| Autor: |
Donelli, Gianfranco, Paoletti, Claudia, Baldassarri, Lucilla, Guaglianone, Emilio, Di Rosa, Roberta, Magi, Gloria, Spinaci, Cinzia, Facinelli, Bruna |
| Zdroj: |
Journal of Clinical Microbiology; August 2004, Vol. 42 Issue: 8 p3419-3427, 9p |
| Abstrakt: |
ABSTRACTBile-resistant bacteria, particularly gram-positive Enterococcus faecalisand Enterococcus faecium, play an important role in biliary stent occlusion, because their sessile mode of growth protects them against host defenses and antimicrobial agents. Twelve E. faecalisand seven E. faeciumstrains isolated from occluded biliary stents have been investigated for slime production, presence of aggregation substance genes, and ability to adhere to Caco-2 cells. Ten isolates were strong producers of slime, and seven isolates produced clumps when exposed to pheromones of E. faecalisJH2-2 and/or OG1RF. The small E. faeciumclumps differed from the large clumps of E. faecalisand were similar to those of E. faeciumLS10(pBRG1) carrying a pheromone response plasmid. After induction with pheromones, the adhesion to Caco-2 cells of clumping-positive strains was found to increase from two- to fourfold. Amplicons of the expected size were detected in three clumping-positive and three clumping-negative E. faecalisisolates by using primers (agg) internal to a highly conserved region of the E. faecalispheromone response plasmids pAD1, pPD1, and pCF10 and primers internal to prgBof the E. faecalisplasmid pCF10. The agg/prgB-positive E. faecalisstrains were also positive in Southern hybridization experiments with a prgB-specific probe. No PCR products were obtained with the same primers from four clumping-positive isolates (one E. faecalisand three E. faeciumstrains), which were also Southern hybridization negative. Our results demonstrate that slime production and pheromone response are both present in isolated enterococci, suggesting that clinical strains with these features might have a selective advantage in colonizing biliary stents. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
