Assessment the prevalence and activity of efflux pump encoded system (AcrAB-TolC) and biofilm formation in MDR Klebsiella pneumoniae isolates

Abstract

Multidrug-resistant (MDR) Klebsiella pneumoniae represents a serious public health risk because of its capacity to resist multiple antibiotics. Many virulence factors contribute to this resistance. One of the significant virulence factors is the overexpression of efflux pumps, such as the AcrAB-TolC system. Aim: The study aims to detect the AcrAB-TolC triplet efflux pump genes, as well as to assess efflux pump activity and the production of biofilm in K. pneumoniae isolates after testing their antibiotic susceptibility. Methods: The study included patients of various ages who seek five hospitals in Baghdad, Iraq, from which 150 clinical samples were collected (Urine, blood, sputum, wounds, and burns). Only 50 isolates exhibited characteristics of K. pneumoniae were diagnosed by conventional methods Such as cultures and biochemical tests. Results: The study identified that 80% of K. pneumoniae isolates were multidrug-resistant (MDR), showing complete resistance to ampicillin (100%) and significant resistance to cefotaxime (76%) and ceftazidime (70%), while only 10% resistance was noted for chloramphenicol. The ethidium bromide (EtBr)-agar Cartwheel method confirmed that all isolates exhibited high efflux pump activity (100%). All isolates were biofilm producers to varying extents, as detected via the microtiter plate method. Molecular detection confirmed the presence of the 16S-23S internal transcribed spacer unit and the efflux pump genes AcrAB-TolC in all ten selected isolates (100%). Conclusion: The high prevalence of efflux pump activity and the ubiquitous of efflux genes shows the significant role of these virulence factors for antibiotic resistance across MDR K. pneumoniae isolates