Antimicrobial resistance gene and pathogen burden in sinks in UK hospitals and associations with healthcare-associated infections, sink design and sink usage: a multi-centre prospective sampling study (The “SinkBug” Project)

Project status:

Last updated 16th June 2022.

*Currently closed to further site participation – thank you to everyone who has expressed an interest and joined the study team so far*

We are seeking expressions for interest for participation in this study with a plan to finalise the network of participating sites and provide training for the study in the final quarter of 2022. The sink sampling period is planned for early 2023. We hope to recruit 30-40 participating sites who:

  • Are able to sample 10 ward sink p-traps (from a medical, surgical and critical care unit) using a standardised protocol during a two-week sampling window; standardised sampling packs and training videos will be provided
  • Can use rapid, dipstick-based (like a urine dipstick) testing to characterise simple biochemical features/antibiotic concentrations in the sink p-trap water and associated tap water outlets for each sink
  • Will photograph the sampled sinks
  • Will return the p-trap samples to the coordinating centre at the University of Oxford for metagenomic sequencing; kits for sample return will be provided 
  • Can collect information on local sink cleaning protocols and local, aggregate, ward-level infection data (only where feasible) for the sampled wards before and after the sampling period
  • Will upload the collected metadata to a custom-designed, standardised database.

Please see below for links to our project protocol. No ethics is required, as this project requires environmental sampling only and any information on infections that is collected will be anonymous and aggregated at the ward/hospital-level.


A UK-wide survey of sink drains in UK hospitals, using genomics to evaluate the taxonomic and antimicrobial resistance (AMR) gene distributions in these settings, and investigating associations with: 

  • Infection-associated data derived from national surveillance datasets, and from local, aggregate ward-level data where this is available
  • Sink design, water characteristics and infection prevention and control interventions, including cleaning protocols at each site. 


Healthcare-associated infections, especially those caused by antimicrobial-resistant Gram-negative bacilli (e.g. Enterobacterales, Pseudomonas aeruginosa) represent a major cause of morbidity and mortality in the UK and other settings. Marked regional difference in the prevalence of these infections and in antimicrobial resistance occurs. 

Hospital sink drains, p-traps and other wastewater sites may represent a sentinel site for the dissemination of AMR mechanisms and “high-risk” bacterial species in hospitals in the absence of dedicated screening programs. Several single-centre studies have shown associations between drain-level and patient-associated AMR/pathogen burden, but typically these have been evaluating only a few gene mechanisms or species.

Sinks and drain sites in healthcare settings are also potentially significant contributors to healthcare-associated infections, as has been evidenced by a number of observational and interventional studies, where sink/drain-related interventions such as decontamination or removal have resulted in a lower incidence of Gram-negative infections and/or terminations of clonal outbreaks. 

Information on whether pathogen and AMR burden in sinks is associated with infection burden in patients could inform surveillance strategies. The impact of sink design features and sink usage on the development of pathogen burden and AMR in these niches could be useful in designing interventions (e.g. modified sink design, specific cleaning protocols) to prevent pathogen dissemination and AMR gene selection.


Any infection doctor, infection prevention and control team member, junior doctor or medical student with an interest in infection specialties. Investigators who have made a significant contribution to sampling/data collection at each centre will be eligible for authorship on the manuscript written by the project leads at the end of the audit. All participants will also be encouraged to network within this collaborative; there may be training opportunities to undertake online analysis of genomics data generated for each site. 


Sites will be invited to express interest from April 2022.

Please express your interest by emailing

Project Documents

The Protocol is available here.

Principal investigators

Dr Nicole Stoesser (lead)

Consultant in Infection/NIHR Oxford BRC Senior Research Fellow

Oxford University Hospitals NHS Foundation Trust/University of Oxford

Prof Sarah Walker 

Professor in Epidemiology/Biostatistics

University of Oxford

Dr Matthew Ellington

Principal Clinical Scientist

UK Health Security Agency (UKHSA)

Dr Ginny Moore

Senior scientist 

UK Health Security Agency (UKHSA)

Dr Paz Aranega Bou

Postdoctoral research scientist

UK Health Security Agency (UKHSA)

Dr Gillian Rodger

Senior research scientist

University of Oxford

Mr Kevin Chau

Senior research scientist

University of Oxford