By Ethan Covey

Hydrogen peroxide foam is an affordable, effective method of disinfecting hospital sinks, according to a new study.

The solution was found to be more effective than bleach in reducing total number of gram-negative colony-forming units (CFU) in sink drains (Infect Control Hosp Epidemiol [Epub Apr 17, 2019]. doi.org/ 10.1017/ ice.2019.72usuqaexaadvbttvfcrswveesczsxwfux).

“Sink drains appear to be reservoirs for antibiotic-resistant organisms,” said Silvia Munoz-Price, MD, PhD, a professor of medicine in the Department of Medicine, Division of Infectious Diseases, at Froedtert and the Medical College of Wisconsin, in Milwaukee. “At our institution, we recently dealt with an outbreak of KPC [Klebsiella pneumoniae carbapenemase]–producing Enterobacteriaceae. During the investigation, we evaluated the sink drains in one of our intensive care units and found that more than 50% of the sinks were positive for the KPC gene, although by culture methods we had a much lower yield.”

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Although studies have shown that thermal p-trap disinfection technology is useful in decreasing the acquisition of carbapenemase-producing organisms, the cost of the necessary devices is high.

To find an effective, affordable way to disinfect the drains, Dr. Munoz-Price and her colleagues studied the use of bleach (1:10 dilution of a 6% sodium hypochlorite disinfectant) and a commercially available foaming hydrogen peroxide formulation diluted at 6 ounces per gallon of water according to label instructions and applied through a pump-up foaming applicator.

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Patient rooms in the 26-bed medical ICU were assigned to one of three groups: hydrogen peroxide foam, bleach or control. For sinks in the hydrogen peroxide group, the foam was applied to the inside of each drain for three minutes. In the bleach group, 32 ounces of the 1:10 solution were poured through the drain.

On day 1, a statistically significant reduction in bacterial CFU was observed in the group treated with hydrogen peroxide, compared with the patient rooms treated with bleach (P=0.0077) and the control group (P<0.0001).

“[That the foam was more effective than bleach] was not surprising given that once poured, the bleach is probably in contact with the sink drains for a very limited time,” Dr. Munoz-Price said. “Additionally, bleach is corrosive, which is not ideal if we were to implement a regular disinfection of these drains.”

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By day 7, bacterial CFU counts had reverted to pretreatment levels in all sinks. A forthcoming study conducted by the same team of researchers explores how much time the disinfecting effect of the foam lasts.