[Effect of subinhibitory concentrations of beta-lactams on the production of slime, surface hydrophobicity and adhesion of Staphylococcus epidermidis].

The activity of subinhibitory concentrations of oxacillin, imipenem, cefalotin, cefuroxime, cefotaxime and amoxycillin-clavulanic acid upon slime production, surface hydrophobicity and polystyrene adherence of S. epidermidis was evaluated. Slime production and polystyrene adherence of three Staphylococcus epidermidis strains was assessed using test tube (safranin stained film) or in microtiter plate. The surface hydrophobicity was determined using a biphasic system (water/p-xylene). Using one-half and one-quarter of MIC for all antibiotics tested, a reduction in slime production and polystyrene adherence was observed in all three strains used. Regarding surface hydrophobicity, in one of the strains used we have observed a rise in surface hydrophobicity values as compared to control strains whenever one-half of MCI was used for all six antimicrobial agents and also with one-quarter of amoxicillin-clavulanate MCI. Subinhibitory MCI of all six antibiotics tested inhibits slime production and adherence of Staphylococcus epidermidis. This inhibitory effect is not related to changes in surface hydrophobicity.