Multiple secondary outbreaks of NDM-producing Enterobacter hormaechei in the context of endemic NDM-producing Klebsiella pneumoniae.

The increase in E. hormaechei NDM-1 cases in Poland is a consequence of the uncontrolled spread of NDM-1-producing K. pneumoniae genotypes. Several E. hormaechei lineages have acquired NDM-encoding plasmids in different locales which started 'secondary' progressive outbreaks.