragment length polymorphism (TRFLP) and quantitative PCR. A cornstarch- and casein-based diet was supplemented with low-viscosity, low-fermentability cellulose (CEL), with high-viscosity, low-fermentability carboxymethylcellulose (CMC), with low-viscosity, high-fermentability oat β-glucan (LG), and with high-viscosity, high-fermentability oat β-glucan (HG). Only minor effects of NSP fractions on the ileal bacterial community were observed, but NSP clearly changed the digestion in the small intestine. Compared to what was observed for CMC, more fermentable substrate was transferred into the large intestine with CEL, LG, and HG, resulting in higher levels of postileal dry-matter disappearance. Linear discriminant analysis of NSP and TRFLP profiles and 16S rRNA gene copy numbers for major bacterial groups revealed that CMC resulted in a distinctive bacterial community in comparison to the other NSP, which was characterized by higher gene copy numbers for total bacteria, Bacteroides-Prevotella-Porphyromonas, Clostridium cluster XIVa, and Enterobacteriaceae and increased prevalences of E. coli virulence factors in feces. The numbers of butyryl-coenzyme A (CoA) CoA transferase gene copies were higher than those of butyrate kinase gene copies in feces, and these quantities were affected by NSP. The present results suggest that the NSP fractions clearly and distinctly affected the taxonomic composition and metabolic features of the fecal microbiota. However, the effects were more linked to the individual NSP and to their effect on nutrient flow into the large intestine than to their shared functional properties.
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Wu, Wei, Lingzhi Huang, Qianzhuo Mao, Jing Wei, Jiajia Li, Yu Zhao, Qian Zhang, Dongsheng Jia, and Taiyun Wei. "Interaction of viral pathogen with porin channels on the outer membrane of insect bacterial symbionts mediates their joint transovarial transmission." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1767 (January 14, 2019): 20180320. http://dx.doi.org/10.1098/rstb.2018.0320.
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Many hemipteran insects that can transmit plant viruses in a persistent and transovarial manner are generally associated with a common obligate bacterial symbiont Sulcia and its β-proteobacterial partner. Rice dwarf virus (RDV), a plant reovirus, can bind to the envelope of Sulcia through direct interaction of the viral minor outer capsid protein P2 with the bacterial outer membrane protein, allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Here, we show that RDV can hitchhike with both Sulcia and its β-proteobacterial partner Nasuia to ensure their simultaneous transovarial transmission. Interestingly, RDV can move through the outer envelope of Nasuia and reside in the periplasmic space, which is mediated by the specific interaction of the viral major outer capsid protein P8 and the porin channel on the bacterial outer envelope. Nasuia porin-specific antibody efficiently interferes with the binding between RDV and the Nasuia envelope, thus strongly preventing viral transmission to insect offspring. Thus, RDV has evolved different strategies to exploit the ancient oocyte entry paths used by two obligate bacterial symbionts in rice leafhoppers. Our results thus reveal that RDV has formed complex, cooperative interactions with both Sulcia and Nasuia during their joint transovarial transmission. This article is part of the theme issue ‘Biotic signalling sheds light on smart pest management’.
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Du, Heshan, Changlong Wen, Xiaofen Zhang, Xiulan Xu, Jingjing Yang, Bin Chen, and Sansheng Geng. "Identification of a Major QTL (qRRs-10.1) That Confers Resistance to Ralstonia solanacearum in Pepper (Capsicum annuum) Using SLAF-BSA and QTL Mapping." International Journal of Molecular Sciences 20, no. 23 (November 23, 2019): 5887. http://dx.doi.org/10.3390/ijms20235887.
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The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt (BW), a major disease of pepper (Capsicum annuum). The genetic basis of resistance to this disease in pepper is not well known. This study aimed to identify BW resistance markers in pepper. Analysis of the dynamics of bioluminescent R. solanacearum colonization in reciprocal grafts of a resistant (BVRC 1) line and a susceptible (BVRC 25) line revealed that the resistant rootstock effectively suppressed the spreading of bacteria into the scion. The two clear-cut phenotypic distributions of the disease severity index in 440 F2 plants derived from BVRC 25 × BVRC 1 indicated that a major genetic factor as well as a few minor factors that control BW resistance. By specific-locus amplified fragment sequencing combined with bulked segregant analysis, two adjacent resistance-associated regions on chromosome 10 were identified. Quantitative trait (QTL) mapping revealed that these two regions belong to a single QTL, qRRs-10.1. The marker ID10-194305124, which reached a maximum log-likelihood value at 9.79 and accounted for 19.01% of the phenotypic variation, was located the closest to the QTL peak. A cluster of five predicted R genes and three defense-related genes, which are located in close proximity to the significant markers ID10-194305124 or ID10-196208712, are important candidate genes that may confer BW resistance in pepper.
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Quigley, Bernard R., Matthew Hatkoff, David G. Thanassi, Mahamoudou Ouattara, Zehava Eichenbaum, and June R. Scott. "A Foreign Protein Incorporated on the Tip of T3 Pili in Lactococcus lactis Elicits Systemic and Mucosal Immunity." Infection and Immunity 78, no. 3 (December 22, 2009): 1294–303. http://dx.doi.org/10.1128/iai.01037-09.
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ABSTRACT The use of Lactococcus lactis to deliver a chosen antigen to the mucosal surface has been shown to elicit an immune response in mice and is a possible method of vaccination in humans. The recent discovery on Gram-positive bacteria of pili that are covalently attached to the bacterial surface and the elucidation of the residues linking the major and minor subunits of such pili suggests that the presentation of an antigen on the tip of pili external to the surface of L. lactis might constitute a successful vaccine strategy. As a proof of principle, we have fused a foreign protein (the Escherichia coli maltose-binding protein) to the C-terminal region of the native tip protein (Cpa) of the T3 pilus derived from Streptococcus pyogenes and expressed this fusion protein (MBP*) in L. lactis. We find that MBP* is incorporated into pili in this foreign host, as shown by Western blot analyses of cell wall proteins and by immunogold electron microscopy. Furthermore, since the MBP* on these pili retains its native biological activity, it appears to retain its native structure. Mucosal immunization of mice with this L. lactis strain expressing pilus-linked MBP* results in production of both a systemic and a mucosal response (IgG and IgA antibodies) against the MBP antigen. We suggest that this type of mucosal vaccine delivery system, which we term UPTOP (for unhindered presentation on tips of pili), may provide an inexpensive and stable alternative to current mechanisms of immunization for many serious human pathogens.
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Aničić, Neda, Uroš Gašić, Feng Lu, Ana Ćirić, Marija Ivanov, Bojan Jevtić, Milena Dimitrijević, et al. "Antimicrobial and Immunomodulating Activities of Two Endemic Nepeta Species and Their Major Iridoids Isolated from Natural Sources." Pharmaceuticals 14, no. 5 (April 28, 2021): 414. http://dx.doi.org/10.3390/ph14050414.
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Two Balkan Peninsula endemics, Nepeta rtanjensis and N. argolica subsp. argolica, both characterized by specialized metabolite profiles predominated by iridoids and phenolics, are differentiated according to the stereochemistry of major iridoid aglycone nepetalactone (NL). For the first time, the present study provides a comparative analysis of antimicrobial and immunomodulating activities of the two Nepeta species and their major iridoids isolated from natural sources—cis,trans-NL, trans,cis-NL, and 1,5,9-epideoxyloganic acid (1,5,9-eDLA), as well as of phenolic acid rosmarinic acid (RA). Methanol extracts and pure iridoids displayed excellent antimicrobial activity against eight strains of bacteria and seven strains of fungi. They were especially potent against food-borne pathogens such as L. monocytogenes, E. coli, S. aureus, Penicillium sp., and Aspergillus sp. Targeted iridoids were efficient agents in preventing biofilm formation of resistant P. aeruginosa strain, and they displayed additive antimicrobial interaction. Iridoids are, to a great extent, responsible for the prominent antimicrobial activities of the two Nepeta species, although are probably minor contributors to the moderate immunomodulatory effects. The analyzed iridoids and RA, individually or in mixtures, have the potential to be used in the pharmaceutical industry as potent antimicrobials, and in the food industry to increase the shelf life and safety of food products.
