PILLAR C, GILMORE MS; Interscience Conference on Antimicrobial Agents and Chemotherapy (43rd: 2003: Chicago, Ill.).
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2003 Sep 14-17; 43: abstract no. B-818.
Oklahoma University Health Sciences Center (OUHSC), Oklahoma City, OK.
Introduction: Enterococci in the human host exist either as benign commensals within the gastrointestinal tract or as pathogens capable of causing a variety of diseases including bacteremias, infectious endocarditis, and urinary tract infections. Infection with Enterococcus faecalis comprises 65 to 80% of all nosocomial enterococcal infections. The presence of cytolysin, a bacteriocin/hemolysin, is enriched in pathogenic isolates of E. faecalis and is associated with virulence in a variety of infection models. A response regulatory system within E. faecalis designated fsr, which exhibits similarity to the agr quorum-sensing system of Staphylococcus aureus, is responsible for the regulation of serine protease and gelatinase production and has been shown to contribute to virulence. This study was undertaken to determine whether or not fsr affects the expression of cytolysin. METHODS: The effect of fsr on cytolysin expression was assessed using isogenic fsr wild type and mutant strains in which cytolysin was introduced on a pheromone-responsive plasmid. RESULTS: An enhanced zone of hemolysis was observed with the fsr mutant in comparison to wild type suggesting that something regulated by fsr may in fact be adversely affecting cytolysin expression. Further investigation implicated gelatinase, known to be regulated by fsr, in the observed phenotypic variation in hemolysis. Furthermore, gelatinase containing supernatants are active against the structural subunits, CylL[L] and CylL[S], to which cytolytic activity is attributed. CONCLUSIONS: These results demonstrate an apparent antagonism between the gelatinase and cytolysin of E. faecalis, however a role for this antagonism in the pathogenesis of E. faecalis has yet to be determined.
Publication Types:
Keywords:
- Bacteriocins
- Cytotoxins
- Enterococcus
- Enterococcus faecalis
- Gelatinases
- Gene Expression
- Gene Expression Regulation, Bacterial
- Hemolysin Proteins
- Humans
- Membrane Glycoproteins
- Perforin
- Plasmids
- Serine Endopeptidases
- Staphylococcus aureus
- Virulence
- genetics
Other ID:
UI: 102266335
From Meeting Abstracts