Frequency of Type Iii Secretion System Cytotoxins -Encoding Genes Among Pseudomonas Aeruginosa Isolated From Burn Patients



Khoramrooz SS¹ ; Rahbari N² ; Parhizgari N³ ; Sharifi A¹ ; Yazdanpanah M⁴ ; Gharibpour F⁵ ; Rabani SM⁶ ; Malekhosseini SAA⁷ ; Marashifard M⁷ Show Affiliations
Source: Journal of Zanjan University of Medical Sciences and Health Services Published:2015

Abstract

Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial burn infections. Disease results from the production of numerous virulence factors, some of which are injected directly into the eukaryotic host cells via the type III secretion system (T3SS).The aim of this study was to determine the prevalence of cytotoxins encoding exoT, exoY, exoS and exoU genes among the P. aeruginosa isolated from burn patients. Materials and Methods: Over one year period of study, a total of 95 isolates of P. aeruginosa were collected and identified from burn infections in hospitalized patients. Polymerase chain reaction (PCR)-based method was used for detection of exoT, exoY exoS and exoU genes. According to CLSI (Clinical Laboratory Standards Institute) guidelines antimicrobial susceptibility testing was performed by disc diffusion method against 10 antibiotics. The data were analyzed by χ 2 test. A p value of <0.05 was considered as statistically significant. Results: All of the isolates of P. aeruginosa contained exoT gene while exoY gene was detected in 69.5 % of isolates. The prevalence of exoU and exoS genes was 44.1% and 35.8%, respectively. 8.42% of isolates harbored all of the four genes. Coexistence of exoS and exoU was seen in 10.5% of the isolates. High resistance rates were seen for cefipime, Azteronam and Ofloxacin. Conclusion: Considering the low prevalence of exoS in P. aeruginosa causing burn infection in comparison with other infections caused by this bacterium, it seems that this gene has a minor role in the P. aeruginosa pathogenesis isolated from burn infection. Instead, exoT and exoY were found in nearly all isolates and probably, these genes may have a greater role in burn infections. © 2017, Zanjan University of Medical Sciences and Health Services. All rights reserved.