Detection of Efflux Pumps in Carbapenem Resistant Pseudomonas Aeruginosa Isolated from Benha University Hospitals

Abstract

Background: Pseudomonas aeruginosa (P. aeruginosa) infections pose a significant risk to hospitalized patients due to its high prevalence and inherent resistance mechanisms. Efflux pumps, particularly the Mex family, contribute significantly to multidrug resistance (MDR) in P. aeruginosa. Objectives: To detect phenotypic and genotypic efflux pump-mediated antibiotic resistance in P. aeruginosa isolated from patients admitted to Benha University Hospitals. Methodology: This cross-sectional descriptive study was executed on 50 P. aeruginosa strains isolated from different clinical samples of patients admitted to hospitals of Benha University. The isolates underwent identification and antimicrobial susceptibility testing by means of VITEK® 2 compact system. The phenotypic identification of the efflux pumps was done by the Carbonyl Cyanide M-Chlorophenyl Hydrazone test (CCCP Test), followed by identification of different genes encoding efflux pump-mediated carbapenem resistance by PCR assays. Results: from the different clinical samples, P. aeruginosa were isolated mostly from sputum samples (30%), wound swabs (24%) and urine samples (22%). P. aeruginosa isolates exhibited varying sensitivities to tested antibiotics, showing the highest sensitivity to colistin (70%). The Minimum Inhibitory Concentration (MIC) of meropenem and imipenem significantly decreased in the existence of CCCP, indicating efflux pump involvement. PCR results revealed a high prevalence of MexA (72.4%) and MexE (79.3%) genes, correlating well with phenotypic findings. Conclusion: Efflux pumps have a significant function in mediating antibiotic resistance in P. aeruginosa isolates. The correlation between phenotypic and genotypic results, particularly the prevalence of MexA and MexE genes, underscores the importance of efflux pumps in MDR in P. aeruginosa strains from this clinical setting.