Introduction. Transmission of Enterobacterales in neonatal intensive care units (NICU) can cause outbreaks of colonization and invasive infections among neonates. Two clusters of nosocomial transmission of Klebsiella pneumoniae identified by MALDI-ToF mass-spectrometry were suspected at two NICUs in July and August 2016.Aim. To assess the potential transmission of K. pneumoniae among neonates.Methodology. Whole-genome sequencing (WGS) was performed of K. pneumoniae isolates obtained through targeted surveillance of patients and environmental sampling.Results. WGS data revealed that patient and environmental isolates represented two species, K. pneumoniae and K. variicola. Core-genome multi-locus sequence typing (cgMLST) of the isolates identified three separate transmission clusters, in Hospital A a cluster of K. pneumoniae isolates in 12 children and two environmental samples and a second cluster of K. variicola isolates in five children. In Hospital B a cluster of K. pneumoniae isolates from three children and five unrelated isolates of K. pneumoniae and two unrelated isolates of K. variicola were found.Conclusion. K. variicola can cause hospital outbreaks of colonization and infection similar to other Klebsiella spp.Preliminary results from this study were presented at the 27th European Congress of Clinical Microbiology and Infectious Diseases, April 22-25, 2018, Vienna, Austria.
Keywords: Klebsiella pneumoniae; MALDI-ToF; Whole genome sequencing (WGS); core-genome multilocus sequence typing (cgMLST); outbreak.