Regional spread of blaNDM-1-containing Klebsiella pneumoniae Sequence Type 147 in post-acute care facilities

Background Carbapenem-resistant Enterobacterales (CRE) harboring bla KPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point prevalence surveys identified increasing prevalence of bla NDM -containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of bla NDM -producing CRE to understand their regional emergence and spread. Methods We performed whole-genome sequencing on NDM+ CRE isolates from four point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time. Results Genomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an ST147 Klebsiella pneumoniae strain harboring bla NDM-1 on an IncF plasmid. Dated phylogenetic reconstructions indicated that ST147 was introduced into the region around 2013 and likely acquired NDM around 2015. Analyzing genomic data in the context of patient transfer networks supported initial increases in prevalence due to intra-facility transmission in certain vSNFs, with evidence of subsequent inter-facility spread to connected LTACHs and vSNFs via patient transfer. Conclusions We identified a regional outbreak of bla NDM-1 ST147 that began in and disseminated across Chicago area post-acute care facilities. Our findings highlight the importance of performing genomic surveillance at post-acute care facilities to identify emerging threats.