HEMAGGLUTINATION AND ADHERENCE TO PLASTIC BY STAPHYLOCOCCUS-EPIDERMIDIS

Staphylococcus epidermidis is an important nosocomial pathogen responsible for intravenous catheter-related bacteremia and infections of other prosthetic medical devices. We found that the ability of S. epidermidis to hemagglutinate erythrocytes correlated with the adherence of bacteria to plastic and to intravenous catheters. S. epidermidis isolates responsible for prosthetic-valve endocarditis (n = 61) and isolates from intravenous catheters (n = 59) were significantly more likely to cause hemagglutination than isolates from the skin of preoperative cardiac surgery patients (n = 19) (P = 0.027). S. epidermidis isolates (n = 23) recovered from the skin of patients 7 to 10 days after cardiac surgery were significantly more likely to exhibit hemagglutination than the preoperative isolates (P = 0.015). By a quantitative adherence assay, we also observed that the hemagglutination titer and number of species of erythrocytes agglutinated correlated directly with adherence to polystyrene (P < 0.001). In addition, hemagglutinating isolates were significantly more likely to be recovered in high number from intravenous catheters when semiquantitative catheter culture techniques were used (P < 0.001). We speculate that hemagglutinin(s) either plays a direct role in adherence to polymers and thus prosthetic-device infection or serves as an easily demonstrable marker for adherence-prone isolates.