Evaluation of the relationship between CRISPR-Cas system and virulence and antibiotic resistant genes among carbapenem resistant Klebsiella pneumoniae isolates

Abstract

This study was designed to characterize the CRISPR-Cas systems in carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates and to evaluate the potential association of these systems with antibiotic resistant, biofilm formation, and bacterial virulence. Materials and Methods: A total of 156 CRKP isolates were collected from different specimens of the inpatients. Antimicrobial susceptibility testing and biofilm formation capacity were evaluated using standard methods. Furthermore, eleven carbapenemase genes, the CRISPR-Cas system subtype genes, and seventeen virulence genes were identified using separate standard PCR reactions. The genomic background of isolates was identified by random amplified polymorphic DNA (RAPD)-PCR. Results: There was a significant correlation between the presence/absence of the CRISPR-Cas system and both biofilm formation and antimicrobial susceptibility to some antibiotics among CRKP isolates. PCR analysis of carbapenemase genes revealed that the frequency of carbapenemase gene NDM-1 was significantly higher in the isolates that had subtype I-E CRISPR-Cas system. In addition, the isolates containing subtype I-E CRISPR-Cas system tended to have more virulence genes such as allS, k2A, wcaG, aerobactin, rmpA, iroN, magA, rmpA2, kfu, iutA, iucB, ybtS, repA, and terW.