OXA-10 and OXA-2 ESBLs among multidrug-resistant Pseudomonas aeruginosa isolates from North West of Iran

Production of Extended spectrum β-lactamases (ESBLs) is a common mechanism of resistance in multidrug- Pseudomonas aeruginosa, but the frequency of different ESBLs may vary significantly in different parts of the world. The aim of this study was to investigate the prevalence of OXA-2/OXA-10 type ESBLs and class 1 integron among clinical isolates of P. aeruginosa in Tabriz, North West of Iran. A total of 110 P. aeruginosa isolates was entered in the study. Antibiotic susceptibility was determined by disk diffusion method. Production of ESBL was confirmed by combined disc method, and polymerase chain reaction was used for detection of OXA-2/OXA-10 beta-lactamases and class 1 integrons. Antibiotic susceptibility tests revealed that the highest resistance rate was against aztreonam (82%) and cefepime (77.3%), whereas the highest susceptibility was to imipenem (71%), meropenem (66.4%) and piperacillin/tazobactam (37.3%). In combined disc test, 68 isolates (61.8%) were ESBL producers. PCR analysis showed that 47 (42.7%) isolates carried class 1 integron, among them 22 (32.3%) contained blaOXA-10 and 7 (10.3%) contained blaOXA-2 genes. In conclusion, high prevalence of OXA-10 and OXA-2 type ESBLs were detected in the study region and that imipenem and meropenem were the most active agents against P. aeruginosa isolates.