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

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 bla OXA−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.