Treating ICU Sink Drains With Acetic Acid Eradicated a CPE Outbreak
Key Takeaway
Carbapenemase-producing Enterobacteriaceae colonized almost every sink in a single intensive care unit. Rather than accept the drains as a permanent reservoir, the team decontaminated them with acetic acid three times a week. Both sink colonization and patient CPE cases fell until the epidemic was considered eradicated, confirming the sink drains were driving transmission.
The Study
Smolders and colleagues investigated a carbapenemase-producing Enterobacteriaceae (CPE) outbreak in a single intensive care unit in Belgium (Ziekenhuis Netwerk Antwerpen). The outbreak strains predominantly carried the OXA-48 carbapenemase, and CPE was isolated from almost all sinks in the ICU patient rooms, implicating the sink drains as the environmental reservoir.
The team decontaminated the colonized drains with 250 mL of 25% acetic acid three times a week and followed sink colonization for six months. In vitro, the growth of every isolate was inhibited at an acetic-acid concentration at or below the one used. A statistically significant relationship was demonstrated between contaminated sinks and CPE patient acquisition, and as drain colonization fell, patient CPE cases fell with it until the epidemic was considered eradicated.
Key Findings
Nearly every ICU sink was colonized
Carbapenemase-producing Enterobacteriaceae, predominantly carrying the OXA-48 gene, were isolated from almost all sinks in the ICU patient rooms, identifying the sink drains as the environmental reservoir.
Contaminated sinks were statistically linked to patient CPE
A positive and statistically significant relationship was demonstrated between contaminated sinks and CPE acquisition by patients, connecting the drain reservoir to clinical infections.
Acetic acid decontaminated the drains
Treating the drains with 250 mL of 25% acetic acid three times a week reduced colonization; in vitro, all isolates were inhibited at an acetic-acid concentration at or below the one used.
The epidemic was eradicated
As sink-drain colonization fell, both colonized sinks and patient CPE cases decreased drastically, and the outbreak was considered eradicated, showing that acting on the drain controlled the infections.
What This Means for Your Facility
This study is a clear demonstration that sink drains can be the reservoir sustaining a resistant-organism outbreak, and that acting on the drain, not just the patients, is what brings it under control. The same standing-water trap environment exists in the floor drains found throughout commercial, food-service, and healthcare facilities.
Smolders controlled this outbreak with a repeated chemical protocol, dosing every colonized sink three times a week and monitoring for months. That works, but it depends on ongoing labor and consistent compliance. A waterless trap seal removes the standing water a conventional trap relies on, the environment in which drain biofilm establishes; it does not remediate an existing biofilm.
Green Drain does not manage outbreaks and this study did not test a trap seal. But its central finding, that the sink drain is the reservoir that has to be addressed, is why a waterless trap seal belongs in a preventive maintenance program alongside cleaning and infection-prevention measures. Independent SGS testing (Report QDF25-0049810-01) found the GD3 retained over 99.9% of an aerosolized viral surrogate (MS2 bacteriophage) in a controlled bench test.
Full Citation
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A Preventive Approach to Standing Water in Drains
Green Drain's waterless trap seals remove the standing water a conventional trap relies on; they do not remediate an existing biofilm. A passive seal that holds without repeated dosing.
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