LAUSR

Background. Biofilm produced from Pseudomonas aeruginosa is the cause of infection induced by contact lenses, trauma and post‐surgery infection. The aim of this study was to evaluate biofilm formation and the presence of the genes ndvB and tssC1 in ocular infection isolates of P. aeruginosa. Methods. A total of 92 P. aeruginosa strains were collected from patients with ocular infection referred to Farabi Hospital between March 2014 and July 2015. Antibiotic susceptibility patterns were evaluated by the agar disc‐diffusion method according to CLSI guidelines. PCR assays were used to detect ndvB and tssC1, genes associated with resistance in biofilm‐producing P. aeruginosa isolates. Biofilm formation ability was examined by crystal violet microtitre plate assay. Results. During the period of study, 92 P. aeruginosa were isolated from ocular infections including keratitis (n=84) and endophthalmitis (n=8). The highest resistance rates were seen against colistin (57.6%) and gentamicin (50%) and the lowest resistance rates were seen against imipenem (3.3%), aztreonam (4.3%), piperacillin‐tazobactam (4.3%), ceftazidime (4.3%) and ciprofloxacin (5.4%). Biofilm production ability was found in 100% of the isolates. PCR assays showed that of the 92 P. aeruginosa isolates, 96.7 and 90.2% harboured the genes ndvB and tssC1, respectively. Conclusions. Our results showed a considerable ability of biofilm production, as well as the occurrence of biofilm‐specific antimicrobial resistance genes (ndvB and tssC1), in P. aeruginosa isolates from ocular infections in Farabi Hospital.