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

The aim of the present study was to characterize sporadic cases and an outbreak of NDM-like-producing Enterobacteriaceae recovered from hospital settings, in Czechia. During 2016, 18 Entrobacteriaceae isolates including 10 Enterobacter cloacae complex (9 E. xiangfangensis and 1 E. asburiae), 4 Escherichia coli, 1 Kluyvera intermedia, 1 Klebsiella pneumoniae, 1 Klebsiella oxytoca, and 1 Raoultella omithinolytica 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 E cloacae complex, isolated in 2012, was studied for comparative purposes. All isolates of E. cloacae complex, except the E asburiae, recovered from the same hospital, were assigned to ST182. Additionally, two E coli belonged to ST167, while the remaining isolates were not clonally related. Thirteen isolates carried bla(ND)(M-)(4), while six isolates carried bla(NDM-1) (n = 3) or bla(NDM-5) (n = 3). Almost all isolates carried bla(NDM)-like-carrying plasmids being positive for the IncX3 allele, except ST58 E. coli and ST14 K pneumoniae isolates producing NDM-1. Analysis of plasmid sequences revealed that all IncX3 bla(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 Tn3-like transposon. On the other hand, the ST58 E. coil and ST14 K. pneumoniae 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-beta-lactamase (M beta L), which exhibited high similarity to the mosaic region of pS-3002cz from an ST11 K. pneumoniae from Czechia. Finally, pEsco-36073cz was a multireplicon A/C-2+R NDM-1-encoding plasmid. Similar to other type 1 A/C-2 plasmids, the bla(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 bla(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.