Evaluation of Toxigenic Genes in Pseudomonas aeruginosa Isolated from Different Clinical Samples by Multiplex PCR

Background: Pseudomonas aeruginosa is a gram negative and opportunistic pathogen bacterium which causes several acute and chronic infections involving multiple organs such as urinary tract, skin (burn, surgery) and respiratory system. This organism has multiple virulence factors, which may have a role in pathogenicity. Exotoxin A, elastase, pyocyanin and type III secretion system are the most important virulence factors of P. aeruginosa. The aim of this study was the evaluation of five significant exotoxin genes including exoU, exoS, phzM, toxA and lasB and one internal control gene ecfX in P. aeruginosa.Methods: One hundred clinical isolates of P. aeruginosa were collected from different clinical samples. After phenotypical confirmation, genotype of the strains confirmed by using 16S rDNA and ECF primers. The presence of exoU, exoS, phzM, toxA and lasB genes have screened by multiplex PCR. The data were analyzed statistically by SPSS software.Results: The results of mPCR indicated that internal control gene (ecfX) was present in all of the isolates. The prevalence of exoU, exoS, phzM, toxA and lasB genes were 32%, 92%, 98%, 98% and 99%, respectively. According to the presence of exoU gene, there was significant difference (P< 0.001) between prevalence of P. aeruginosa isolates from skin to others. In addition, isolates from blood had no exoU gene which there was a significant association to the other isolates (P= 0.04).Conclusion: The present study revealed that these virulence genes are present in the majority of isolates with the exception of gene exoU, which showed low prevalence.