Infections caused by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) are on a constant rise and are a noted cause of outbreaks in neonatal intensive read more care units (NICUs).We used whole genome sequencing (WGS) to investigate the epidemiology of consecutive and overlapping outbreaks caused by ESBL-KP in NICUs in three hospitals in close proximity.Clonality of 43 ESBL-KP isolates from 40 patients was determined by BOX-PCR.
Short-read sequencing was performed on representative isolates from each clone.The dominant clones from each NICU were sequenced using long-read sequencing.Bioinformatics methods were used to define multilocus sequence type (MLST), analyze plasmid content, resistomes, and virulence factors.
In each NICU, we found a unique dominant clone (ST985, ST37, and ST35), each belonging to a distinct sequence type (ST), as well as satellite clones.A satellite strain in NICU-2 (ST35) was the dominant strain in NICU-3, where it was isolated four weeks later, suggesting transmission.NICU-1- and NICU-2-dominant strains had blaCTX-M-15 carried on a similar transposable element (Tn3-ISEcp1) but at different locations: on a plasmid il barone wine and on the chromosome, respectively.
We concluded that the overlapping ESBL-KP outbreaks were a combination of clonal transmission within NICUs, possible transposable element transmission between NICUs, and repeated importation of ESBL-KP from the community.