We studied the effect of subbacteriostatic azithromycin concentrations on the formation of microbial biofilms by Pseudomonas aeruginosa strains that caused implant-associated infection of large joints. Azithromycin in subinhibitory for planktonic cells concentrations 0.01-0.02 μg/ml stimulated biofilm formation by both clinical and reference P. aeruginosa strains, while in concentrations of 1 μg/ml and higher completely inhibited the growth of both reference and clinical plankton P. aeruginosa strains, but stimulated biofilm formation. Increasing azithromycin concentration to 10 μg/ml led to inhibition of P. aeruginosa biofilm growth.
Keywords: Pseudomonas aeruginosa; azithromycin; microbic biofilms; replacement arthroplasty.