Correlation between Efflux Pump and Resistance to Antibiotics in Pseudomonas aeruginosa Isolated from Different Clinical Cases

Background: Pseudomonas aeruginosa is an opportunistic bacterium that causes nosocomial infections in hospitals. It can develop high-level multidrug resistance (MDR). The MexA gene is a constitutive chromosomal gene in the Resistance Nodulation Division (RND) family of P. aeruginosa. Objectives: This study aimed to detect the MexA efflux pump resistance gene in P.aeruginosa isolates. Methodology: A total of 165 specimens were collected from patients aged 5-65 years who suffered from burns, wounds, otitis media, and UTIs in two hospitals in Iraq during the period from November 2023 to January 2024. An antibiotic susceptibility test was performed using the Kirby-Bauer disk diffusion method in line with CLSI-2023. Finally, PCR was used to investigate the presence of the MexA gene in (25) P. aeruginosa isolates, which were highly resistant to Beta-lactam and quinolone antibiotics (MDR). Results: Out of 165 specimens, only 116 (70.30%) showed similar morphological traits and biochemical testing for P. aeruginosa. Burn infections showed the highest isolation ratio, followed by wound infections, otitis media, and urinary tract infections (34.54, 17.59, 11.51, and 6.66) % respectively. Antibiotic resistance profile of (25) P. aeruginosa were 100% resistance to Ceftriaxone, Cefotaxime, and Amoxicillin-Clavulanic acid, while only 20% were resistant to Meropenem and Imipenem. MexA gene was found in 96% of P.aeruginosa isolates. Conclusion: The extensive identification of the MexA gene in P.aerogenosa indicates resistance to antibiotics associated with the function of the efflux pump gene and regulatory proteins.