Differences in Antibiotic Susceptibility betweenbiofilm Positive and Biofilm Negative Staphylococcus epidermidis Strains Isolatedfrom Blood Cultures

Overview

The adhering capability and biofilm growth facilitate staphylococcal colonization of surfaces ofdamaged tissues and foreign bodies. Biofilm-forming bacteria are more resistant to immune systemactivities, mechanical effects of blood flow and other adverse effects, e.g. those due to antibiotics.Minimal inhibitory concentrations (MICs) were compared for two groups of Staphylococcus epidermidisstrains isolated from blood cultures. Group 1 included biofilm positive strains whose biofilmformingpotentialwas revealed by both phenotypicand genotypic methods. Group2 included strainswithout biofilm-forming potential. The comparison of MICs for selected antibiotics showed higherresistance of biofilm positive compared to biofilm negative strains. The difference was evidentparticularly for oxacillin, tetracycline, co-trimoxazole and gentamicin.

Key words:
biofilm – antibiotic susceptibility – minimal inhibitory concentration – Staphylococcusepidermidis.