Biofilms and efflux pump regulatory gene (mexR) in multidrug-resistant Pseudomonas aeruginosa isolated from migratory birds in Egypt

Background and Aim: Multidrug-resistant (MDR) Pseudomonas aeruginosa is a global threat to public health. This study aimed to determine biofilms and efflux pump regulatory gene (mexR) in MDR P. aeruginosa isolates. Materials and Methods: A total of 42 fecal samples of aquatic migratory birds collected during hunting season in Egypt were evaluated for the detection of P. aeruginosa according to standard culture-based methods. The antibiotic susceptibility of P. aeruginosa strains was evaluated using disk diffusion methods. The biofilm formation ability of the isolates was phenotypically determined using a colorimetric microtitration plate assay. Polymerase chain reaction amplification was performed to detect biofilm genes (PelA and PslA) and mexR. Results: In total, 19 isolates (45.2%) were recovered from the 42 fecal samples of migratory birds. All isolates were identified as MDR P. aeruginosa, and 78.9% of the strains produced biofilms at different degrees. Molecular detection of biofilm extracellular polymeric substances revealed that PelA was the most predominant gene in the biofilm-producing isolates, followed by PslA. mexR was detected in 63.2% of MDR P. aeruginosa isolates, and its prevalence was higher in non–biofilm-producing strains (75%) than in biofilm-producing strains (60%). Conclusion: Antibiotic resistance in P. aeruginosa isolates recovered from migratory birds through various mechanisms is a major public and animal health problem. It is important to consider the significance of migratory birds in disease transmission.