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Soap and Water Washing Beats Alcohol Rubs, Antiseptic Wipes for Removing C. Difficile: Presented at ICAAC

By John Gever

CHICAGO, IL -- September 20, 2007 -- Nothing beats old-fashioned soap and water washing for removing Clostridium difficile from hands, according to research presented here at the 47th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

In many healthcare facilities, soap and water for hand cleaning has given way to alcohol-based rubs and packaged antiseptic wipes. However, their effectiveness is uncertain when it comes to spore-forming microbes such as C. difficile, according to Matthew Oughton, MD, FRCPC, Postdoctoral Fellow, Department of Medicine, McGill University, Montreal, Quebec, Canada.

Dr. Oughton and colleagues conducted a study to compare the effectiveness in removing C. difficile of three soap-based hand-washing regimens, antiseptic hand wipes, and alcohol-based hand rubs, as well as no washing. The three soap-based methods were cold water and plain soap, warm water and plain soap, and warm water and antiseptic soap.

Ten volunteers participated in the trial, with each subject undergoing every hand-cleaning regimen on separate occasions. Each regimen was tested with two different contamination models. In one -- called the glove juice model -- subjects' hands were exposed to a C. difficile broth; they then used one of the cleaning methods (or no wash) and put their hands into gloves containing a sterile broth which was sampled and tested for C. difficile colonies. In the other contamination model --the surface contamination model -- the C. difficile broth was put on a surface and then dried; subjects touched the surface, applied one of the cleaning methods, and had their hands sampled directly for C. difficile.

Results show that the alcohol-based hand rub was completely ineffective in the glove-juice model, Dr. Oughton said. C. difficile colony counts were the same with the alcohol rub as with no washing. All the other cleaning methods significantly reduced C. difficile colony counts relative to no washing (P <.05). Moreover, the two regimens involving plain soap were significantly superior to both the alcohol rub and to the antiseptic wipes (P <.05).

In the surface contamination model, the alcohol rub again failed to show significant effectiveness compared with no washing. The other cleaning methods, including the antiseptic wipes, all reduced C. difficile colony counts to near zero, with no significant differences between them.

Dr. Oughton noted that the hand-cleaning regimens used in the study all were less intensive than the standard recommendations for each. For example, the soap-and-water washes lasted 10 seconds, rather than the 30 seconds most often recommended. He said the intent was to most closely match actual practice in healthcare facilities, which usually falls short of recommendations.

He also said it is possible that the rubs and wipes may dislodge spores from so-called touch surfaces on the hands, such as fingertips and palms, and therefore be better than not washing.


[Presentation title: Alcohol Rub and Antiseptic Wipes Are Inferior to Soap and Water for Removal of Clostridium Difficile by Handwashing. Abstract K-1376a]

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