Alcohol Rub, Antiseptic Wipes Inferior at Removing Clostridium difficile

Bob Roehr

September 21, 2007

September 21, 2007 (Chicago) — Old-fashioned soap and water are better than antiseptic wipes and alcohol rubs in removing Clostridium difficile, according to a study by McGill University researcher Matthew Oughton, MD, presented here at the 47th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

Dr. Oughton brewed up a nontoxigenic strain of C difficile to create a standard batch (C difficile colony count 5.15 log10 colony forming units [CFU]/mL, with 62% spores) of pathogen and used it throughout the 2 studies. One study used a latex glove with C difficile–laced "glove juice," the other a hard tile surface, to first measure transfer of the pathogen to hands and then the efficacy of the 6 interventions at reducing it.

In the glove study, the no-handwashing group found 3.8 log 10 CFU/mL surviving the procedure; warm water and plain soap left 2.0 log 10 CFU/mL; cold water and plain soap. 2.0 log 10 CFU/mL; warm water and antibacterial soap, 2.4 log 10 CFU/mL; antiseptic hand wipes. 3.2 log 10 CFU/mL; and alcohol hand rub, 3.8 log 10 CFU/mL.

The surface contamination study found an even greater differential in outcomes between the groups, using a measure of C difficile colony count per plate, yielding 48.8, 0.4, 0.4, 0.3, 8.0, and 37.7 units for no handwashing, warm water and plain soap, cold water and plain soap, warm water and antibacterial soap, antiseptic hand wipes, and alcohol hand rub, respectively. Dr. Oughton stated, "All of the interventions except for the alcohol hand rub decreased the colony counts by a large number."

He concluded, "Plain soapy water was superior to antiseptic hand wipes and alcohol hands rubs." He suggested that the small effect for antiseptic hand wipes seen in the surface contamination study might come from "moving the C difficile from the touching surfaces of your hand to nontouching surfaces, which may be better than not washing at all."

Dr. Oughton told Medscape the spores are what make C difficile so hard to eliminate. To recover the pathogen from a sample, "you can use alcohol to kill off everything else, but the chemical action doesn't touch the spores." The solution is physical removal.

 

John M. Boyce, MD, chief of the infectious disease section at the Hospital of Saint Raphael in New Haven, Connecticut, explained that reduction of C difficile on contaminated hands comes from the friction involved with rinsing and drying that occurs during handwashing — it is not a result of an antiseptic agent. "Therefore, it comes as no surprise if alcohol hand rubs, which do not require rinsing or mechanical drying, are shown to be less effective than handwashing" in reducing levels of the pathogen.

Dr. Boyce noted that a previous study had found alcohol hand rubs to have greater activity against C difficile than Dr. Oughton reported. He is awaiting peer review publication and further study for a more definitive resolution of the issue, he said.

Could the increased use of alcohol hand rubs, if at the expense of less handwashing, help to explain the increased outbreaks of C difficile in hospital settings? Dr. Boyce does not think so. A study at his own hospital, published in 2006, "showed that the incidence of C difficile cases did not increase over a period of 3 years, despite a 10-fold increase in the use of alcohol-based hand rubs in our facility." Other studies have found similar results.

In July 2005 the Centers for Disease Control and Prevention recommended "using only soap and water for hand hygiene when caring for patients with C. difficile–associated disease; alcohol-based hand rubs may not be as effective against spore-forming bacteria."

Dr. Oughton and Dr. Boyce report no relevant financial relationships.

47th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy: Abstract K-1376a. Presented September 19, 2007.

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