show Abstracthide AbstractThis study by the TRACE (Tracking Carbapenemase-producing Enterobacteriaceae) Investigators' Group (Manchester hospitals; University of Oxford; Public Health England) investigated environmental and patient blaKPC-Enterobacterales diversity using systematic regular sampling of 349 wastewater-associated environmental sites across six wards, and corresponding carbapenem-resistant isolates from a subset of patients that were admitted to these wards over the study timeframe. To evaluate within-niche diversity, up to five isolates from each niche were sequenced at any given sampling timepoint.