Molecular detection of virulence and carbapenem resistance genes in clinical isolates of Pseudomonas Aeruginosa from Iraqi hospitals

Abstract

Objective: This study aimed to assess the molecular prevalence of six key resistance and virulence genes, toxA, oprL, KPC, vim2, hlyA, and vanB2, in Pseudomonas aeruginosa isolates obtained from clinical sources in selected Iraqi hospitals.

Methods: A total of 200 clinical specimens were collected from three hospitals in Iraq. Of these, 25 isolates were confirmed as P. aeruginosa based on culture and biochemical identification. All 25 isolates were subjected to polymerase chain reaction (PCR) to detect the six target genes. PCR amplification products were analysed by gel electrophoresis. Statistical associations between gene presence and sample sources were evaluated using chi-square tests.

Results: All 25 isolates tested positive for toxA and oprL, indicating their ubiquity and potential utility as diagnostic markers. The KPC gene was detected in 84% (21/25) of the isolates, highlighting a high prevalence of carbapenem resistance. No amplification was observed for vim2, hlyA, or vanB2 in any of the isolates. Significant associations were found between gene presence and hospital or specimen source (χ² = 136.52, p < 0.00001).

Conclusion: The detection of KPC alongside the universal presence of toxA and oprL genes underscores the clinical importance of these markers in Iraqi hospital settings. The absence of vim2, hlyA, and vanB2 may reflect regional genomic patterns. These findings emphasise the need for molecular diagnostics, enhanced infection control, and ongoing antimicrobial resistance surveillance to inform treatment protocols and policy.