Virulence genotyping of drug resistant Pseudomonas aeruginosa clinical isolates in Egypt using multiplex PCR

Abstract

Pseudomonas aeruginosa is a serious Gram- negative pathogen capable of causing several nosocomial and community acquired infections. It produces many toxins such as: exotoxin A, pyocyanin, elastase and type III secretion system proteins. P. aeruginosa is genotyped according to the produced type III secretion system protein into invasive and cytotoxic genotypes. This study aimed to determine the prevalent virulence genotypes as well as the prevalence of five virulence genes using multiplex PCR. The antimicrobial resistance of the collected 134 P. aeruginosa isolates was detected using the disc diffusion method. The five exotoxin genes were detected by conventional multiplex PCR. Seventy percent of isolates were multidrug resistant. The phz, lasB, toxA, exoS and exoU genes were detected in 93%, 90%, 88%, 57% and 43% of isolates, respectively. Fifty two percent of isolates represented the invasive genotype and 38.8% represented the cytotoxic genotype. Clinical P. aeruginosa strains exhibit high antimicrobial resistance. The invasive and cytotoxic genotypes are associated with different types of clinical specimens and both genotypes can co-exist in the same isolates. Therefore, following up the antibiotic resistance of P. aeruginosa and its virulence factors and produced toxins is recommended to judge the bacterial virulence in outbreaks and epidemiologic studies.