Impact of Ciprofloxacin Stress on oqxAB Efflux Pump Gene Expressionin Clinical Isolates of Klebsiella pneumoniae

Background: Multidrug efflux pumps significantly contribute to bacterial resistance to antimicrobial drugs. The oqxAB efflux pump gene in Klebsiella pneumoniae has been well studied due to its significant contribution to antibiotic resistance. Objectives: This study investigated how Ciprofloxacin at a sub-Minimum Inhibitory Concentration (sub-MIC) affected the expression of the oqxAB efflux pump gene in an isolate of Klebsiella pneumoniae that was MDR (Multidrug-Resistant) with strong biofilm-forming ability. Methodology: Clinical samples were collected from blood, wounds, respiratory infections, and urine for isolation of K. pneumoniae. The isolates were tested for antibiotic susceptibility. Then, the MDR with strong biofilm-forming ability K. pneumoniae isolate were selected and incubated with sub-MIC of ciprofloxacin at early, mid, and late stages of the logarithmic growth phase. The levels of expression of the oqxAB efflux pump genes were then quantified by RT-qPCR. Results: Thirty K. pneumoniae isolates were identified from clinical specimens and tested for antibiotic susceptibility. Exposure of multidrug-resistant, strong biofilm-forming isolate to a sub-MIC of Ciprofloxacin resulted in marked downregulation of efflux pump genes. OqxA expression decreased by 0.3-fold, 0.09-fold, and 0.0001-fold at the early, mid, and late logarithmic phases, respectively, while OqxB expression decreased by 0.08-fold, 0.05-fold, and 0.004-fold at the corresponding stages. Conclusion: The results highlight the significant impact of ciprofloxacin stress in suppressing the expression of the oqxAB efflux pump genes.