Molecular Epidemiology of NDM-5-producing Escherichia coli high-risk clones identified in two Italian Hospitals in 2017-2019

Abstract Between November 2018 and October 2019, carbapenem-resistant Enterobacterales carrying New Delhi Metallo-β-lactamase (NDM) caused one of the largest and persistent outbreaks occurred in Italy and intensified surveillance measures have been taken in all Italian hospitals. In this study we analyzed NDM-5- producing Escherichia coli identified in two hospitals of the Lazio region in Italy. Epidemiological and microbiological data demonstrated that in 2018-2019 the NDM-5-producing high-risk E. coli ST167 clone circulated in patients from both hospitals. In 2019, another NDM-5-producing E. coli clone identified by MLST as ST617 was introduced in one of the two hospitals and caused an outbreak. This study describes an application of genomics as a useful method to discern endemic and outbreak clones when applied to strains of the same species (E. coli) with the same resistance determinant (NDM-5) and the relevance of screening patients admitted in critical units for carbapenemase producers to prevent outbreaks.