ANTIBIOTICS AND PREVENTION OF MICROBIAL COLONIZATION OF CATHETERS

Slime-producing staphylococci frequently colonize catheters, and when they are embedded in biofilm, they become resistant to various antibio tics, In the study that is described, the comparative efficacies of va ncomycin, clindamycin, novobiocin, and minocycline, alone or in combin ation with rifampin, were tested in an in vitro model of colonization. The model consisted of the modified Robbins device with antibiotic-im pregnated cement filling the lumen of catheter segments, The synergist ic combination of minocycline and rifampin was the most efficacious in preventing bacterial colonization of slime-producing strains of Staph ylococcus epidermidis and Staphlococcus aureus to catheter surfaces, A similar trend was observed when the inhibitory activities of polyuret hane catheters coated with minocycline and rifampin were compared with the inhibitory activities of catheters coated with other antimicrobia l agents, The inhibitory activities of catheters coated with minocycli ne and rifampin against S. epidermidis, S. aureus, and Enterococcus fa ecalis strains, for example, were significantly better than those of c atheters coated with vancomycin (P < 0.05). The inhibitory activities of catheters coated with minocycline and rifampin against gram-negativ e bacilli and Candida albicans were comparable to those of catheters c oated with ceftazidime and amphotericin B, respectively. We found that the combination of minocycline and rifampin is unique and highly effe ctive in preventing the colonization of catheters with slime-producing staphylococci and that it also displays a broad-spectrum inhibitory a ctivity against gram-negative bacteria and yeast cells.