The Role of Insertion Sequence (IS) Elements in Inactivation of Outer Membrane Porin OprD and Resistance to Carbapenems among Pseudomonas aeruginosa Clinical Strains in Ardabil

Background & objectives: Carbapenems are the main antibiotics for the treatment of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa). The aims of this study were to determine the prevalence of gene encoding outer membrane porin protein (OprD) in carbapenem-resistant P. aeruginosa strains as well as to assess the role of insertion sequence (IS) elements in the inactivation of OprD porin and the emergence of carbapenem resistance. Methods: In this study, 103 clinical isolates of P. aeruginosa including 58, 42 and 23 strains resistant to imipenem, meropenem, and doripenem were used, respectively. The isolates were collected from patients referred to Ardabil hospitals. The presence of oprD gene and IS elements were investigated using polymerase chain reaction (PCR) and sequencing methods. P. aeruginosa PAO1 standard isolate was used as the positive control strain for oprD gene. Results: The frequency of oprD gene among carbapenem-resistant P. aeruginosa strains isolated from Ardabil hospitals was 96.5%. Furthermore, IS elements were not observed in the investigated isolates. Conclusion: Based on the results of this study, the presence of IS elements did not involve in the inactivation of outer membrane porin OprD and resistance to carbapenems among P. aeruginosa clinical strains in Ardabil. Therefore, an investigation of the role of other mutations in reducing the expression of oprD gene and increasing P. aeruginosa resistance to carbapenems is recommended.