Phenotypic and molecular investigation of virulence factors inPseudomonas aeruginosa clinical isolates in Bushehr, Iran

BACKGROUND AND OBJECTIVESPseudomonas aeruginosa is an opportunistic pathogen known as one of the leading causes of nosocomial infections. The pathogenesis of P. aeruginosa includes several virulence factors that enable the bacterium to adapt to a wide range of environments. This study aims to the phenotypic and molecular investigation of virulence factors in P. aeruginosa clinical isolates in Bushehr, Iran.MATERIALS AND METHODSOne hundred and three P. aeruginosa clinical isolates were collected from three hospitals in Bushehr, Iran between October ۲۰۱۷ and June ۲۰۱۹. The isolates were examined for the production of lipase, protease, lecithinase, gelatinase, hemolysin, pigment, DNase, and biofilm. The presence of exoT, exoA, exoY, exoS, exoU, lasB, aprA, algD, plcH, and nan۱ genes were investigated by PCR and sequencing.RESULTS AND DISCUSSIONOne hundred and one (۹۸%) isolates produced protease, lecithinase, hemolysin, and pigment. Ninety six (۹۳.۲%) isolates were gelatinase producers, and ۴۱ (۳۹.۸%) isolates were lipase producers. None of the isolates showed DNase activity. Out of the ۱۰۳ isolates, ۱۰۱ (۹۸%) were biofilm producers, of which ۶۹ (۶۷%) isolates were strong biofilm producers, ۱۶ (۱۵.۵%) isolates were moderate biofilm producers, and also ۱۶ (۱۵.۵%) isolates were weak biofilm producers. Two (۲%) isolates were identified as non-biofilm producers. algD, lasB, aprA, plcH, exoA, and exoY genes were found in ۱۰۲ (۹۹%), ۱۰۱ (۹۸%), ۱۰۱ (۹۸%), ۹۹ (۹۶.۱%), ۹۶ (۹۳.۲%), and ۹۳ (۹۰.۳%) of the isolates, respectively. The frequency of exoT, exoU, exoS, and nan۱ genes was ۷۵.۷%, ۶۲.۱%, ۳۸.۸%, and ۱۷.۵% respectively. The results of our research revealed that the frequency of the isolates producing protease, lecithinase, gelatinase, hemolysin, pigment, and biofilm is high in Bushehr. Most isolates produced strong biofilms. The ability to form biofilm can be related to algD gene.CONCLUSIONThe high prevalence of strong biofilm-producing isolates and related gene in our region emphasizes more attention to overcoming antimicrobial resistance