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Leduc, Isabelle, C. Dinitra White, Igor Nepluev, Robert E. Throm, Stanley M. Spinola, and Christopher Elkins. "Outer Membrane Protein DsrA Is the Major Fibronectin-Binding Determinant of Haemophilus ducreyi." Infection and Immunity 76, no. 4 (January 22, 2008): 1608–16. http://dx.doi.org/10.1128/iai.00994-07.
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ABSTRACT The ability to bind extracellular matrix proteins is a critical virulence determinant for skin pathogens. Haemophilus ducreyi, the etiological agent of the genital ulcer disease chancroid, binds extracellular matrix components, including fibronectin (FN). We investigated H. ducreyi FN binding and report several important findings about this interaction. First, FN binding by H. ducreyi was greatly increased in bacteria grown on heme and almost completely inhibited by hemoglobin. Second, wild-type strain 35000HP bound significantly more FN than did a dsrA mutant in two different FN binding assays. Third, the expression of dsrA in the dsrA mutant restored FN binding and conferred the ability to bind FN to a non-FN-binding Haemophilus influenzae strain. Fourth, an anti-DsrA monoclonal antibody partially blocked FN binding by H. ducreyi. The hemoglobin receptor, the collagen-binding protein, the H. ducreyi lectin, the fine-tangle pili, and the outer membrane protein OmpA2 were not involved in H. ducreyi FN binding, since single mutants bound FN as well as the parent strain did. However, the major outer membrane protein may have a minor role in FN binding by H. ducreyi, since a double dsrA momp mutant bound less FN than did the single dsrA mutant. Finally, despite major sequence differences, DsrA proteins from both class I and class II H. ducreyi strains mediated FN and vitronectin binding. We concluded that DsrA is the major factor involved in FN binding by both classes of H. ducreyi strains.
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Marschal, Matthias, Johanna Bachmaier, Ingo Autenrieth, Philipp Oberhettinger, Matthias Willmann, and Silke Peter. "Evaluation of the Accelerate Pheno System for Fast Identification and Antimicrobial Susceptibility Testing from Positive Blood Cultures in Bloodstream Infections Caused by Gram-Negative Pathogens." Journal of Clinical Microbiology 55, no. 7 (April 26, 2017): 2116–26. http://dx.doi.org/10.1128/jcm.00181-17.
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ABSTRACT Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli ( n = 7) and multidrug-resistant Pseudomonas aeruginosa ( n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h ( P < 0.0001) and for AST by 40.39 h ( P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.
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Pilla, Rachel, Valentina Daprà, Alfonso Zecconi, and Renata Piccinini. "Hygienic and health characteristics of donkey milk during a follow-up study." Journal of Dairy Research 77, no. 4 (May 19, 2010): 392–97. http://dx.doi.org/10.1017/s0022029910000221.
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For its characteristics, donkey milk has been proposed as an alternative to goat or artificial milk to feed allergic infants. Therefore, it is important to increase our knowledge on health and immunological characteristics of donkey milk. Ten donkeys, bred as companion animals, were enrolled in this study and sampled once a month, for eight months. Milk (10 ml) was collected from each half udder for somatic cell count (SCC), bacteriological analysis and total bacteria count (TBC). The major pathogens were tested for antimicrobial susceptibility, and Staphylococcus aureus isolates were further genotyped by nanoarray analysis. Whey lysozyme and NAGase (NAG) activities were also assessed. Overall, 101 half-udder milk samples were taken. They showed very low values of TBC (<250 cfu/ml) and SCC (<50 000 cells/ml) and a minor prevalence of pathogens: Staph. aureus was isolated only from 5 milk samples (3 animals), Streptococcus equi from 2 samples and Str. equisimilis from a single sample. All the isolates were sensitive to all antibiotic classes used in veterinary medicine. None of the Staph. aureus isolates were shown to harbour genes coding for any enterotoxin, toxic-shock syndrome toxin or antibiotic resistance. Lysozyme levels were always very high (4000–5000 U/ml), while NAG values were mostly low (<50 U/ml), out of the last part of lactation. The results of this study confirmed the low prevalence of intramammary infections in donkey and the absence of food-borne pathogens, suggesting that donkey milk could be a safe food, if the mammary gland is healthy and the animals are milked in proper hygienic conditions.
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Hamad, Mohamad A., Chad R. Austin, Amanda L. Stewart, Mike Higgins, Andrés Vázquez-Torres, and Martin I. Voskuil. "Adaptation and Antibiotic Tolerance of Anaerobic Burkholderia pseudomallei." Antimicrobial Agents and Chemotherapy 55, no. 7 (May 2, 2011): 3313–23. http://dx.doi.org/10.1128/aac.00953-10.
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ABSTRACTThe Gram-negative bacteriumBurkholderia pseudomalleiis the etiological agent of melioidosis and is remarkably resistant to most classes of antibacterials. Even after months of treatment with antibacterials that are relatively effectivein vitro, there is a high rate of treatment failure, indicating that this pathogen alters its patterns of antibacterial susceptibility in response to cues encountered in the host. The pathology of melioidosis indicates thatB. pseudomalleiencounters host microenvironments that limit aerobic respiration, including the lack of oxygen found in abscesses and in the presence of nitric oxide produced by macrophages. We investigated whetherB. pseudomalleicould survive in a nonreplicating, oxygen-deprived state and determined if this physiological state was tolerant of conventional antibacterials.B. pseudomalleisurvived initial anaerobiosis, especially under moderately acidic conditions similar to those found in abscesses. Microarray expression profiling indicated a major shift in the physiological state of hypoxicB. pseudomallei, including induction of a variety of typical anaerobic-environment-responsive genes and genes that appear specific to anaerobicB. pseudomallei. Interestingly, anaerobicB. pseudomalleiwas unaffected by antibacterials typically used in therapy. However, it was exquisitely sensitive to drugs used against anaerobic pathogens. After several weeks of anaerobic culture, a significant loss of viability was observed. However, a stable subpopulation that maintained complete viability for at least 1 year was established. Thus, during the course of human infection, if a minor subpopulation of bacteria inhabited an oxygen-restricted environment, it might be indifferent to traditional therapy but susceptible to antibiotics frequently used to treat anaerobic infections.
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Tejada-Arranz, Alejandro, Rute G. Matos, Yves Quentin, Maxime Bouilloux-Lafont, Eloïse Galtier, Valérie Briolat, Etienne Kornobis, et al. "RNase R is associated in a functional complex with the RhpA DEAD-box RNA helicase in Helicobacter pylori." Nucleic Acids Research 49, no. 9 (April 24, 2021): 5249–64. http://dx.doi.org/10.1093/nar/gkab283.
