Study on oprD mutation and imipenem resistance in Pseudomonas aeruginosa isolates in Gilan province

Subject Areas : Molecular Microbiology

Hossein  Motahhary Tashi ¹ (M.Sc. student, Department of Biology, Faculty of Basic Sciences, Rasht branch, Islamic Azad University, Rasht, Iran.)
Najmeh  Ranji ² (Assistant Professor, Department of Biology, Faculty of Basic Sciences, Rasht branch, Islamic Azad University, Rasht, Iran.)

Received: 2016-09-26 Accepted : 2016-12-16 Published : 2017-05-22

Keywords: PCR, Pseudomonas aeruginosa, Imipenem, oprD gene,

Abstract :

Background & Objectives: Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen, and one of the mortality causes of nosocomial infections, specifically in patients with severe burns. One of the drug resistance mechanisms in P. aeruginosa is mutation or down-regulation of oprD gene. In this study, we investigated oprD mutations in imipenem-resistant P. aeruginosa isolates in Gilan province. Materials & Methods: In this sectional study, 45 P. aeruginosa strains were isolated from different clinical samples of Rasht and Lahijan hospitals and laboratories. The antibiotic resistance and susceptibility of the strains were determined by Kirby Bauer and minimum inhibitory concentration (MIC) methods. Then, PCR and sequencing were performed to evaluate oprD mutation in imipenem-resistant isolates. Results: 44.4% isolates were imipenem- resistant. The highest resistance was shown to 512 µg/ml of imipenem. Sequencing analysis showed that 5 isolates have T103S and K115T missense mutations in the oprD gene. Furthermore, silencing mutations including L92L were detected in 7 samples, S100S in 7 samples, P116P in 5 samples, and G151G in 3 samples. Conclusion: Since oprD plays, a major role in imipenem entry to the cell, oprD mutation can be the cause of imipenem resistance in P. aeruginosa isolates. Furthermore, the oprD mutation might have changed the affinity to imipenem in these isolates.