Infection Control & Hospital Epidemiology (2018), 39, 1463–1466 doi:10.1017/ice.2018.273
Commentary
Water as a source for colonization and infection with multidrug- resistant pathogens: Focus on sinks
Sarah S. Lewis MD, MPH1,2, Becky A. Smith1,2, Emily E. Sickbert-Bennett3,4 and David J. Weber3,4 1Infection Prevention and Hospital Epidemiology, Duke University Hospital, Durham, North Carolina, 2Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, 3Department of Hospital Epidemiology, University of North Carolina Hospitals, Chapel Hill, North Carolina and 4Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
(Received 19 September 2018; accepted 30 September 2018)
Water distribution systems have long been known to be reservoirs and occasional sources for healthcare-associated infections (HAIs).1,2 Recently, hospital-building wastewater systems including sinks and drains have received more attention as potential sources of transmission of multidrug-resistant gram- negative bacilli.3–7 In this issue of Infection Control and Hospital Epidemiology, 2 studies by Dr Curtis Donskey’s research group add to our understanding of the importance of sink drains as reservoirs of pathogens and describe potential interventions to reduce contamination of surfaces surrounding sinks.8,9 This commentary focuses on the growing body of evidence linking sinks to HAIs and discusses strategies to mitigate the risk of transmission of pathogens from sinks to patients.
Sinks as Sources of Transmission of Multidrug-Resistant Organisms
A recent systematic review identified 32 reported outbreaks of carbapenem-resistant organisms (CRO) linked to hospital water supplies since the late 1990s, more than half of which were spe- cifically linked to drains or drainage systems and/or sinks.7 Likewise, Carling et al3 recently summarized 23 well- characterized outbreaks of CRO linked to wastewater drains. Common features of the reported outbreaks of CRO associated with wastewater drains include (1) long duration (mean, 37 months), (2) low attack rate (mean, 10.2 months between clinical cases), (3) high prevalence of sink colonization with the outbreak organism strain, and (4) difficult mitigation.3 By design, wastewater drains are rich environments for the amplification of microorganisms and the formation of biofilm. Drains consist of a strainer at the interface of the sink bowl and drain pipe, a P trap that contains water to prevent escape of sewer gases, and a tail pipe that connects the strainer to the P trap (Fig. 1). Limited ability to access to the tail pipe and the P trap for routine cleaning purposes makes biofilm removal and disinfection challenging, if not impossible.
Author for correspondence: Sarah S. Lewis, MD, MPH, DUMC 102359, Durham, NC 27710. E-mail:
Sarah.stamps@
duke.edu
Cite this article: Lewis SS, et al. (2018). Water as a source for colonization and
infection with multidrug-resistant pathogens: Focus on sinks. Infection Control & Hospital Epidemiology 2018, 39, 1463–1466. doi: 10.1017/ice.2018.273
© 2018 by The Society for Healthcare Epidemiology of America. All rights reserved. Use of Sinks in Hospitals
In most hospitals, sinks are located in direct patient-care areas (eg, patient rooms) and support areas (eg, corridors, medication preparation areas, soiled utility rooms), and they serve several purposes. First, sinks are used for hand washing by healthcare personnel, patients, and visitors. Hand hygiene is a key inter- vention to reduce transmission of pathogens in healthcare environments.11 Although healthcare personnel use waterless alcohol products more frequently than soap and water for hand hygiene, hand hygiene must be performed with soap and water when hands are visibly soiled and for pathogens that are not inactivated by alcohol such as nonenveloped viruses (eg, nor- ovirus) and spore-forming bacteria (eg, Clostridium difficile).12 Second, sinks may be used for the disposal of body fluids (eg, dialysate, urine, gastric residuals) or unused medications or tube feeds. Third, sinks are commonly used during perineal care (both routine care and after bowel movements) and for patient bathing. Finally, sinks may be used for soaking and initial cleaning of equipment that will undergo sterilization or high-level disinfection. Infection prevention principles dictate separation of clean and
dirty areas and tasks. For example, equipment reprocessing areas have separate designated sinks for dirty tasks such as initial equipment cleaning and clean tasks such as handwashing. Some
Pathogens may be transmitted from sink drains to patients
directly through contamination of healthcare-provider hands or indirectly through contamination of adjacent room surfaces and equipment. A recent in vitro study demonstrated that pathogens grow toward the sink strainer from contaminated P traps at a rate of ~2.5cm (1 inch) per day.10 Furthermore, contamination of the surrounding sink area with green fluorescent protein (GFP)- expressing Escherichia coli occurred only when the growth of the bacteria reached the sink drain but did not occur when the growth of the bacteria was limited to the P trap or tail pipe.10 At our institution, we documented transmission of KPC-producing Citrobacter freundii from a colonized in-room sink P trap and drain to the sink edge during routine use of the sink (Lewis and Smith, unpublished data). Factors including sink design, water flow rates8 and degree of drain colonization all influence the degree of pathogen transmission from sink drains.
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