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Abstract Ribonucleases are central players in post-transcriptional regulation, a major level of gene expression regulation in all cells. Here, we characterized the 3′-5′ exoribonuclease RNase R from the bacterial pathogen Helicobacter pylori. The ‘prototypical’ Escherichia coli RNase R displays both exoribonuclease and helicase activities, but whether this latter RNA unwinding function is a general feature of bacterial RNase R had not been addressed. We observed that H. pylori HpRNase R protein does not carry the domains responsible for helicase activity and accordingly the purified protein is unable to degrade in vitro RNA molecules with secondary structures. The lack of RNase R helicase domains is widespread among the Campylobacterota, which include Helicobacter and Campylobacter genera, and this loss occurred gradually during their evolution. An in vivo interaction between HpRNase R and RhpA, the sole DEAD-box RNA helicase of H. pylori was discovered. Purified RhpA facilitates the degradation of double stranded RNA by HpRNase R, showing that this complex is functional. HpRNase R has a minor role in 5S rRNA maturation and few targets in H. pylori, all included in the RhpA regulon. We concluded that during evolution, HpRNase R has co-opted the RhpA helicase to compensate for its lack of helicase activity.
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Balázs, Viktória Lilla, Lilla Nagy-Radványi, Rita Filep, Erika Kerekes, Béla Kocsis, Marianna Kocsis, and Ágnes Farkas. "In Vitro Antibacterial and Antibiofilm Activity of Hungarian Honeys against Respiratory Tract Bacteria." Foods 10, no. 7 (July 14, 2021): 1632. http://dx.doi.org/10.3390/foods10071632.
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Honey is a rich source of carbohydrates, while minor compounds such as amino acids and polyphenols contribute to its health-promoting effects. Honey is one of the oldest traditional remedies applied for microbial infections, due to its antibacterial, anti-inflammatory, and antioxidant properties. The aim of this study was to investigate the antibacterial and antibiofilm effects of Hungarian black locust, linden, and sunflower honeys against the most common biofilm-forming respiratory tract pathogens Haemophilus spp., Pseudomonas aeruginosa, and Streptococcus pneumoniae. The unifloral character of all three honey types was confirmed by melissopalynological analysis. The antibacterial activity of each honey sample against each bacterium strain was proven with agar well diffusion assay and thin layer chromatography—direct bioautography. Kinetics and mechanisms of antibacterial action were clarified with time-kill assay and membrane degradation study. The anti-biofilm activity was evidenced using crystal violet assay. In each assay, linden honey was the most effective, followed by sunflower and black locust honey. In addition, each honey sample had greater potential to suppress respiratory tract bacteria, compared to major sugar components. In conclusion, honey in general and linden honey in particular, can have a role in the treatment of respiratory tract infections caused by biofilm-forming bacteria.
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Nelson, Christian D. S., Luisa J. Ströh, Gretchen V. Gee, Bethany A. O'Hara, Thilo Stehle, and Walter J. Atwood. "Modulation of a Pore in the Capsid of JC Polyomavirus Reduces Infectivity and Prevents Exposure of the Minor Capsid Proteins." Journal of Virology 89, no. 7 (January 21, 2015): 3910–21. http://dx.doi.org/10.1128/jvi.00089-15.
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ABSTRACTJC polyomavirus (JCPyV) infection of immunocompromised individuals results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). The viral capsid of JCPyV is composed primarily of the major capsid protein virus protein 1 (VP1), and pentameric arrangement of VP1 monomers results in the formation of a pore at the 5-fold axis of symmetry. While the presence of this pore is conserved among polyomaviruses, its functional role in infection or assembly is unknown. Here, we investigate the role of the 5-fold pore in assembly and infection of JCPyV by generating a panel of mutant viruses containing amino acid substitutions of the residues lining this pore. Multicycle growth assays demonstrated that the fitness of all mutants was reduced compared to that of the wild-type virus. Bacterial expression of VP1 pentamers containing substitutions to residues lining the 5-fold pore did not affect pentamer assembly or prevent association with the VP2 minor capsid protein. The X-ray crystal structures of selected pore mutants contained subtle changes to the 5-fold pore, and no other changes to VP1 were observed. Pore mutant pseudoviruses were not deficient in assembly, packaging of the minor capsid proteins, or binding to cells or in transport to the host cell endoplasmic reticulum. Instead, these mutant viruses were unable to expose VP2 upon arrival to the endoplasmic reticulum, a step that is critical for infection. This study demonstrated that the 5-fold pore is an important structural feature of JCPyV and that minor modifications to this structure have significant impacts on infectious entry.IMPORTANCEJCPyV is an important human pathogen that causes a severe neurological disease in immunocompromised individuals. While the high-resolution X-ray structure of the major capsid protein of JCPyV has been solved, the importance of a major structural feature of the capsid, the 5-fold pore, remains poorly understood. This pore is conserved across polyomaviruses and suggests either that these viruses have limited structural plasticity in this region or that this pore is important in infection or assembly. Using a structure-guided mutational approach, we showed that modulation of this pore severely inhibits JCPyV infection. These mutants do not appear deficient in assembly or early steps in infectious entry and are instead reduced in their ability to expose a minor capsid protein in the host cell endoplasmic reticulum. Our work demonstrates that the 5-fold pore is an important structural feature for JCPyV.
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SCHULZ, Benjamin L., Andrew J. SLOANE, Leanne J. ROBINSON, Lucille T. SEBASTIAN, Allan R. GLANVILLE, Yuanlin SONG, Alan S. VERKMAN, Jenny L. HARRY, Nicolle H. PACKER, and Niclas G. KARLSSON. "Mucin glycosylation changes in cystic fibrosis lung disease are not manifest in submucosal gland secretions." Biochemical Journal 387, no. 3 (April 26, 2005): 911–19. http://dx.doi.org/10.1042/bj20041641.
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SMG (submucosal gland) secretions are a major component of the airway surface liquid, are associated with innate immunity in the lung, and have been reported to be altered in lung disease. Changes in lung mucosal glycosylation have been reported in CF (cystic fibrosis), which may be responsible for differential bacterial binding to glycosylated components in the lung mucosa and hence increased pre-disposition to pulmonary infection. Glycoproteomic analysis was performed on SMG secretions collected from explanted bronchial tissue of subjects with severe lung disease, with and without CF, and controls without lung disease. Mucins MUC5B and MUC5AC were shown to be the dominant high-molecular-mass glycoprotein components, with a minor non-mucin glycoprotein component, gp-340, also present. Oligosaccharides containing blood-group determinants corresponding to subjects' blood type were abundant on MUC5B/MUC5AC, as were Lewis-type epitopes and their sialylated analogues, which are ligands for pathogens and leucocytes. No significant differences were found in the glycosylation of MUC5B/MUC5AC or gp-340 between CF and non-CF subjects with severe lung disease, implying that CF does not influence SMG secretion mucin glycosylation in end-stage lung disease. There were also no significant differences found in the glycosylation of these components in severe lung disease compared with non-diseased lungs. This suggests that previously reported changes in the glycosylation of respiratory glycoconjugates in CF, and other pulmonary conditions, are not due to the glycosylation of components in SMG secretions, but may involve other secretions, responses or extracellular factors.
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EVELINE, EVELINE, and AGUSTIN NOVITA. "Antibacterial Potential of Star Anise (Illicium verum Hook. f.) Against Food Pathogen Bacteria." Microbiology Indonesia 14, no. 1 (July 1, 2020): 3. http://dx.doi.org/10.5454/mi.14.1.3.
