Secrets of the hospital underbelly: abundance of antimicrobial resistance genes in hospital wastewater reflects hospital antimicrobial use and inpatient length of stay. Secrets of the hospital underbelly: abundance of antimicrobial resistance genes in hospital wastewater reflects hospital antimicrobial use and inpatient length of stay

Hospitals are nodal points for antimicrobial consumption and identification of resistant pathogens and therefore hospital wastewater is a potential major source of AMR. This study uses metagenomics to study how the abundances of resistance genes in hospital wastewater are related to clinical activity within different buildings of the hospital. Sewage was collected over a 24-hour period from multiple wastewater collection points representing different specialties within a tertiary hospital site and simultaneously from community sewage works. High throughput shotgun sequencing was performed using Illumina HiSeq4000. Sequence reads were assigned taxonomically and to the AMR genes in the ResFinder database. The measured AMR gene abundances were then correlated to hospital antimicrobial usage (AMU), other data on clinical activity such as patient/ward characteristics and resistance prevalence in clinical isolates.