Emergence of co-existence of blaNDM with rmtC and qnrB genes in clinical carbapenem-resistant Klebsiella pneumoniae isolates in burning center from southeast of Iran

Dissemination of carbapenemase-producing Klebsiella pneumoniae along with 16S rRNA methyltransferase (16S-RMTase) has been caused as a great concern for healthcare settings. The aim of this study was to investigate the prevalence of resistance genes among K. pneumoniae isolates. During October 2015 to February 2016, 30 non-duplicative K. pneumoniae strains were isolated from clinical specimens in a burn center in Kerman, Iran. Antibiotic susceptibility tests of isolates, carbapenemase, extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamase-producing isolates were determined by phenotypic methods. The beta-lactamase, oqxA/B efflux pumps, qnr A, B, S, 16S-RMTase (rmt A, B, and C), and mcr-1 resistance genes were determined by PCR. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used for molecular typing. According to our findings, tigecycline has been shown the most active agent against K. pneumoniae isolates. Antibiotic resistance genes, bla(TEM-1), bla(SHV-12), bla(CTX-M-15), bla(CTX-M-2), bla(NDM-1), bla(FOX), bla(MOX), bla(EBC), bla(ACC), bla(CIT), rmtC, qnrB, qnrS, oqxA, and oqxB, were detected in 11 (36.7%), 13 (43.3%), 11 (36.6%), 5 (16.6%), 9 (30%), 1 (3.3%), 1 (3.3%), 1 (3.3%), 1 (3.3%), 2 (6.7%), 1 (3.3%), 9 (30%), 2 (6.7%), 18 (60%), and 13 (43.3%) of isolates, respectively. The bla(NDM-1) with rmtC was simultaneously observed in one isolate. ERIC-PCR results revealed 25 distinct patterns in eight clusters (A-H) and five singletons. This study highlights the high prevalence of bla(NDM) and emergence of rmtC among carbapenem-resistant K. pneumoniae. The resistance genes are often co-located on the conjugative plasmids, so it might be the reason of the rapid spread of them. The prevalence of multidrug-resistant K. pneumoniae isolates limits the available treatment options and presents tremendous challenges to public health.