Evaluation of Polymyxin B Susceptibility Profile and Detection of Drug Resistance Genes among Clinical Isolates in Tehran, Iran during 2015-2016.

is an important opportunistic pathogen, responsible for approximately 10% of all gram-negative nosocomial infection. The aim of this study was to determine aminoglycoside and quinolone resistance genes and their antimicrobial susceptibility profile in the clinically . In this cross-sectional study, a total of 100 nonduplicative isolates were collected from different clinical samples. Antimicrobial susceptibility test was performed by disk diffusion method. and genes were identified using PCR method. The results of antibiotic susceptibility test showed that polymyxin B was the most effective antimicrobial against . 97%, 95% and 82% of isolates were resistant to cefepime, ceftriaxone, and amikacin, respectively. The molecular distribution of and genes were 45%, 50%, and 50% of isolates, respectively. However, genes could not be detected in any strain This study showed that polymyxin B was the best drug against clinical isolates. This data is also valid for polymyxin E (colistin), which is mostly used in clinics. There is a high level of resistance genes among clinical isolates. This high prevalence rate highlights the necessity for the development of rapid diagnostic assays and continuous monitoring of antibiotic resistance.