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Star anise (Illicium verum Hook. f.) is commonly used as spice and flavor enhancer in food. Previous research revealed the presence of active compound which could inhibit bacterial growth. Thus, in order to apply star anise as natural antibacterial agent in food product, a further research concerning antibacterial activity and stability of star anise was conducted. Crude extract of star anise was obtained using ethanol and acetone with maceration method for 3 days, then diluted to 10, 20, 30, 40, and 50% (w/v). Well diffusion was conducted against three food spoilage bacteria (Staphylococcus aureus, Escherichia coli, and Bacillus cereus). Extract from ethanol with 30% concentration was selected as the best extract in which inhibit more than 6 mm inhibition zone with MIC and MBC value: 1.59% and 6.36% (S. aureus), 1.04% and 4.18% (E. coli), and 0.59% and 2.39% (B. cereus). This selected extract was used to test the extract stability against 4 levels of heating temperature (60, 70, 80, and 90°C) for 2 levels of heating time (15 and 30 minutes), and 4 levels of pH (4, 5, 6, and 7). Based on our results, different heating treatment and pH caused extract instability. Star anise extract was more stable at 60°C for 15 minutes heating treatment and pH 4, which resulting the lowest inhibition zone reduction compared to control extract. Star anise extract was categorized as low toxic compound (LC50 = 212.09 ppm). Terpenoids (anethole, 2,6-dimethyl-6-(4-methyl-3-pentenyl)-2-norpinene, β-caryophyllene, β-bisabolene) was founded as major antibacterial compound in star anise extract; fatty acid (6-octadecenoic acid, hexadecanoic acid, stearic acid) and benzaldehyde (4-anisaldehyde, p-allylanisole) were also founded as minor compound.
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Avenoso, Daniele, Anne Bradshaw, Andrew Innes, Josu de la Fuente, Eduardo Olavarria, Jane F. Apperley, and Jiří Pavlů. "Microbial Contamination of Haematopoietic Stem Cell Products: A Single Centre Experience." Blood 128, no. 22 (December 2, 2016): 5741. http://dx.doi.org/10.1182/blood.v128.22.5741.5741.
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Abstract Bacterial contamination of haematopoietic stem cell products (HSCP) during collection and processing is a potential risk and has been described as cause of serious morbidity and mortality. The rate of contamination is reported in the range of 0 to 4.5% in peripheral blood progenitor cell (PBPC) apheresis to as high as 26% in bone marrow (BM) harvests. Systematic microbiological testing is an important component of the HSCP quality assessment and identification of the bacteria involved helps in the management of early infective complications. Here we report the rate of contaminated HSCP collected in a single transplant centre, our policy of the management of this complication and the relevant clinical outcomes. This is a retrospective study of prospectively collected results of microbiological analyses of 246 collections performed from January 2015 till December 2015. Stem cells were collected by BM harvesting under general anaesthesia (N=47) and by PBPC apheresis (N=199) using Optia separator system. BM harvest rather then PBPC was performed on donor request or with donor consent where BM was clinically preferable over PBPC transplant. (eg. red cell disorders). Samples of HSCP for bacterial cultures were taken pre processing, post processing, including post filtration and at defined intervals during complex procedures. Cryoprotectant is also tested to check that no contamination has occurred during manufacture of the freeze mix. Samples were cultured in BACTEC™ Lytic/10 Anaerobic/F culture vials (pre-reduced enriched Soybean-Casein Digest broth with CO2) and in anaerobic blood cultures; BACTEC Peds Plus™/F culture vials (enriched Soybean-Casein Digest broth with CO2) under aerobic conditions, both for 14 days. Organisms were specifically identified in all positive HSCP. Sixteen bacterial contaminations of HSCP were recorded (6.09% of total collections). The most frequent product contaminated was BM (N=15, 31.9%); only one PBPC apheresis product was positive (0.5%). The following bacteria were isolated: propionibacterium (N=7), coagulase negative staphylococcus (N=4), micrococcus (N=2), staphylococcus capitis (N=1), Staphylococcus epidermidis (N=2). Seven HSCP were not infused: one patient died before undergoing to transplant, two products have been collected as stem cell rescue in case of graft failure from allogeneic donors, four collections were stored for future use. Nine patients received contaminated HSCPs. After being contemporaneously alerted to the contamination, the clinical team performed daily blood cultures (BC). From these 9 patients only two minor clinical events were recorded; One, a non-neutropaenic fever on day +2 (S. Capitis cultured from HSCP, BC negative) and the other a positive BC (micrococcus cultured from both HSCP and BC) in a patient without fever or signs of infection. Both were treated with IV vancomycin on microbiology advice. These data showed a rate of bacterial contamination of HSCP comparable with reports from other groups. Moreover, at our centre no major clinical events were recorded after the infusion of contaminated HSCP. In this small study, the most frequent source of contaminated HSCP was BM and the most frequently isolated pathogens were skin commensals. No consensus exists on the requirement for antibiotics after the infusion of contaminated HSCP. Our experience supports a strategy of symptomatic management based on fevers or positive blood cultures with targeted antibiotics based on in vitro sensitivities rather than pre-emptive empirical treatment of all patients. Disclosures Apperley: Bristol Myers Squibb: Honoraria, Speakers Bureau; Ariad: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Incyte: Speakers Bureau; Novartis: Honoraria, Speakers Bureau.
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El Mortaji, Lamya, Sylvie Aubert, Eloïse Galtier, Christine Schmitt, Karine Anger, Yulia Redko, Yves Quentin, and Hilde De Reuse. "The Sole DEAD-Box RNA Helicase of the Gastric PathogenHelicobacter pyloriIs Essential for Colonization." mBio 9, no. 2 (March 27, 2018): e02071-17. http://dx.doi.org/10.1128/mbio.02071-17.
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ABSTRACTPresent in every kingdom of life, generally in multiple copies, DEAD-box RNA helicases are specialized enzymes that unwind RNA secondary structures. They play major roles in mRNA decay, ribosome biogenesis, and adaptation to cold temperatures. Most bacteria have multiple DEAD-box helicases that present both specialized and partially redundant functions. By using phylogenomics, we revealed that theHelicobactergenus, including the major gastric pathogenH. pylori, is among the exceptions, as it encodes a sole DEAD-box RNA helicase. InH. pylori, this helicase, designated RhpA, forms a minimal RNA degradosome together with the essential RNase, RNase J, a major player in the control of RNA decay. Here, we usedH. pylorias a model organism with a sole DEAD-box helicase and investigated the role of this helicase inH. pyloriphysiology, ribosome assembly, and duringin vivocolonization. Our data showed that RhpA is dispensable for growth at 37°C but crucial at 33°C, suggesting an essential role of the helicase in cold adaptation. Moreover, we found that a ΔrhpAmutant was impaired in motility and deficient in colonization of the mouse model. RhpA is involved in the maturation of 16S rRNA at 37°C and is associated with translating ribosomes. At 33°C, RhpA is, in addition, recruited to individual ribosomal subunits. Finally, via its role in the RNA degradosome, RhpA directs the regulation of the expression of its partner, RNase J. RhpA is thus a multifunctional enzyme that, inH. pylori, plays a central role in gene regulation and in the control of virulence.IMPORTANCEWe present the results of our study on the role of RhpA, the sole DEAD-box RNA helicase encoded by the major gastric pathogenHelicobacter pylori. We observed that all theHelicobacterspecies possess such a sole helicase, in contrast to most free-living bacteria. RhpA is not essential for growth ofH. pyloriunder normal conditions. However, deletion ofrhpAleads to a motility defect and to total inhibition of the ability ofH. pylorito colonize a mouse model. We also demonstrated that this helicase encompasses most of the functions of its specialized orthologs described so far. We found that RhpA is a key element of the bacterial adaptation to colder temperatures and plays a minor role in ribosome biogenesis. Finally, RhpA regulates transcription of thernjgene encoding RNase J, its essential partner in the minimalH. pyloriRNA degradosome, and thus plays a crucial role in the control of RNA decay.
