Molecular epidemiology and mechanisms of antimicrobial resistance in Pseudomonas aeruginosa isolates causing burn wound infection in Iran

Abstract

In this study, the contributions of different resistance mechanisms in Pseudomonas aeruginosa isolates were investigated among burned patients. The real-time reverse transcription polymerase chain reaction was performed to determine the expression level of mexY, ampC, and oprD for isolates. Also the isolates were typed by multilocus sequence typing (MLST). Seventy-five per cent of clinical isolates were multidrug resistant. The bla_{OXA group-I} and bla_PER alleles were identified in 28 and 10 P. aeruginosa isolates, respectively. The majority of bla_PER positive isolates belonged to the same MLST clone and was identified as ST235. The types of remaining isolates were ST360 and ST861. Among 10 bla_PER positive isolates, eight isolates demonstrated reduced oprD expression and mexY overexpression. Our data further highlight the epidemic potential of the international clone ST235. According to the results, different resistant mechanisms identified among ST235 isolates that were resistant to ceftazidime, imipenem, ciprofloxacin, and amikacin.

Keywords:

• MexXY
• MLST
• PER
• Pseudomonas aeruginosa
• ST235

Acknowledgements

We acknowledge Dr Kyungwon Lee from the Department of Laboratory Medicine, Yonsei University College of Medicine Seoul, Korea, for kindly providing bla_IMP-positive P. aeruginosa isolate as a gift. We would also like to thank Dr Fereshteh Shahcheraghi from the Department of Bacteriology, Pasteur Institute of Iran, who gave us two plasmids that contain bla_VIM and bla_PER genes. This work was supported by a grant from Isfahan University of Medical Sciences.