Characterization of NDM-Encoding Plasmids From Enterobacteriaceae Recovered From Czech Hospitals

Abstract

The aim of the present study was to characterize sporadic cases and an outbreak of NDM-like-producing <i>Enterobacteriaceae</i> recovered from hospital settings, in Czechia. During 2016, 18 <i>Entrobacteriaceae</i> isolates including 10 <i>Enterobacter cloacae</i> complex (9 <i>E. xiangfangensis</i> and 1 <i>E. asburiae</i>), 4 <i>Escherichia coli</i>, 1 <i>Kluyvera intermedia</i>, 1 <i>Klebsiella pneumoniae</i>, 1 <i>Klebsiella oxytoca</i>, and 1 <i>Raoultella ornithinolytica</i> that produced NDM-like carbapenemases were isolated from 15 patients. Three of the patients were colonized or infected by two different NDM-like producers. Moreover, an NDM-4-producing isolate of <i>E. cloacae</i> complex, isolated in 2012, was studied for comparative purposes. All isolates of <i>E. cloacae</i> complex, except the <i>E. asburiae</i>, recovered from the same hospital, were assigned to ST182. Additionally, two <i>E. coli</i> belonged to ST167, while the remaining isolates were not clonally related. Thirteen isolates carried <i>bla</i>_NDM-4, while six isolates carried <i>bla</i>_NDM-1 (<i>n</i> = 3) or <i>bla</i>_NDM-5 (<i>n</i> = 3). Almost all isolates carried <i>bla</i>_NDM-like-carrying plasmids being positive for the IncX3 allele, except ST58 <i>E. coli</i> and ST14 <i>K. pneumoniae</i> isolates producing NDM-1. Analysis of plasmid sequences revealed that all IncX3 <i>bla</i>_NDM-like-carrying plasmids exhibited a high similarity to each other and to previously described plasmids, like pNDM-QD28, reported from worldwide. However, NDM-4-encoding plasmids differed from other IncX3 plasmids by the insertion of a Tn<i>3</i>-like transposon. On the other hand, the ST58 <i>E. coli</i> and ST14 <i>K. pneumoniae</i> isolates carried two novel NDM-1-encoding plasmids, pKpn-35963cz, and pEsco-36073cz. Plasmid pKpn-35963cz that was an IncFIB(K) molecule contained an acquired sequence, encoding NDM-1 metallo-β-lactamase (MβL), which exhibited high similarity to the mosaic region of pS-3002cz from an ST11 <i>K. pneumoniae</i> from Czechia. Finally, pEsco-36073cz was a multireplicon A/C₂+R NDM-1-encoding plasmid. Similar to other type 1 A/C₂ plasmids, the <i>bla</i>_NDM-1 gene was located within the ARI-A resistance island. These findings underlined that IncX3 plasmids have played a major role in the dissemination of <i>bla</i>_NDM-like genes in Czech hospitals. In combination with further evolvement of NDM-like-encoding MDR plasmids through reshuffling, NDM-like producers pose an important public threat.