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Brisse, Sylvain, Cees M. Verduin, Dana Milatovic, Ad Fluit, Jan Verhoef, Severine Laevens, Peter Vandamme, Burkhard Tümmler, Henri A. Verbrugh, and Alex van Belkum. "Distinguishing Species of the Burkholderia cepacia Complex and Burkholderia gladioli by Automated Ribotyping." Journal of Clinical Microbiology 38, no. 5 (2000): 1876–84. http://dx.doi.org/10.1128/jcm.38.5.1876-1884.2000.
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Several species belonging to the genus Burkholderia are clinically relevant, opportunistic pathogens that inhabit major environmental reservoirs. Consequently, the availability of means for adequate identification and epidemiological characterization of individual environmental or clinical isolates is mandatory. In the present communication we describe the use of the Riboprinter microbial characterization system (Qualicon, Warwick, United Kingdom) for automated ribotyping of 104 strains of Burkholderia species from diverse sources, including several publicly accessible collections. The main outcome of this analysis was that all strains were typeable and that strains of Burkholderia gladioli and of each species of the B. cepacia complex, includingB. multivorans, B. stabilis, and B. vietnamiensis, were effectively discriminated. Furthermore, different ribotypes were discerned within each species. Ribotyping results were in general agreement with strain classification based on restriction fragment analysis of 16S ribosomal amplicons, but the resolution of ribotyping was much higher. This enabled automated molecular typing below the species level. Cluster analysis of the patterns obtained by ribotyping (riboprints) showed that withinB. gladioli, B. multivorans, and B. cepacia genomovar VI, the different riboprints identified always clustered together. Riboprints of B. cepacia genomovars I and III, B. stabilis, and B. vietnamiensis did not show distinct clustering but rather exhibited the formation of loose assemblages within which several smaller, genomovar-specific clusters were delineated. Therefore, ribotyping proved useful for genomovar identification. Analysis of serial isolates from individual patients demonstrated that infection with a single ribotype had occurred, despite minor genetic differences that were detected by pulsed-field gel electrophoresis of DNA macrorestriction fragments. The automated approach allows very rapid and reliable identification and epidemiological characterization of strains and generates an easily manageable database suited for expansion with information on additional bacterial isolates.
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Ozer, Egon A., Ekpeno Nnah, Xavier Didelot, Rachel J. Whitaker, and Alan R. Hauser. "The Population Structure of Pseudomonas aeruginosa Is Characterized by Genetic Isolation of exoU+ and exoS+ Lineages." Genome Biology and Evolution 11, no. 7 (June 7, 2019): 1780–96. http://dx.doi.org/10.1093/gbe/evz119.
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AbstractThe diversification of microbial populations may be driven by many factors including adaptation to distinct ecological niches and barriers to recombination. We examined the population structure of the bacterial pathogen Pseudomonas aeruginosa by analyzing whole-genome sequences of 739 isolates from diverse sources. We confirmed that the population structure of P. aeruginosa consists of two major groups (referred to as Groups A and B) and at least two minor groups (Groups C1 and C2). Evidence for frequent intragroup but limited intergroup recombination in the core genome was observed, consistent with sexual isolation of the groups. Likewise, accessory genome analysis demonstrated more gene flow within Groups A and B than between these groups, and a few accessory genomic elements were nearly specific to one or the other group. In particular, the exoS gene was highly overrepresented in Group A compared with Group B isolates (99.4% vs. 1.1%) and the exoU gene was highly overrepresented in Group B compared with Group A isolates (95.2% vs. 1.8%). The exoS and exoU genes encode effector proteins secreted by the P. aeruginosa type III secretion system. Together these results suggest that the major P. aeruginosa groups defined in part by the exoS and exoU genes are divergent from each other, and that these groups are genetically isolated and may be ecologically distinct. Although both groups were globally distributed and caused human infections, certain groups predominated in some clinical contexts.
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Gaspar, Andrew H., and Hung Ton-That. "Assembly of Distinct Pilus Structures on the Surface of Corynebacterium diphtheriae." Journal of Bacteriology 188, no. 4 (February 15, 2006): 1526–33. http://dx.doi.org/10.1128/jb.188.4.1526-1533.2006.
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ABSTRACT Different surface organelles contribute to specific interactions of a pathogen with host tissues or infectious partners. Multiple pilus gene clusters potentially encoding different surface structures have been identified in several gram-positive bacterial genomes sequenced to date, including actinomycetales, clostridia, corynebacteria, and streptococci. Corynebacterium diphtheriae has been shown to assemble a pilus structure, with sortase SrtA essential for the assembly of a major subunit SpaA and two minor proteins, SpaB and SpaC. We report here the characterization of a second pilus consisting of SpaD, SpaE, and SpaF, of which SpaD and SpaE form the pilus shaft and SpaF may be located at the pilus tip. The structure of the SpaDEF pilus contains no SpaABC pilins as detected by immunoelectron microscopy. Neither deletion of spaA nor sortase srtA abolishes SpaDEF pilus formation. The assembly of the SpaDEF pilus requires specific sortases located within the SpaDEF pilus gene cluster. Although either sortase SrtB or SrtC is sufficient to polymerize SpaDF, the incorporation of SpaE into the SpaD pili requires sortase SrtB. In addition, an alanine in place of the lysine of the SpaD pilin motif abrogates pilus polymerization. Thus, SpaD, SpaE, and SpaF constitute a different pilus structure that is independently assembled and morphologically distinct from the SpaABC pili and possibly other pili of C. diphtheriae.
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Marlina. "MULTIDRUG RESISTANCE (MDR) OF V. Parahaemolyticus." Jurnal Riset Kimia 2, no. 2 (February 12, 2015): 112. http://dx.doi.org/10.25077/jrk.v2i2.150.
