environmental hygiene
environmental hygiene
By Richard Dixon and David Koenig , PhD
Healthcare Sinks as a Source of Pathogens and a Potential Solution
Authors ’ note
The purpose of this article is to stimulate a discussion on an innovative concept to clean and disinfect healthcare sink drains , which are a common source of pathogens .
It is not intended to claim any outcomes .
Antimicrobial resistance ( AMR ) is among the World Health Organization ( WHO )’ s top 10 threats for global health . The rise of AMR was initially driven by the misuse of antimicrobials in livestock , crops , and humans . The rise in AMR microbes has reduced or eliminated the effectiveness of many antibiotics used to treat infections such there are limited alternatives . Lack of treatment is predicted to lead to a tenfold increase in AMR associated deaths by 2050 . AMR microbes and associated health impacts are expected to become burden on the global economy leading to a rise in poverty .
Prevention is at the core for stopping AMR emergence . It is well known that the environment plays a key role in the development and transmission of AMR microbes . Conversely , the environment is a key area for active prevention of AMR . In the hospitals , the sink has been shown to contribute to the rise of AMR . Not only is the sink a source of hospital-acquired infections ( HAIs ) but is also a source for dispersal of AMR microbes into the community . Therefore , eliminating the sink as a source of HAIs and AMR microbes will greatly help in the quest for controlling AMR globally .
Sinks and Drains
Researchers all over the world have been investigating sinks and drains as a source of HAI microorganisms , especially carbapenem-resistant Enterobacteriaceae ( CRE ). CRE infections are of particular concern because of their ability to transfer their AMR genetic elements from one bacterial species to another , for example from carbapenem-resistant Klebsiella pneumoniae to Escherichia coli . In 2000 , a paper in Current Opinions in Microbiology posed the question , “ Is the emergence of carbapenemase a problem waiting to happen ?” Almost 20 years on , the problem is here .
Reports that suspected sinks and drains could be the source of CRE that caused HAIs began to emerge in 2003 . In a 2017 review , The Hospital Water Environment as a Reservoir for CRE Causing Hospital-Acquired Infections , 17 studies identified sinks as a potential source of microorganisms causing HAI outbreaks , often in the Intensive Care Unit ( ICU ). Additionally , AMR microbes can colonize sinks and associated plumbing allowing for the transmission of AMR genes to non-AMR microbes , increasing the AMR problem exponentially . In that the waste stream from a sink ultimately reaches the municipal wastewater facilities , AMR microbes and other pathogens can be released into the community .
Figure 1 : Carbapenem-Resistant Enterobacteriaceae ( CRE ). Courtesy of NIAID
Sink design directly drives the environmental conditions that favor microbial growth on plumbing line surfaces and ultimately favor AMR development . To prevent sewer gases being released into the room , sinks use water traps . These traps were first invented by Alexander Cumming in 1775 , the S-bend trap . Eventually , P-trap ( Figure 2 ) design was adopted that added a 90-degree fitting on the outlet side of a U-bend . The P-trap was popularized by Thomas Crapper in the 1880s and remains in use today . By design the P-trap allows for the sink lines to remain wet , but as was probably underappreciated in 1880 these conditions allow for the rapid growth of biofilms that will harbor pathogens and AMR microbes .
AMR microbes can spread along waste lines connecting sinks and colonize the P-trap . Once there , they form a biofilm which can grow upwards to reach the sink strainer at a rate of up to 2.5 cm a day . When the water from the faucet hits the sink strainer there is splashing that carries pathogens ( HAI ) and AMR microbes in droplets onto surrounding counters and the floor up to 1 meter away . Patient-care and
Figure 2 : The P-trap of a sink . Courtesy of Adobe Stock
30 september 2023 • www . healthcarehygienemagazine . com