Molecular detection of biofilm-related genes and antimicrobial resistance patterns in Pseudomonas aeruginosa isolates from Northern Iran.

Pseudomonas aeruginosa is widely recognized as one of the primary opportunistic pathogens responsible for a wide range of nosocomial infections, notably in immunocompromised patients. Antibiotic resistance and biofilm formation, as two major virulence factors of P. aeruginosa, are related to the persistence of prolonged infections. This study was designed to (1) evaluate the frequency of multidrug-resistant (MDR) P. aeruginosa in northern Iran and (2) analyze the frequency of biofilm-associated genes and their correlation with antimicrobial patterns. Clinical samples (n = 80) were collected from ICUs and other wards and processed for the isolation and identification of P. aeruginosa. Antimicrobial susceptibility was assessed using disk diffusion. PCR was performed to target the biofilm-associated genes. Out of 80 P. aeruginosa isolates, the prevalence of isolates was highest in the ICU (57.5%), and sputum was the most common specimen type (37%). Piperacillin/tazobactam demonstrated the highest activity (76.2% susceptible), followed by amikacin (52.5% susceptible). Notably, 45% of the isolates were MDR, 52.5% were XDR, while 2.5% were neither MDR nor XDR. The biofilm-associated genes ppyR and pslA were detected in 92.5% and 87.5% of the isolates, respectively, whereas pelA was found in 85% of the isolates. Among the 59 pelA, ppyR, and pslA-positive isolates, 47.45% were MDR, 42.37% were XDR, and 10.18% were non-MDR/XDR. Based on these outcomes, we strongly recommend strict infection prevention and control strategies to limit the transmission of MDR-PA, particularly in hospital settings. Piperacillin/tazobactam remains relatively effective; however, its administration should be guided by antimicrobial stewardship guidelines.