The frequency of broad-spectrum beta-lactamase CTX-M genotypes in Pseudomonas aeruginosa isolated from Kermanshah hospitals (2013-14)

Background: Pseudomonas aeruginosa is one of the most important causes of opportunistic infections. The infection caused by P. aeruginosa is usually severe and life-threatening and its treatment is difficult due to limited susceptibility to antimicrobial agents and acquiring resistance during treatment. The purpose of this study was to determine the prevalence of antibiotic resistance and extended spectrum of beta lactamase (ESBL) genes of CTX-M in the P. aeruginosa isolated from Kermanshah hospitals in 2013-2014.
Methods: A total of 60 isolates of P.aeruginosa were collected from burn wound, urine, lung and other samples from major hospitals of Kermanshah. The antimicrobial susceptibility of isolates was determined using disk diffusion method according to CLSI standards .The CTX-M genes were detected by PCR and the collected data were statistically analyzed.

Results: In this study, the highest and lowest rates of antibiotic resistance were reported for carbenicillin and gentamicin, respectively. The PCR results showed 13 (21.6%), 3 (5%), 2 (3.3%) and 3(5%) isolates contained CTX-M, CTX-M1, CTX-M2 and CTX-M3 genes, respectively.

Conclusion: The results of this study indicated a high antibiotic resistant rate among P. aeruginosa isolates. Moreover, the frequency of CTX-M genes among isolates, in particular the burn wound isolates, is high in Kermanshah and can result in the expansion of resistance in this bacterium.