In vitro adherence of Enterococcus faecalis and Enterococcus faecium to urinary catheters

The in vitro adherence of ten strains of Enterococcus faecalis and ten strains of Enterococcus faecium to siliconized latex urinary catheters and to silicone elastomer was evaluated. Bacterial suspensions (2.5x10(5) cfu/ml) in tryptic soy broth containing 0.5 cm segments from each type of catheter were incubated at 37 degrees C. At specified intervals, the segments were washed to remove nonadherent bacteria and sonicated for 1 min, and colony-forming units were quantified. Bacterial adherence occurred rapidly, reaching maximal peaks after 24 h of incubation. Enterococcus faecium adherence to both biomaterials was significantly lower than that of Enterococcus faecalis. No differences were observed between the two elastomers. Bacterial adherence was not related to bacterial surface hydrophobicity, hemolysin or gelatinase production.