Biofilm Production in Staphylococcus epidermidis Isolated from Hosocomial Infection / 微生物学通报

ABSTRACT

To determine the relationship between the intercellular adhesion operon (ica) and the biofilm production in Staphylococcus epidennidis isolates from nosocomial infection, and the affection of ica on the antibiotic susceptibility of the isolates, we collected 106 strains, epidermidis isolates from nosocomial infection specimen to detect their biofilm production by quantitative and qualitative method and investigate the existence of ica operon by PCR. The minimal inhibitory concentration (MIC) to erythromycin, ampicillin, cefoxitin, ceftriaxone, teco-planin, ciprofloxacin, tetracycline, trimethoprim-sulfamethoxazole and vancomycin were tested. Among the isolates, 33 (31. 1% ) of them were detected out carrying ica operon. The rate of biofilm production of the ica-posi-tive isolates was higher than that of the ica-negative (P =0. 001) . By adding glucose and NaCl into the culture the detection rate of biofilm production could be increased. The antibiotic susceptibility of the plankton cells of ica-positive isolates to erythromycin, cefoxitin and ceftriaxone , except ampicillin, ciprofloxacin, tetracycline and tremethoprim-sulfamethoxazole, were lower than those of ica-negative isolates. This study showed that the existence of ica operon was close related to the biofilm formation in 5. epidermidis isolates from nosocomial infection. However, the mechanism of antibiotic resistance of the strains inside the biofilm still needed to be illustrated.