Detection of ExoS and Las B virulence genes in Pseudomonas aeruginosa isolates from burn patients by PCR in Duhok, Iraq

Abstract

Introduction: Pseudomonas aeruginosa is a common cause of nosocomial infection in both immunocompetent and immunocompromised individuals. It exhibits innate resistance to a wide range of antibiotics and threatens global public health as a silent pandemic.

Methodology: From September 2024 to March 2025, 120 clinical specimens were collected from patients with infected burns of both genders and various ages at the Burn hospital in Duhok city, Iraq. The obtained Pseudomonas aeruginosa isolates were used for the molecular characterization of the virulence genes, the ExoS and Las B, by Polymerase Chain Reaction (PCR).

Results: The overall prevalence of Pseudomonas aeruginosa was 37.5% (45/120), with a significantly higher rate among females than males (45.7% vs 26%). Furthermore, the highest rate of infection (55%) was among ages of > 20-30 years, while the lowest rate, 12.5% was among ages of < 1-10, with a highly significant difference (p = 0.001). All of the examined isolates were 100% (22/22) positive for Exo S and 95.5% (21/22) for Las B genes.

Conclusions: This study underscores the high prevalence of these virulence genes among the Pseudomonas aeruginosa isolates from infected burns, indicating their clinical and epidemiological significance. Additionally, their phylogenetic relatedness highlights their pathogenic potential and role in the international dissemination of virulent lineages.