Molecular Detection of pilA Gene and Antimicrobial Resistance Pattern of Pseudomonas aeruginosa Isolated from Burn Patients

Abstract

Abstract

Background: Pseudomonas aeruginosa is a highly infectious and antibiotic-resistant pathogen and is considered one of the most important opportunistic bacteria associated with burn wound infections.

Aim: The present study aimed to evaluate the antimicrobial-resistance patterns of P. aeruginosa isolates recovered from burn patients in Al-Diwaniyah, Iraq, and to determine the frequency of the pilA virulence gene.

Materials and Methods: A total of 100 burn wound swabs were collected between January and April 2025. Isolation and identification of P. aeruginosa were performed using conventional microbiological and biochemical methods, including growth on cetrimide agar. Antimicrobial susceptibility testing was conducted using the disc-diffusion method in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Molecular detection of the pilA gene was performed using polymerase chain reaction (PCR). Of the 100 clinical specimens examined, 42 (42.0%) yielded P. aeruginosa isolates.

Results: Antimicrobial susceptibility testing demonstrated high resistance rates to several commonly used antibiotics, including ceftazidime and gentamicin (85.7% each), cefepime (71.4%), aztreonam (61.9%), tobramycin (59.5%), and piperacillin/tazobactam (57.1%). A resistance rate of 50.0% was recorded for meropenem, ciprofloxacin, and colistin. Molecular analysis detected the pilA gene in 38 of the 42 isolates (90.5%), indicating its high prevalence among the isolates and its potential role in bacterial adhesion, motility, biofilm formation, and pathogenicity.

Conclusions: The findings demonstrate a high prevalence of multidrug-resistant P. aeruginosa among patients with burn wound infections and highlight the potential contribution of the pilA virulence gene to bacterial pathogenicity. Continuous antimicrobial-resistance surveillance, rational antibiotic use, and strict implementation of infection-control measures are required to limit the spread of resistant and highly virulent P. aeruginosa strains in healthcare settings.