Study the Role of the Efflux Pump in Multidrug-Resistant Acinetobacter baumannii

Abstract

Thirty-one A. baumannii isolates were obtained from Shar and Burn hospitals in Sulaimani City, KRG-Iraq. Bacterial identification was confirmed by detecting both 16S rRNA and blaOXA-51 genes. The detection of carbapenem resistant isolates was carried out using Kirby- Bauer, RAPDEC Carba NP and combined disc assays. A high rate of drug resistance was observed, as 74.2% of the isolates were multidrug-resistant (MDR) and 38.7% were extensively drug-resistant (XDR), while carbapenem-resistant A. baumannii (CRAB) comprised approximately 58% of the isolates. Among CRAB isolates, carbapenemase production was detected by using the RAPDEC Carba NP and the combined disc assays in 88.8% (16/18) and 55.5% (10/18) of the isolates respectively. Phenotypic activity of efflux pump was detected among 22.5% of all isolates and 38.8% of CRAB isolates.  PCR successfully identified the adeA, adeB, adeC, adeR, and adeS genes in 83.9%, 90.3%, 58%, 80.6%, and 90.3% of the isolates, respectively. Eight mutations in adeR and 15 mutations in adeS regulatory genes were recorded. We conclude that carbapenem resistance mechanisms in A. bumanni isolates included mutations in adeRS regulatory genes and production of carbapenemase.