Endemic dissemination of different sequence types of carbapenem-resistant Klebsiella pneumoniae strains harboring bla NDM and 16S rRNA methylase genes in Kerman hospitals, Iran, from 2015 to 2017.

Background: The emergence and spread of Klebsiella pneumoniae strains resistant to multiple antimicrobial agents are considered as a serious challenge for nosocomial infections.

Methods: In this study, 175 nonrepetitive clinical isolates of K. pneumoniae were collected from hospitalized patients in Kerman, Iran. Extended-spectrum β-lactamases (ESBLs), AmpC, and carbapenemase-producing isolates were recognized by phenotypic methods. The resistance genes including efflux pumps oqxA/oqxB, 16S rRNA methylase, ESBL, AmpC, and carbapenemase were detected by PCR-sequencing method. Molecular typing was performed by enterobacterial repetitive intergenic consensus-PCR and multilocus sequence typing methods among bla NDM-positive isolates.

Results: Thirty-seven (21.14%) isolates along with sequence types (STs): ST43, ST268, ST340, ST392, ST147, and ST16 were harbored bla NDM. ST43 in 2015 and ST268 during 2016-2017 were the most frequent STs among New Delhi metallo-beta-lactamase (NDM)-positive isolates. We found the distribution of some isolates with bla NDM, bla CTX-M, bla SHV, bla OXA, bla TEM, bla CMY, rmtC, and oqxA/oqxB. Enterobacterial repetitive intergenic consensus-PCR represented seven clusters (A-G) plus four singletons among NDM-positive isolates. This study provides the first report of bla NDM-1-positve K. pneumoniae along with ST268 as well as the spread of nosocomial infections with six different STs harboring bla NDM-1 and other resistance genes in hospital settings especially neonatal intensive care unit.

Conclusions: The dissemination of various clones of NDM-producing K. pneumoniae can contribute to increase the rate of their spread in health care settings. Therefore, molecular typing and detection of resistance genes have an important role in preventing and controlling infection by limiting the dissemination of multidrug-resistant isolates.