Genotypic characterization and detection of resistance mechanisms in carbapenem- resistant Klebsiella pneumoniae isolated from four tertiary care hospitals in Iran

Abstract

Abstract Background The global emergence of genes responsible for carbapenemases and the production of mcr in Klebsiella pneumoniae isolates pose a serious threat to public health. The study of carbapenem and colistin resistance (CLR) in K. pneumoniae has a high priority for the infection control committee. The purpose of this study was to determine the antimicrobial resistance rate and evaluate the pattern of CLR in carbapenem-resistant K. pneumoniae (CRKP) isolated from four tertiary care hospitals in Iran, as well as to describe the clonal relationship of multidrug-resistant K. pneumoniae strains. Fifty clinical isolates of CRKP were obtained from four hospitals in Iran. The mcr-harboring isolates and carbapenemase-encoding genes were screened by PCR amplification, and molecular typing (PFGE) was used to assess their spread. Among the total isolates, 38% were identified as CLR by colistin disk elution. Results Among positive isolates for carbapenemase genes, the most frequent gene was blaOXA−48. Additionally, the mcr-1 gene was detected in 6% of the obtained isolates; none of the other mcr genes were detected in the studied isolates. All isolates were grouped under four clusters (A-D). The major cluster was related to the C cluster with 23 isolates. Conclusions The prevalence of CLR K. pneumoniae was estimated to be 18% in our ICU. Colistin-resistant CRKP is becoming an emerging threat in ICU settings, limiting further treatment options. Additionally, we observed a common molecular signature among CRKP isolates. Therefore, hospitals need to implement an effective infection control system to prevent the outbreak of diverse carbapenem- and colistin-resistant isolates in the future.