Evaluation of Antimicrobial Resistance and Production of metalloa-β-lactamases in Clinical Isolates of Pseudomonas aeruginosaIsolated from Tehran, Iran.

Background and Objectives: The rising trend of antibiotic resistance among Pseudomonas aeruginosa strains has become a global concern. The current work was conducted to investigate the prevalence of bla-IMP, bla-VIM, bla-SIM, bla-SPM and bla-NDM metallo-beta-lactamase (MBL) among clinical P. aeruginosa isolates obtained from of different hospitals in Gorgan, Iran. Materials and methods: During a twelve-month period-fromFebruary 2016 to February 2017, 130 Pseudomonas aeruginosa isolates, collected from ShahidMotahari hospital in Tehran. Identification of P. aeruginosa with MBL was done using double disk synergy test (DDST) and polymerase chain reaction (PCR) using specific primers for blaI-MP1, bla-VIM1, bla-SIM1, bla-SPM1 and bla-NDM. Also, the antibiotic susceptibility of all isolates was determined. Results:In this study, cephpodoxim and polimixin with 98.6% and 1.7% resistance showed the highest and lowest resistance against isolates. A total of 130 clinical P. aeruginosa isolates were recovered, of which 32.3% (n=42) were identified as CRPA (carbapenem-resistant P. aeruginosa.).From 42 isolates, 18(42.02%) isolates were metallo-beta-lactamase producer of which 17 isolates (40.4%), 13 isolates (30.9%) and 1 isolate (2.3%) carried blaIMP-1, blaVIM-1 and NDM genes, respectively. Also, 3 (7.1%) isolates carried both of the blaIMP and blaVIM genes simultaneously. Furthermore, none of the isolates carried blaSIM-1 blaSPM-1, genes by PCR assay. Conclusion: Considering the moderate prevalence and clinical importance of MBL-producing isolates, rapid identification of them and use of the appropriate infection control measures are necessary to prevent further spread of infections by these organisms.