Resistance to Antibiotics in Plankton and Biofilm Cultures of Pseudomonas aeruginosa Clinical Strains

Abstract

Biofilms formed by Pseudomonas aeruginosa strains isolated from biomaterial of patients with implant-associated infection are characterized by much higher resistance to antibiotics of various classes than plankton cultures of these strains. The concentrations of antibiotics causing the death of 90% of P. aeruginosa biofilm (MIC 90 ) was 2-6 µg/ml for fluoroquinolones, 267-356 µg/ml for cephalosporins, and 92-215 µg/ml for amikacin, which significantly (p<0.05) differed from MIC 90 for plankton cultures that did not exceed 0.8 µg/ml for fluoroquinolones, 19 µg/ml for cephalosporins, and 3 µg/ml for amikacin. The degree of the microbial biofilm maturity also affected antibiotic resistance.