Water Sources Highlight A Patient Care Gap

Clinical handwash basins, healthcare sinks and showers along with their u-bends and wastewater drains are not addressed as infection sources.  The plethora of recently published waterborne infection data has not been translated into meaningful improvements in patient or environmental surveillance, remediation within Water Safety Groups, nor have training materials to essential supporting services, including Plumbers and Housekeeping Teams, been updated or delivered.  This represents a significant gap in patient care.

Environmental patient-interfacing wastewater components including handwashing sinks, showers and toilets are sources of pathogens and antimicrobial resistant genes.  Kelly’s recently published work reports on the analysis of dissected drains and UBends removed from a medical ward which was about to undergo refurbishment, and where hospital acquired infections were endemic.  The pipe sections underwent molecular investigation to determine the microbial genetic makeup.  The authors found a high degree of similarity between the wastewater component recovered organisms and that of patients who had acquired an infection at > 48 hours post hospital admission.  In addition, many identical antibiotic resistant genes were shared between the groups.

In general, environmental surveillance for waterborne infections is poor, however the use of molecular techniques in routine clinical practice may help communicate the numbers of infections going under the radar.  Typically culture is used for bacterial identification, but this method is slow to achieve a result, has suboptimal sensitivity, and is not effective at detecting unusual pathogenic organisms.  Charalampous’s publication on respiratory metagenomics from intensive care units at Guy’s & St Thomas NHS Foundation Trust describes excellent use of this technology to improve clinical diagnosis, antibiotic stewardship and infection control.   Not only were results returned within a day, but they supported immediate decision making around correct antimicrobial prescribing.  Unexpected organisms were found in 21/128 samples taken from 87 patients, including a Legionella pneumophila which was subsequently isolated from the bed-side water outlet.  Routine application of respiratory metagenomics could increase visibility of waterborne pathogen burdens in our critical care settings, and adoption would be an advance in the standard of patient care. 

Donskey has recently published in the American Journal of Infection Control on potential interventions to reduce the risk of hospital-acquired infection from both floors and sinks.  There is a lack of practical solutions and validated measures to reduce the risk for dissemination of pathogens from these sites, and this paper highlights the need for practical approaches to address this universal problem.

Water flowing directly into the drain is still an uncomfortably common sight in our healthcare facilities, as is the level of visible splash from basins.  Modifications to the tap and increasing the size or depth of the basin can help alleviate some of these problems.  Ensuring no storage under or in the vicinity of the outlet is also critical. A slight weep from a UBend fixture could easily contaminate items stored underneath which are then transported direct to the patient.

Drains offer the perfect environment for biofilm formation (materials of construction, regular provision of nutrient carbon sources, ambient temperatures, stagnancy and intermittent use) and sharing of genetic material between microorganisms, including antibiotic resistance capability.  Splash and aerosol production lead to dispersal onto nearby surfaces, equipment, patients and clinical staff. 

Back draining basins, which are now commonplace in the UK, do offer some reduction compared with base draining basins, however as soon as there is slowing of flow or blockage these are equally effective at spreading contamination.  It is not suitable to use a bottle-brush scourer in the open aperture to disrupt biofilm as the scrubbing will release and flick biofilm in all directions.  However application of concentrated liquid disinfectant alone is not effective as the biofilm acts as a protective blanket, and exposure to disinfectants (or heat) without effective cleaning will lead to selection for tolerant bacteria.  There is some evidence that foam based disinfectants are more effective due to their improved distribution and contact time, however penetration of the biofilm remains limited and the selective pressure on local flora remains.  Regular intermittent application of foam disinfectants to the drain from the timepoint of component installation may have an improved management effect, however this has not been evidenced, validated nor longevity of effect verified.  Removal and replacement of the UBend and drain is often required where there is persistent Pseudomonas aeruginosa contamination at the outlet.

Drain covers, which allow fluids to pass unhindered yet prevent objects being washed into the aperture and restrict the release of disturbed aerosols from the drain and UBend, are appearing as an encouraging potential intervention for base draining sinks, basins and showers.  Understanding any impact on logistics for use, including response to slow flow/blockage, and verification of cleaning protocols needs to be part of any on-site implementation and verification. 

Removal of water sources from areas where there is insufficient use remains the gold standard as it eliminates the risk of infection to those in the vicinity. Insufficient use is not well defined, with many believing that outlets not used once per week are low use.  In reality, based on culture data supported by continual surveillance with remote monitoring, outlets need to be used multiple times per day in order to reduce colonisation and microbial amplification at the periphery. Therefore if the only use an outlet gets per day is the domestic cleaning staff or the flushing team, this is not enough, and the outlet should be reviewed for removal.

We hope these recently published papers are of interest to you and your teams.  If you have similar concerns regarding water services under your control, and would like to discuss the information shared in our Blog further and develop solutions for your facilities, please contact us


Donskey CJ. Update on potential interventions to reduce the risk for transmission of health care-associated pathogens from floors and sinks. Am J Infect Control. 2023 Nov;51(11S):A120-A125. doi: 10.1016/j.ajic.2023.03.009. PMID: 37890941.

Kelly SA, O’Connell NH, Thompson TP, Dillon L, Wu J, Creevey C, Kiely P, Slevin B, Powell J, Gilmore BF, Dunne CP. Large-scale characterization of hospital wastewater system microbiomes and clinical isolates from infected patients: profiling of multi-drug-resistant microbial species. J Hosp Infect. 2023 Nov;141:152-166. doi: 10.1016/j.jhin.2023.09.001. Epub 2023 Sep 9. PMID: 37696473.

Charalampous T, Aloclea-Medina A, Snell LB, Alder C, Tan M, Williams TGS, Al-Yaakoubi N, Humayun G, Meadows CIS, Wyncoll DLA, Paul R, Hemsley CJ, Jeyaratnam D, Newsholme W, Goldenberg S, Patel A, Tucker F, Nebbia G, Wilks M, Chand M, Cliff PR, Batra R, O’Grady J, Barrett NA, Edgeworth JD. Routine Metagenomics Service for Intensive Care Unit Patients with Respiratory Infection. Am J Respir Crit Care Med. 2023 Nov 8. doi: 10.1164/rccm.202305-0901OC. Epub ahead of print. PMID: 37938162.

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