Upregulation of abeM, amvA, and qacEΔ1 efflux pump genes associated with resistance of Acinetobacter baumannii strains to disinfectants

Abstract

Background and aims: Acinetobacter baumannii is among the most concerning cause of nosocomial infections due to its high level of antibiotic resistance and high mortality. The aim of this study was to determine the role of efflux pumps in resistance of A. baumannii strains to three disinfectants, including MICROZED ID-MAX, NANOSIL D2, and OPIDEX OPA. Methods: Twenty-eight environmental and clinical isolates of A. baumannii were collected from selected hospitals of central Iran. The minimum inhibitory concentrations of the disinfectants were determined and real time reverse transcriptase-PCR was performed to investigate the expression level of qacEΔ1, amvA, abeM, and adeB efflux pump genes. Results: Considering both clinical and environmental isolates, there was a significant difference in the mean expression level of qacEΔ1 gene between susceptible and resistant strains to MICROZED ID-MAX disinfectant, of amvA and abeM genes between susceptible and resistant strains to NANOSIL D2 disinfectant and of abeM gene in susceptible and resistant strains to OPIDEX OPA disinfectant (all P ˂.05). The expression levels of abeM and amvA genes were higher in the environmental isolates that were resistant to NANOSIL D2 disinfectant compared to those that were susceptible (P ˂.05). Conclusions: This study provided evidence for the role of abeM and amvA genes in the resistance of environmental isolates to disinfectants, particularly hydrogen peroxide derivatives.