The prevalence of adeabc encoding genes among acinetobacter baumannii carbapenem resistant clinical isolates.

Shahin Zayeri,1,* Fatemeh noorbakhsh,2 Fahimeh baghbani arani,3

1. Department of Microbiology, Islamic Azad University, Varamin-Pishva Branch, Iran.
2. Department of Microbiology, Islamic Azad University, Varamin-Pishva Branch, Iran.
3. Department of genetic, Islamic Azad University, Varamin-Pishva Branch, Iran.

Abstract

Introduction

Acinetobacter baumannii is the important cause of nosocomial infections worldwide due to its propensity to rapidly acquire resistance determinants to a wide range of antibiotics . the most prevalent a. baumannii multidrug resistance (mdr) determinants include efflux pumps genes, beta-lactamases, integrons, and insertion sequence(is) . in acinetobacter, adeabc operon, the chromosomally encoded pumpes belongs to the rnd -type superfamily that consists of adea (membrane fusion), adeb (multidrug transporter) and adec (outer membrane) genes. the major efflux mechanism associated with carbapenem resistance in a. baumannii that is found in approximately 80% of clinical isolates.the aim of this study was determining the frequency of adea,adeb,adec genes among carbapenem resistant acinetobacter baumannii clinical isolates.

Methods

79 strains of acinetobacter baumannii were isolated from clinical specimens of patients were admitted to hearth tehran hospital and diagnosed by biochemical tests. antibiotic susceptibility of isolates was determined by disc diffusion method. after determining the carbapenem resistance profile, the presence of genes was evaluated by multiplex pcr.

Results

The resistance to antibiotics was at high level. for imipenem and meropenem it was 84.9 % and 91.2%, respectively. the frequency of adea,adeb was similar(96.2% ) and for adec gene the frequency was 91.1 % .there was a significant relationship between imipenem résistance and frequency of efflux pump genes.

Conclusion

Adeabc efflux system may be play a role in imipenem resistance in clinical a. baumannii isolates. it must be mentioned about high level of antibiotic résistance of a. baumannii isolates in hospitals, tehran, iran.

Keywords

A. baumannii, efflux pump, adeabc genes, carbapenem