Mutational analysis of multidrug efflux pump (AcrAB-TolC) in Enterobacter cloacae isolates from clinical samples

In Gram-negative bacterial pathogens, multidrug efflux pump's role is being studied as one of the critical mechanisms to develop antibiotics resistance. The current study was designed to characterize the AcrAB-TolC efflux pump genes to determine its role in multidrug resistance of hospital-acquired Enterobacter cloacae. In this cross-sectional descriptive study, a total of 200 clinical samples were collected for the isolation of E. cloacae in district Peshawar, Khyber Pakhtunkhwa, Pakistan. The isolates were screened for antibiotic sensitivity testing. The molecular tools were utilized for the characterization of efflux pump AcrAB-TolC and its regulator genes with mutational analysis. Total 120 samples were found positive for the existence of multidrug resistant E. cloacae isolates. Nine (09) isolates were found positive for harboring AcrA, AcrB, and TolC genes while the regulator genes (RobA, RamA, and MarA) were detected in all 120 isolates. In AcrA gene (2) silent and (4) missense mutations were found while in AcrB (2) missense and in TolC (6) and in RobA (4) missense mutations were found. No mutation has been reported in the RamA and MarA gene. The mutations detected were novel and affected protein stability. The regulatory factors and efflux pump components of hospital-acquired E. cloacae are crucial in causing resistance to a variety of antibiotics, highlighting their significance as a possible target for innovative antimicrobial tactics.