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Full-Text Articles in Pathogenic Microbiology
The Group A Streptococci Bacteriocins Facilitate A Competitive Advantage During Nasopharyngeal Infection, Lana Estafanos
The Group A Streptococci Bacteriocins Facilitate A Competitive Advantage During Nasopharyngeal Infection, Lana Estafanos
Electronic Thesis and Dissertation Repository
Pathogenic streptococci have evolved specific systems to eliminate bacterial competitors within their biological niche. In microbial environments, niche competition is often driven by the production of short antimicrobial peptides called bacteriocins; this provides a mechanism by which Streptococcus pyogenes may compete for ecological stability and establish infection. Recent findings from our laboratory have identified two novel Class IIb bacteriocin systems – Streptococcus pyogenes bacteriocin (Spb) JK and MN in the M18 serotype S. pyogenes strain MGAS8232 – that may contribute to nasopharyngeal infection. Here, we show that galactose and CO2 are distinct regulatory cues which induce antimicrobial activity. Under …
Changes To The Equine Hindgut Microflora In Response To Antibiotic Challenge, Brittany E. Harlow
Changes To The Equine Hindgut Microflora In Response To Antibiotic Challenge, Brittany E. Harlow
Theses and Dissertations--Animal and Food Sciences
Antibiotics are important to equine medicine, but can cause detrimental side-effects including reduced feed intake, allergic reactions, and diarrhea. Antibiotic-associated diarrhea (AAD) is attributed to disruption of the hindgut microflora, permitting proliferation of pathogenic microbes. The objectives were to evaluate the effects of antibiotics on beneficial fecal bacteria, AAD-associated pathogens, microbial species richness and fermentation. Horses were assigned to treatment groups: control (no antibiotics, n=6), trimethoprim-sulfadiazine (oral, n=6), or sodium ceftiofur (IM, n=6). Fecal samples were taken during adaptation (3 wk), antibiotic challenge (1 wk), and withdrawal (1 wk). Fecal cellulolytics decreased by >99% during challenge and did not recover …