Molecular investigation of exoU and exoY virulence genes in Pseudomonas aeruginosa collected from hospitalized patients in North of Iran: A descriptive-analytical study

Objective: To investigate the frequency of exoU and exoY genes in patients with Pseudomonas aeruginosa infection. Methods: In this study, 100 clinical isolates of Pseudomonas aeruginosa were collected from patients hospitalized in educational- therapeutic hospitals and were identified using standard microbiological tests. Then, the antibiotic resistance pattern of the isolates was determined by the disk agar diffusion method. The bacterial DNAs were extracted by the alkaline lysis method. Finally, the presence of exoU and exoY genes was evaluated by the PCR test. Results: In this study, 47%, 72%, 29%, 39%, 40%, and 44% of the isolates were non-susceptible to piperacillin, aztreonam, ceftazidime, imipenem, tobramycin, and ciprofloxacin, respectively. In addition, 95% and 93% of the clinical isolates carried the exoU and exoY genes. Blood and fecal isolates had both virulence genes, while only one wound isolate had neither genes. Meanwhile, all urinary isolates contained the exoY gene and only one isolate lacked the exoU gene. Also, 88 isolates simultaneously had both exoU and exoY genes. Conclusions: High prevalence of exoU and exoY genes in this region indicates a significant role of type III secretion system in pathogenesis of Pseudomonas aeruginosa. The type III secretion system may be a suitable target to reduce the pathogenicity of this bacterium.