Tackling Dirty Sinks

For decades we’ve been taught that hand hygiene is the most critical aspect of infection control. Although that may be true, what about the sinks and faucets? These oft overlooked areas can easily pose infection control risks. How clean can your hands really be if the sink and faucet are heavily contaminated and dirty? The topic of slime and biofilm is increasingly being brought up as we focus more on vulnerabilities in health care and the role of environmental contamination.

Earlier this year, there were studies that identified sink proximity to toilets as a risk factor for contamination. Bugs like Klebsiella pneumoniae carbapenemase-producing organisms tend to be prolific in moist environments and are often pervasive in intensive care unit sinks and drains. Researchers found that sinks near toilets were 4-times more likely to host the organisms than those further from toilets.

More and more, infection prevention is having to look at hospital faucets and sinks for their role in hosting microbial growth. This was also a topic of interest at last week’s annual conference of the Association for Professionals in Infection Control and Epidemiology (APIC 2019). Investigators with the University of Michigan Health System discussed how they worked to identify vulnerabilities and potential sink designs that might contribute to bioburden and biofilm in hospital faucets. Assessing 8 different designs across 4 intensive care units, the research team ultimately found that those sinks with a more shallow depth tended to allow higher rates of contamination (ie, splash of dirty water) onto equipment, surfaces, and patient care areas. In some instances, the splash of contaminated water could be found up to 4 feet from the sink.

“The inside of faucets where you can’t clean were much dirtier than expected,” said study author Kristen VanderElzen, MPH, CIC. “Potentially hazardous germs in and around sinks present a quandary for infection preventionists, since having accessible sinks for hand washing is so integral to everything we promote. Acting on the information we found, we have undertaken a comprehensive faucet replacement program across our hospital.”

Utilizing adenosine triphosphate (ATP) testing for cleanliness, investigators found that the visible biofilm had higher ATP readings and, when cultured, grew Pseudomonas aeruginosa, mold, and other environmentally-common microorganisms. One of the other issues the research team found was aerators on sinks that had previously been moved, meaning that there wasn’t a process for maintaining consistency in facilities and construction. Aerators are associated with an increase in risk, as they have been found to be reservoirs for drug-resistant bacteria.

In the face of these findings, the team opted to improve infection control measures around the sinks through sink guards, which help reduce splash.

The truth is that we are continuously finding new vulnerabilities in health care settings and ways for microbes to contaminate surfaces, objects, and patients. Infection control is constantly evolving and it’s important to broaden the scope of what we consider as sources for transmission. We all know sinks are dirty, but that hasn’t translated into really assessing how the sink design might be contributing to the spread of infections. These findings and the growing body of literature surrounding sink-sourced contamination shed light on an issue we have been ignoring for a while.