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Vol. 2, No. 2 ABSTRACT A total of 97 V. parahaemolyticus isolate from Padang were examined for their resistance to 15 antibiotics. V. parahaemolyticus isolated behaved as resistant to sulfamethoxazole (100%), rifampin (95%) and tetracycline (75%) and sensitive to norfloxacin (96%). Ampicillin still sensitive for V. parahaemolyticus isolated from human stools. All of isolates were sensitive to namely chloramphenicol and floroquinolones (ciprofloxacin and norfloxacin agents). RAPD-PCR profiling with three primers (OPAR3, OPAR4 and OPAR8) produced four major clusters (R1, R2, R3 and R4), 7 minor clusters (I, II, III, IV, V, VI and VII) and three single isolates. Keywords: V. parahaemolyticus, MDR, RAPD 1. D. Ottaviani, I. Bacchiocchi, L. Masini, F. Leoni, A. Carraturo, M. Giammarioli, and G. Sbaraglia, Antimicrobial susceptibility of potentially halophilic vibrios isolated from seafood, International Journal of Antimicrobial Agents 18: 135-140, (2001).2. A. Cespedes, and E. Larson, Knowledge, attitude and practices regarding antibiotic use among Latinos in the United States: Review and Recommendations, American Journal of Infection Control 34: 495-502, (2006).3. M. Lesmana, D. Subekti, C.H. Simanjuntak, P. Tjaniadi, J. R. Campbell, and B. A. Ofoyo, Vibrio parahaemolyticus associated with cholera-like diarrhea among patients in North Jakarta, Indonesia, Diagnostic Microbiology and Infectious Disease, 39: 71-75, (2001).4. S. Lu, B. Liu, B. Zhou, And R. E. Levin, Incidence and Enumeration of Vibrio parahaemolyticus in Shellfish from two retail Sources and the Genetic Diversity of isolates as Determined by RAPD-PCR Analysis, Food Biotechnology, 20: 193-209, (2006).5. M. Nishibuchi, Vibrio parahaemolyticus. In International handbook of foodborne pathogens, ed. M.D. Milliots and J. W. Bier, United States: Marcel Dekker, Inc. P, 2004, 237-252.6. L. Poirel, M. R. Martinez, H. Mammeri, A. Liard, and P. Nordmann, Origin of Plasmid-Mediated Quinolone Resistance Determinant QnrA, Antimicrobial Agents and Chemotherapy, 49: 3523-3525, (2005).7. S. Radu, N. Elhadi, Z. Hassan, G. Rusul, S. Lihan, N. Fifadara, Yuherman and E. Purwati, Characterization of Vibrio vulnificus isolated from cockles (Anadara granosa): antimicrobial resistance, plasmid profiles and random amplification of polymorphic DNA analysis, FEMS Microbiology Letters, 165: 139–143, (1998).8. S. Radu, N. Ahmad, F. H. Ling, and A. Reezal, Prevalence and resistance to antibiotics for Aeromonas species from retail fish in Malaysia, International of Journal Food Microbiology, 81: 261–266, (2003).9. B. Sarkar, N. R. Chowdhury, G. B. Nair, M. Nishibuchi, S. Yamasaki, Y. Takeda, S. K. Gupta, S. K. Bhattacharya, and Ramamurthy, Molecular characterization of Vibrio parahaemolyticus of similar serovars isolated from sewage and clinical cases of diarrhea in Calcutta, India, World Journal of Microbiology and Biotechnology, 19: 771-776, (2003). 10. S. Schwarz, and E. Chaslus-Dancla, Use of antimicrobials in veterinary medicine and mechanisms of resistance, Veterinary Residue, 32: 201–225, (2001).11. H. Sörum, and T.M. L’Abèe-Lund,. Antibiotic resistance in food-related bacteria – a result of interfering with the global web of bacterial genetics, International Journal of Food Microbiology, 78: 43–56, (2002).12. P. Tjaniadi, M. Lesmana, D. Subekti, N. Machpud, S. Komalarini, W. Santoso, C. H. Simanjuntak, N. Punjabi, J. R. Campbell, W. K. Alexander, H. J. Beecham, A. L. Corwin, and B. A. Oyofo, Antimicrobial Resistance of Bacterial Pathogens Associated with Diarrheal Patients in Indonesia, American Journal of Tropical Medicine and Hygiene, 68: 666-670, (2003).13. X. Zhao, and D. Drlica, Restricting the Selection of Antibiotic-Resistant Mutants: A General Strategy Derived from Fluoroquinolone Studies, Clinical Infectious Diseases, 33: S147-S156, (2001).
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JUNEJA, VIJAY K., M. L. BARI, Y. INATSU, S. KAWAMOTO, and MENDEL FRIEDMAN. "Thermal Destruction of Escherichia coli O157:H7 in Sous-Vide Cooked Ground Beef as Affected by Tea Leaf and Apple Skin Powders†." Journal of Food Protection 72, no. 4 (April 1, 2009): 860–65. http://dx.doi.org/10.4315/0362-028x-72.4.860.
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We investigated the heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of white and green tea powders and an apple skin extract. Inoculated meat was cooked using the sous-vide technique, i.e., the meat was packaged in sterile bags and completely immersed in a circulating water bath at low temperature for a period of time. The bags were cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held from 240 min at 55°C to 10 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol-MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time, in minutes, required for the bacteria to decrease by 90%) in the control beef ranged from 67.79 min at 55°C to 2.01 min at 62.5°C. D-values determined by a logistic model ranged from 36.22 (D1, the D-value of a major population of surviving cells) and 112.79 (D2, the D-value of a minor subpopulation) at 55°C to 1.39 (D1) and 3.00 (D2) at 62.5°C. A significant increase (P < 0.05) in the sensitivity of the bacteria to heat was observed with the addition of 3% added antimicrobials. D-value reductions of 62 to 74% were observed with apple powder and 18 to 58% with tea powders. Thermal death times from this study will assist the retail food industry to design cooking regimes that ensure the safety of beef contaminated with E. coli O157:H7.
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Lundström, Susanna L., Jianjun Li, Martin Månsson, Marisol Figueira, Magali Leroy, Richard Goldstein, Derek W. Hood, E. Richard Moxon, James C. Richards, and Elke K. H. Schweda. "Application of Capillary Electrophoresis Mass Spectrometry and Liquid Chromatography Multiple-Step Tandem Electrospray Mass Spectrometry To Profile Glycoform Expression during Haemophilus influenzae Pathogenesis in the Chinchilla Model of Experimental Otitis Media." Infection and Immunity 76, no. 7 (May 5, 2008): 3255–67. http://dx.doi.org/10.1128/iai.01710-07.
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ABSTRACT Otitis media caused by nontypeable Haemophilus influenzae (NTHi) is a common and recurrent bacterial infection of childhood. The structural variability and diversity of H. influenzae lipopolysaccharide (LPS) glycoforms are known to play a significant role in the commensal and disease-causing behavior of this pathogen. In this study, we determined LPS glycoform populations from NTHi strain 1003 during the course of experimental otitis media in the chinchilla model of infection by mass spectrometric techniques. Building on an established structural model of the major LPS glycoforms expressed by this NTHi strain in vitro (M. Månsson, W. Hood, J. Li, J. C. Richards, E. R. Moxon, and E. K. Schweda, Eur. J. Biochem. 269:808-818, 2002), minor isomeric glycoform populations were determined by liquid chromatography multiple-step tandem electrospray mass spectrometry (LC-ESI-MS n ). Using capillary electrophoresis ESI-MS (CE-ESI-MS), we determined glycoform profiles for bacteria from direct middle ear fluid (MEF) samples. The LPS glycan profiles were essentially the same when the MEF samples of 7 of 10 animals were passaged on solid medium (chocolate agar). LC-ESI-MS n provided a sensitive method for determining the isomeric distribution of LPS glycoforms in MEF and passaged specimens. To investigate changes in LPS glycoform distribution during the course of infection, MEF samples were analyzed at 2, 5, and 9 days postinfection by CE-ESI-MS following minimal passage on chocolate agar. As previously observed, sialic acid-containing glycoforms were detected during the early stages of infection, but a trend toward more-truncated and less-complex LPS glycoforms that lacked sialic acid was found as disease progressed.
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Mélançon, D., and D. Grenier. "Production and Properties of Bacteriocin-Like Inhibitory Substances from the Swine Pathogen Streptococcus suis Serotype 2." Applied and Environmental Microbiology 69, no. 8 (August 2003): 4482–88. http://dx.doi.org/10.1128/aem.69.8.4482-4488.2003.
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ABSTRACT Streptococcus suis serotype 2 is a major pathogen found in the upper respiratory tract of swine. In this study, isolates of this bacterial species were tested for the production of bacteriocin-like inhibitory substances (BLIS). Of the 38 strains tested, four inhibited the growth of other S. suis isolates according to a deferred-antagonism plate assay. Interestingly, three of the strains were originally isolated from healthy carrier pigs and were considered nonvirulent. Three isolates (94-623, 90-1330, and AAH4) that produced BLIS in liquid broth were selected for further characterization. None of the inhibitory activities was related to the production of either organic acids or hydrogen peroxide. The BLIS produced by these strains were heat stable and proteinase K, pronase, and elastase sensitive but were trypsin and chymotrypsin resistant. They were stable at pH 2 and 12 and had molecular masses in the range of 14 to 30 kDa. Maximum production was observed during the mid-log phase. Following a curing procedure with novobiocin, only 90-1330 lost the ability to produce BLIS, suggesting that the BLIS might be plasmid encoded. Analysis of the inhibitory spectra revealed that the BLIS-producing strains also inhibited the growth of Actinobacillus minor, Actinobacillus porcinus, Enterococcus durans, Micrococcus luteus, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. dysgalactiae, Streptococcus equi subsp. zooepidemicus, and S. dysgalactiae subsp. equisimilis. This study reports for the first time the ability of the swine pathogen S. suis serotype 2 to produce BLIS with the characteristics of classic bacteriocins. Further studies are required to investigate the possibility of using bacteriocin-producing strains to prevent swine infections caused by virulent strains of S. suis serotype 2.
