The Association Between Antibiotic Resistance and Virulence Genes in Wound-Isolated Pseudomonas Aeruginosa

Introduction: Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen and a common causative agent of wound infections. Aim: The objective of this study was to assess the prevalence of the toxA and exoU virulence genes in P. aeruginosa isolates obtained from wound infections as well as the patterns of antimicrobial susceptibility and association between these virulence determinants, biofilm formation and antibiotic resistance.

Materials and Methods: This cross-sectional study was performed at Al-Yarmouk Teaching Hospital in Baghdad, Iraq in the period from September 2025 to February 2026. 235 clinical wound samples were collected from patients clinically diagnosed with wound infections. Antimicrobial susceptibility testing and Biofilm formation were done and molecular determination of toxA and exoU genes were conducted by PCR and agarose gel electrophoresis.

Results: 17 isolates (7.23%) of P. aeruginosa were isolated from a total of 235 wound specimens. All the isolates were identified as Gram-negative rods which were oxidase positive and non-lactose fermenters. Ampicillin resistance rates were found raised (94.1%) as well as amoxicillin (88.2%) but higher sensitivities were found for tobramycin (88.2%) and amikacin (76.5%). As a result, 11 isolates (64.7%) were detected to have the multidrug resistance trait. Among those tested, biofilm production was detected in 16 isolates (94.1%), most prevalent was moderate biofilm formation (52.9% of positive profilers). Results: Molecular analysis showed that the toxA gene was positively found in 12 (70.6%) and the exoU gene in 10 (58.8%) isolates.

Conclusions: The P. aeruginosa isolates showed a high level of multidrug resistance, biofilm formation and virulence gene carrier rate.