Detection of T3SS, oprI, aprA, and pvdA Genes in Clinical Isolates of Pseudomonas aeruginosa obtained from Wound Samples

Abstract

Background: Pseudomonas aeruginosa employs a varied number o f virulence determinants, predominantly porins, type III secretion system (T3SS), alkaline protease and pigments to manipulate the host to establish infections. These factors contribute significantly to virulence in P. aeruginosa and are worrisome. This study is aimed at identifying the virulence genes in P. aeruginosa isolates from wound swabs of patients at two tertiary hospitals in Osun State, Nigeria. Methods: Altogether , 237 participants consisting of 133 fr o m State Hospital, Osogbo and 104 from General Hospital, Iwo with different types of wounds were enrolled. Swabs from the various wound types were collected, grown on cetrimide agar, and recovered isolates identified using conventional biochemical tests. Chromosomal DNA was extracted by thermal lysis and subjected to polymerase chain reaction using specific primers to affirm biochemical identification and detect the presence of ExoT, ExoS, ExoU, ExoY, oprI, aprA, and pvdA genes. Results: Sixty-one (25.7%) P. aeruginosa isolates were recovered in the study. Based on the different wound types, the highest recovery was from surgical sites of caesarian sections (CS) (37.7%; 23/61) followed by trauma sustained from motorcycle and automobile accidents (36.1%; 22/61) and others wound types (26.2%; 16/71). Fifty-nine of the 61 recovered isolates were successfully amplified by PCR primers that targets P. aeruginosa parugin gene. Of these 59 PCR confirmed P. aeruginosa, the oprI gene was detected in 74.6% (n = 44/59) of isolates ; 18 from Osogbo and 26 from Iwo. No bands were detected for the other genes in all 59 isolates analysed. Conclusion: The prevalence of P. aeruginosa w as highest from surgical sites of caesarian sections, with the rates from Iwo higher than that from Osogbo. Detection of oprL gene in 74.6% of strains is significant as it’s interaction with the peptidoglycan plays a part in the maintenance of the structural integrity of the cell, and may cause infections that impair wound healing.