Masoumeh Beig - Department of Medical Microbiology, Hamadan University of Medical Sciences, Hamadan, Iran
Mohammad Reza Arabestani - Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
Abbas Maleki - M.S nursing, , Hamadan University of Medical Sciences, Hamadan, Iran

Background and Objective: In recent years, prevalence of Pseudomonas aeruginosa isolates resistant to Carbapenem antibiotics has increased. Therefore, the aim of study was to examine the relationship expression of OprD gene in P. aeruginosa isolates producing MBL and KPC. Materials and Methods: Overall 97 P. aeruginosa strains, were isolated from Hamadan hospitals in 2017-2018. Antibiotic susceptibility testing was performed using disk diffusion and Minimal Inhibitory Concentration (MIC) methods. Carbapenemase production was identified by ECD, MHT and PCR. Expression of OprD gene was mesured by Real-Time PCR. Results: The results showed that the highest resistance was to cefoxitin 92 (94.8%) and the lowest resistance was to piperacillin-tazobactam, 38 (39.2%). Also, 42 (85.7%) isolates had positive MIC results for imipenem. Carbapenemase production was detected in 53.6% and 51% and 50.51% of the isolates with ECD, MHT and PCR tests, respectively. Out of 20 tested isolates, decreased expression of oprD gene was observed in 12 (60%). There was significant relationship the presence of carbapenemase and expression of OprD gene (Pvalue <0.05). Conclusion: High percentage of P.aeruginosa isolates were resistant to Carbapenems,and also there was a significant correlation between expression of OprD gene and presence of carbapenemase.

Pseudomonas aeruginosa, OprD, efflux pump