Investigation of Association Between adeA, adeB ,adeI Genes and Phenotypic Activity of Efflux Pump in Multiple Drug Resistant Acinetobacter baumannii Isolates

Acinetobacter baumannii is a major cause of nosocomial infections and is resistant to many antibiotics. Over expression of AdeABC and AdeIJK efflux pumps in Acinetobacter causes resistance to aminoglycosides and decreases the sensitivity of fluoroquinolones. The aim of this study was to investigate the phenotypic activity of the Acinetobacter baumanni isolates associated with presence of adeA, adeB, and adeI genes. The study was performed on 55 strains of A. baumannii isolated collected from specimens of patients hospitalized in Milad Hospital , Tehran. The isolates were diagnosed using biochemical tests and antibiotic susceptibility testing was done by disk diffusion method based on CLSI guidelines. Cartwheel method was used to study phenotypic activity of efflux pump. Multiplex PCR was used to determine the presence of genes. The prevalence of multiple drug resistant isolates was 98%. In terms of efflux pump activity 3.63% isolates were strong, 67.27% moderate and 29.09% were non-active. The frequency of adeA, adeB, adeI genes was 87.2%, 85.4% and 94.5%, respectively. There was significant association between adeA and adeB genes among isolates with actively and non-actively efflux pump. Determination of actively phenotype of efflux pump can determine the multiple drug resistance among A. baumannii isolates. The results confirms the role of main genes encoding AdeABC operon,adeA and adeB in activity of A. baumannii efflux pump.