ACTIVITY OF 8 ANTIBACTERIAL AGENTS ON STAPHYLOCOCCUS-EPIDERMIDIS ATTACHED TO TEFLON CATHETERS

The presence of a Teflon catheter had no effect on the in-vitro activi ty of a range of antibacterial agents against slime producing and non- producing Staphylococcus epinermidis strains as determined by a microd ilution assay. The susceptibility of S. epidermidis attached to Teflon catheters for 6, 24 and 48 h was also evaluated. MICs for planktonic and attached bacteria were similar. When bacteria attached to Teflon f or 6 h were used as inocula, MBC values increased 32-8192-fold for the antibacterial agents tested. Similar results were observed when bacte ria attached for 24 and 48 h were used as inocula. The activity of a h igh concentration (16 x MBC) of these antimicrobial agents against S. epidermidis biofilms in Teflon catheters was evaluated; for five slime non-producing strains, the highest reduction (around 99 %) in bacteri al viability was produced by cloxacillin and teicoplanin; for the slim e producers, the highest effect (99.5 % reduction) was shown by amikac in, clindamycin cloxacillin and ciprofloxacin but all cases still show ed bacterial counts higher than 10(3) cfu/catheter segment. It is conc luded that adherence of S. epidermidis to Teflon catheters decreases t he bactericidal activity of the antibacterial agents tested in vitro.