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JUNEJA, VIJAY K., and MENDEL FRIEDMAN. "Carvacrol and Cinnamaldehyde Facilitate Thermal Destruction of Escherichia coli O157:H7 in Raw Ground Beef†." Journal of Food Protection 71, no. 8 (August 1, 2008): 1604–11. http://dx.doi.org/10.4315/0362-028x-71.8.1604.
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The heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of the antimicrobials carvacrol and cinnamaldehyde was tested at temperatures ranging from 55 to 62.5°C. Inoculated meat packaged in bags was completely immersed in a circulating water bath, cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held for predetermined lengths of time ranging from 210 min at 55°C to 5 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time for the bacteria to decrease by 90%) in the control beef ranged from 63.90 min at 55°C to 1.79 min at 62.5°C. D-values determined by a logistic model ranged from 43.18 min (D1, the D-value of a major population of surviving cells) and 89.84 min (D2, the D-value of a minor subpopulation) at 55°C to 1.77 (D1) and 0.78 min (D2) at 62.5°C. The thermal death times suggested that to achieve a 4-D reduction, contaminated processed ground beef should be heated to an internal temperature of 60°C for at least 30.32 min. Significantly increased sensitivity to heat (P < 0.05) was observed with the addition and/or increasing levels of carvacrol or cinnamaldehyde from 0.5 to 1.0%. The observed thermal death times may facilitate the design of acceptance limits at critical control points for ground beef at lower times and temperatures of heating.
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Riley, Donald E., Richard E. Berger, David C. Miner, and John N. Krieger. "Diverse and Related 16S rRNA-Encoding DNA Sequences in Prostate Tissues of Men with Chronic Prostatitis." Journal of Clinical Microbiology 36, no. 6 (1998): 1646–52. http://dx.doi.org/10.1128/jcm.36.6.1646-1652.1998.
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Treatment of chronic prostatitis/chronic pelvic pain syndrome is often empirical because clinical culture methods fail to detect prostate-associated pathogens in >90% of patients. Previously, we tested a variety of specific-microorganism PCRs and began a DNA sequence study after we found that 77% of prostatitis patients were PCR positive for prokaryotic rRNA-encoding DNA sequences (rDNAs) despite negative cultures using optimal techniques. In the present study, 36 rDNA clones from 23 rDNA-positive patients were sequenced. This study represents more than twice the total rDNA sequence and more than twice the number of patients in the previous study. The increased number of patients and clones sequenced allowed enhanced phylogenetic analyses and refinements in our view of rDNA species inhabiting the prostate. A continuum of related rDNAs that might be arbitrarily described as two major groups of rDNAs and several minor groups was found. Sequences termed Pros A, identified in 8 (35%) of 23 rDNA-positive patients, grouped withAeromonas spp. in phylogenetic studies. Sequences termed Pros B, identified in 17 (74%) of 23 rDNA-positive patients, were distinct from previously reported sequences, although all were >90% similar to known gram-negative bacteria. Of the nine patients for whom multiple rDNAs were sequenced, six had biopsy specimens containing rDNAs from more than one species. Four (17%) patients had rDNAs different from those of the Pros A and Pros B groups. Of these four, one patient had rDNA similar to that ofFlavobacterium spp., another had rDNA similar to that of Pseudomonas testosteroni, and two patients had rDNAs <70% similar to known rDNAs. These findings suggest that the prostate can harbor bacteria undetectable by traditional approaches. Most of these diverse sequences are not reported in environments outside the prostate. The sequence similarities suggest adaptation of limited groups of bacteria to the microenvironment of the prostate. Further studies may elucidate the relationship of prostate-associated bacteria to chronic prostatitis/chronic pelvic pain syndrome.
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Ambur, Ole Herman, Tonje Davidsen, Stephan A. Frye, Seetha V. Balasingham, Karin Lagesen, Torbjørn Rognes, and Tone Tønjum. "Genome dynamics in major bacterial pathogens." FEMS Microbiology Reviews 33, no. 3 (May 2009): 453–70. http://dx.doi.org/10.1111/j.1574-6976.2009.00173.x.
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Sidhu, Raminderdeep K., Nicholas D. Cavallaro, Cicero C. Pola, Michelle D. Danyluk, Eric S. McLamore, and Carmen L. Gomes. "Planar Interdigitated Aptasensor for Flow-Through Detection of Listeria spp. in Hydroponic Lettuce Growth Media." Sensors 20, no. 20 (October 12, 2020): 5773. http://dx.doi.org/10.3390/s20205773.
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Irrigation water is a primary source of fresh produce contamination by bacteria during the preharvest, particularly in hydroponic systems where the control of pests and pathogens is a major challenge. In this work, we demonstrate the development of a Listeria biosensor using platinum interdigitated microelectrodes (Pt-IME). The sensor is incorporated into a particle/sediment trap for the real-time analysis of irrigation water in a hydroponic lettuce system. We demonstrate the application of this system using a smartphone-based potentiostat for rapid on-site analysis of water quality. A detailed characterization of the electrochemical behavior was conducted in the presence/absence of DNA and Listeria spp., which was followed by calibration in various solutions with and without flow. In flow conditions (100 mL samples), the aptasensor had a sensitivity of 3.37 ± 0.21 kΩ log-CFU−1 mL, and the LOD was 48 ± 12 CFU mL−1 with a linear range of 102 to 104 CFU mL−1. In stagnant solution with no flow, the aptasensor performance was significantly improved in buffer, vegetable broth, and hydroponic media. Sensor hysteresis ranged from 2 to 16% after rinsing in a strong basic solution (direct reuse) and was insignificant after removing the aptamer via washing in Piranha solution (reuse after adsorption with fresh aptamer). This is the first demonstration of an aptasensor used to monitor microbial water quality for hydroponic lettuce in real time using a smartphone-based acquisition system for volumes that conform with the regulatory standards. The aptasensor demonstrated a recovery of 90% and may be reused a limited number of times with minor washing steps.
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Molina, Lívio R., Hudson N. Costa, Juliana M. Leão, Victor M. R. Malacco, Elias J. Facury Filho, Antônio U. Carvalho, and Camila F. A. Lage. "Efficacy of an internal teat seal associated with a dry cow intramammary antibiotic for prevention of intramammary infections in dairy cows during the dry and early lactation periods." Pesquisa Veterinária Brasileira 37, no. 5 (May 2017): 465–70. http://dx.doi.org/10.1590/s0100-736x2017000500007.
