Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas

Background and Objectives: Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa. Materials and Methods: In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimicrobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed. Results: Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%). Conclusion: The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particularly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.