ADHESION OF PSEUDOMONAS-AERUGINOSA TO COLLAGEN BIOMATERIALS - EFFECT OF AMIKACIN AND CIPROFLOXACIN ON THE COLONIZATION AND SURVIVAL OF THE ADHERENT ORGANISMS

The adherence of P. aeruginosa to collagen membrane, sponge, and to a new anti-infective COLL dressing and the susceptibility of the organis ms attached to the biomaterials to amikacin were investigated in vitro . After 17 h of attachment, the bacteria demonstrated an increased res istance to amikacin compared with their free-floating counterparts. Am ikacin, even at a concentration exceeding 150 times the minimal bacter icidal concentration (MBC) for the strain tested, did not eradicate th e attached bacteria from the surface of collagen membrane. However, wh en the drug at a high concentration (over 16 times the minimal inhibit ory concentration, MIC) was present in the incubation medium before it had been inoculated with P. aeruginosa, a reduction of 2 log(10) unit s in the organisms adherent to the surface of collagen membrane was ob served. We conclude that slow release of the antibiotic from the COLL dressing could control.ol the bacterial colonization on the surface. I n fact, the released amikacin at the final concentration of 32 times t he MBC reduced the number of adherent bacteria by 6 log(10) units. in contrast, ciprofloxacin at the same final bactericidal concentration c ompletely eradicated the bacteria from the surface of COLL dressing. H owever, as ciprofloxacin is not recommended for use as a topical antim icrobial agent, a further search is needed to find an agent with a sim ilar anticolonization activity. (C) 1998 John Wiley & Sons, Inc. J Bio med Mater Res, 41, 593-599, 1998.