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ABSTRACT: The present study aimed to evaluate the use of an internal dry period teat seal containing bismuth subnitrate (Teatseal®, Zoetis®, Florham Park, Nova Jersey, USA) associated with a long-acting cloxacilin preparation (Orbenin® Extra dry cow, Zoetis®, Florham Park, Nova Jersey, USA), in preventing new infections during the dry-off and early postpartum period. A total of 150 Holstein cows (average production of 9,000 kg of milk per lactation), with four functional udder quarters without clinical mastitis was included in the study. All animals were dried-off 60 days before the expected calving date. Two teats positioned diagonal-contralaterally received only dry cow antibiotic, control group C (n=300) and the other two teats, treatment group T (n=300) received dry cow antibiotic and infusion with an internal teat seal. Data from SCC variable were transformed by log base-10 transformation. Duncan’s test was used accepting 5% as the level of statistical significance. The occurrence of intramammary infection (IMI) and chronicity rate, and frequency of microorganisms isolated at drying and immediately postpartum in teats of group C and group T were evaluated using a non-parametric Chi-square Test, accepting 10% as the statistical significance level. There was a decrease in the occurrence of new infections in the early postpartum in cows which the sealant was used (C=19.6%, T=11.4%). In the postpartum period, Gram-negative bacteria were isolated from 16 teats in C and seven in T. The greatest reduction was observed for Escherichia coli (8 vs 1) in group T. There was no effect using the internal sealant on the frequency of isolation of environmental Streptococus. The use of sealant reduced the prevalence of subclinical mastitis cows between drying-off and the early postpartum period (C=51% versus T=42%) and resulted in a lower somatic cell count (SCC) in the treatment group when compared with the control group (T=1,073x103, C=1,793x103). The use of the internal teat seal combined with dry cow antibiotic is effective in the prevention of IMI during the dry period and early lactation and results in the reduction of SCC in immediate postpartum period. The treatment is effective in reducing infection between dry-off and the immediate postpartum caused by major and minor pathogens. However, no effect on infections caused by contagious pathogens was observed.
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Abebe, Engidaw, Getachew Gugsa, and Meselu Ahmed. "Review on Major Food-Borne Zoonotic Bacterial Pathogens." Journal of Tropical Medicine 2020 (June 29, 2020): 1–19. http://dx.doi.org/10.1155/2020/4674235.
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Food-borne microorganisms are major pathogens affecting food safety and cause human illness worldwide as a result of consumption of foodstuff, mainly animal products contaminated with vegetative pathogens or their toxins. Most of these microbes have zoonotic importance resulting in significant impact on both public health and economic sectors. Bacteria are the causative agents of two-thirds of human food-borne diseases worldwide with high burden in developing countries. Hence, the objectives of this review paper are to highlight the background of food-borne bacterial pathogens and to review common major food-borne zoonotic bacterial pathogens. Food animals are the major reservoirs of many food-borne zoonotic bacterial pathogens, and food products of animal origin are the main vehicles of transmission. Meat, dairy products, and eggs are the main ways by which people are exposed to zoonotic bacteria. S. aureus, Salmonella species, Campylobacter species, L. monocytogenes, and E. coli are the major zoonotic bacterial pathogens which are the causative agents of food-borne illness and death in the world associated with consumption of contaminated animal products. Production of toxins and structural virulent factors are responsible for the pathogenesis of these bacteria. These major zoonotic bacteria cause human infections which are characterized mainly by gastrointestinal symptoms including nausea, vomiting, diarrhea, abdominal cramps, and other agent-specific symptoms. Some bacteria may cause severe complications. Conventional (culturing), serological, and molecular techniques are important for detection of these common zoonotic bacteria and their toxins in food. Good hygiene, GMP, sanitation in operating procedures, and implementation of standardized HACCP and pasteurization procedures are effective methods for the control and prevention. Currently, the emergence of multidrug-resistant zoonotic bacteria associated with consumption of contaminated animal products is a great concern for the public health, and there should be coordinated surveillance and monitoring system for food-borne zoonotic bacterial pathogens particularly in developing countries including Ethiopia.
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Ferrieri, Patricia. "Neonatal Susceptibility and Immunity to Major Bacterial Pathogens." Clinical Infectious Diseases 12, Supplement_4 (May 1, 1990): S394—S400. http://dx.doi.org/10.1093/clinids/12.supplement_4.s394.
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Amani, Soroush, Ali Mohammadi-Najafabadi, and Ali Ahmadi. "Comparison of Efficacy and Side Effects of Azithromycin and Co-Amoxiclav in the Treatment of Acute Sinusitis in Adults: A Randomized Clinical Trial." Global Journal of Health Science 8, no. 11 (March 23, 2016): 178. http://dx.doi.org/10.5539/gjhs.v8n11p178.
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<p><strong>BACKGROUND:</strong> Regarding high prevalence of common cold and sinusitis in Chaharmahal and Bakhtiari Province and the lack of studies on patients referring hospitals in this province, this study was conducted to determine and compare the efficacy and side effects of azithromycin and co-amoxiclav.<strong></strong></p><p><strong>METHODS:</strong> This study was a double-blinded randomized clinical trial. The study population of this clinical trial was consisted of 90 patients with acute sinusitis aged 12-65 years. At least two major criteria or one major criterion and two minor criteria with duration of at least 7 days and at most 28 days, were some of the sinusitis diagnostic criteria for inclusion of the patients into the study. The patients were examined for symptoms prior to and twice after the treatment. The treatment was administration with <strong>500 mg</strong> azithromycin tablet per day for three days in group 1 (G1) and <strong>625 mg</strong> co-amoxiclav tablet every <strong>8 h</strong> for 10 days in group 2 (G2). The data were analyzed by repeated measures analysis of variance, independent t-test, and chi-square in Stata software and P < 0.05 was considered significant.<strong></strong></p><p><strong>RESULTS: </strong>Mean±Standard deviation age of all patients was 32.14±9.91 years. Out of 90 participants in the study, 50 (55.56%) were male and the rest were female. The patients’ symptoms were quantitatively similar in the two groups (22.3±2 and 22.2±1.9 in G1 and G2, respectively) prior to the intervention. The score at second examination decreased to 3.7±2.1 in G1 and to 9.4±2.7 in G2, significantly different from that prior to intervention and between the two groups (P<0.001). Although the score decreased in the two groups at third examination, it was not significant in the two groups (P=0.652). The cure rate in azithromycin group was derived 87.5% and 88%, and in co-amoxiclav group 32.4% and 83.3% at the days 5 and 10 of treatment, respectively. The most prevalent side effects in the two groups were diarrhea and nausea. The prevalence of diarrhea was obtained 21% and 33% in G1 and G2, respectively. </p><strong>CONCLUSION: </strong>No significant difference in side effects was seen between the two groups. Although the cure was faster in the patients treated with azithromycin than those treated with co-amoxiclav, co-amoxiclav is still considered as adequately working against acute sinusitis bacterial pathogens. In view of this efficacy, co-amoxiclav seems to lead to no drug resistance and could be used to treat the patient
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Kalogridou-Vassiliadou, Despina, Konstantinos Manolkidis, and Afrodite Tsigoida. "Somatic cell counts in relation to infection status of the goat udder." Journal of Dairy Research 59, no. 1 (February 1992): 21–28. http://dx.doi.org/10.1017/s002202990003020x.
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SummaryBacteriological analyses, cell counts using the Fossomatic method and California Mastitis Test were performed on 1523 goat milk samples taken aseptically at monthly intervals throughout lactation from three goat herds. Of the goat udders, 81·4% were infected, minor pathogens being the most frequent isolates (65·7%). Differences in the level of infection by minor pathogens were found betwccn herds. Cell counts were influenced by stage of lactation and intramammary infection. Cell counts < 106 cells/ml were found in 80% of milk samples infected by major pathogens and in 45% infected by minor pathogens. About 81% of udders infected with major pathogens gave California Mastitis Test scores of 2 and 3, compared with 20% for uninfected goats. A high proportion (65%) of udders infected with minor pathogens also produced scores of 2 and 3. A significant positive correlation was found between the California Mastitis Test and cell counts. The use of cell counts for the detection of abnormal goat milk is discussed.