DETECTION OF AMINOGLYCOSIDE AND QUINOLONE RESISTANCE GENES AND EVALUATION OF POLYMYXIN B SUSCEPTIBILITY PROFILE IN ACINETOBACTER BAUMANNII CLINICAL ISOLATES IN TEHRAN, IRAN DURING 2015-2016

ABSTRACT Acinetobacter baumannii is an important opportunistic pathogen, responsible for approximately 10% of all gram-negative nosocomial infection. The main aims of this study were to detect aminoglycoside and quinolone resistance genes among clinical isolates of A. baumannii and determine the antimicrobial susceptibility profiles. Current study was performed from February 2015 to April 2016, at two teaching hospitals. One-hundred A. baumannii isolates were collected from different clinical samples. Antimicrobial susceptibility tests were done by disk diffusion method according to CLSI guidelines. Detection of the qnrA, anrB, qnrS, aac(3)-IIa, and aac(6′)-Ib genes was done by PCR assay. The results of antibiotic susceptibility tests indicated that polymyxin B was the most effective drug against isolates of A. baumannii and the isolates were most resistant to cefepime (97%), ceftriaxone (95%), and amikacin (82%). The aac(3)-IIa, aac(6′)-Ib, and qnrA genes were found in 45%, 50%, and 50% of isolates, respectively. However, qnrB and qnrS genes could not be detected in any A. baumannii isolate.This study showed that there is a high level of resistance genes among clinical isolates of A. baumannii circulating in hospitals in Iran. This high prevalence rate highlights the necessity for establishing rapid diagnostic assays, more antimicrobial susceptibility tests, continuous antibiotic resistance monitoring. Keywords: Acinetobacter baumannii, Aminoglycoside, Quinolone, Ira