Outbreak of NDM-1-Producing Klebsiella pneumoniae in a Dutch Hospital, with Interspecies Transfer of the Resistance Plasmid and Unexpected Occurrence in Unrelated Health Care Centers

Abstract

In the Netherlands, the number of cases of infection with New Delhi metallo-beta-lactamase (NDM)-positive <i>Enterobacteriaceae</i> is low. Here, we report an outbreak of NDM-1-producing <i>Klebsiella pneumoniae</i> infection in a Dutch hospital with interspecies transfer of the resistance plasmid and unexpected occurrence in other unrelated health care centers (HCCs). Next-generation sequencing was performed on 250 carbapenemase-producing <i>Enterobacteriaceae</i> isolates, including 42 NDM-positive isolates obtained from 29 persons at the outbreak site. Most outbreak isolates were <i>K. pneumoniae</i> (<i>n</i> = 26) and <i>Escherichia coli</i> (<i>n</i> = 11), but 5 isolates comprising three other <i>Enterobacteriaceae</i> species were also cultured. The 26 <i>K. pneumoniae</i> isolates had sequence type 873 (ST873), as did 7 unrelated <i>K. pneumoniae</i> isolates originating from five geographically dispersed HCCs. The 33 ST873 isolates that clustered closely together using whole-genome multilocus sequence typing (wgMLST) carried the same plasmids and had limited differences in the resistome. The 11 <i>E. coli</i> outbreak isolates showed great variety in STs, did not cluster using wgMLST, and showed considerable diversity in resistome and plasmid profiles. The <i>bla</i>_NDM-1 gene-carrying plasmid present in the ST873 <i>K. pneumoniae</i> isolates was found in all the other <i>Enterobacteriaceae</i> species cultured at the outbreak location and in a single <i>E. coli</i> isolate from another HCC. We describe a hospital outbreak with an NDM-1-producing <i>K. pneumoniae</i> strain from an unknown source that was also found in patients from five other Dutch HCCs in the same time frame without an epidemiological link. Interspecies transfer of the resistance plasmid was observed in other <i>Enterobacteriaceae</i> species isolated at the outbreak location and in another HCC.