Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of healthcare-associated infection. Reservoirs of VREfm
are largely assumed to be nosocomial although there is a paucity of data on alternative sources. Here, we describe an integrated epidemiological and genomic analysis of E. faecium associated with bloodstream infection and isolated from wastewater. Treated and untreated wastewater from 20 municipal treatment plants in the East of England, United Kingdom was
obtained and cultured to isolate E. faecium, ampicillin-resistant E. faecium (AREfm), and VREfm. VREfm was isolated from
all 20 treatment plants and was released into the environment by 17/20 plants, the exceptions using terminal ultraviolet
light disinfection. Median log10 counts of AREfm and VREfm in untreated wastewater from 10 plants in direct receipt of
hospital sewage were significantly higher than 10 plants that were not. We sequenced and compared the genomes of 423
isolates from wastewater with 187 isolates associated with bloodstream infection at five hospitals in the East of England.
Among 481 E. faecium isolates belonging to the hospital-adapted clade, we observed genetic intermixing between wastewater
and bloodstream infection, with highly related isolates shared between a major teaching hospital in the East of England and
9/20 plants. We detected 28 antibiotic resistance genes in the hospital-adapted clade, of which 23 were represented in
bloodstream, hospital sewage, and municipal wastewater isolates. We conclude that our findings are consistent with widespread distribution of hospital-adapted VREfm beyond acute healthcare settings with extensive release of VREfm into the
environment in the East of England.

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