Alcohol rubs surprisingly effective against C. diff
Alcohol rubs surprisingly effective against C. diff
Traditional hand washing still performs better
Contrary to conventional wisdom, alcohol hand rubs demonstrated surprising efficacy against Clostridium difficile (C. diff) in a study by one of the nation’s leading researchers on the troublesome nosocomial pathogen.1
"The alcohol rubs were actually more effective than we thought," says Dale Gerding, MD, associate chief of staff for research at the Hines VA Hospital and professor of medicine at Loyola University of Chicago.
Current infection control guidelines recommend alcohol-based hand gel hygiene rather than hand washing for the routine decontamination of hands that are not visibly soiled. Alcohol hand gels lack sporicidal activity but their effect on transmission of C. diff spores has not been determined. While the alcohol rubs reduced spore counts at higher levels than expected, residual C. diff spores still were readily transferred from subjects hands after use of the gels.
Traditional hand washing remains the most effective weapon against transmission of C. diff, but the findings give real world reassurance to the many ICPs who are heavily emphasizing alcohol hand rubs at their facilities. Poor compliance with hand washing was one of the primary reasons ICPs switched to the ease and convenience of alcohol rubs. However, a virulent new strain of C. diff is emerging as a nosocomial threat, bringing into question the new emphasis on alcohol for hand hygiene.
Gerding’s study was presented as a late-breaker recently in Washington, DC, at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. Three alcohol hand gels were compared to chlorhexidine gluconate hand washing for removal of C. diff spores from hands. Cultures were taken before and after hand decontamination. Transferability of C. diff after application of alcohol gel was tested by having half the volunteers inoculated with spores use an alcohol hand gel, and then shake hands with a noninoculated volunteer. Not surprisingly, alcohol gels were significantly less effective at removing C. diff spores from the hands of volunteers when compared to hand washing with chlorhexidine. However, there was a higher than expected reduction of spore counts following use of alcohol gels.
"You could do this with soap also and the results would be the same," Gerding explains. "Basically, washing with chlorhexidine is more effective. It reduced the number of spores a lot more than did the alcohol, but the alcohol preparations reduced spore counts around 95% to 97%. That is much more effective than what they thought they were going to be. But you add another log of effectiveness by washing hands with chlorhexidine."
In the study, a nontoxigenic strain of C. diff (5 x 105 colony-forming units [CFU] of spores) was seeded onto bare hands of 10 volunteers. Three alcohol hand gels were compared to chlorhexidine gluconate hand washing for removal of C. diff spores from hands. Palmar cultures were taken before and after hand decontamination using selective media containing taurocholate. Hand counts following inoculation were more than 3.2 Log10 CFU/cm2 and were estimated based on inoculum size and measured hand areas.
There was a greater reduction of spores (Log10CFU/cm2) after wash with chlorhexidine gluconate with any of the three alcohol hand gels. The alcohol hand gels were not statistically different when compared to each other, Gerding reports. A mean of 30% (range 10% to 55%) CFU/cm2 was transferred with hand shaking after use of alcohol gel.
"We had people use the alcohol and then shake hands with somebody — a third person — to see if what was left on the hands would be transferred to that person," Gerding tells Hospital Infection Control. "About 30% of the spores on the donor hands ended up on the recipient hands, so it does transfer after alcohol."
Reference
- Leischner J, Johnson S, Sambol S, et al. Effect of Alcohol Hand Gels and Chlorhexidine Hand Wash in Removing Spores of Clostridium difficile (CD) from Hands. Abstract LB-29. Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). Washington, DC; Dec. 16-19, 2005.