Reducing anthrx contamination: use chlorine or soap and water, but not alcohol-based products. (EH Update).

Old-fashioned hand washing with soap and water significantly reduces the amount of contamination on volunteers' hands from a form of bacteria comparable to anthrax bacteria, according to a study that appeared in the March 12, 2003, issue of The Journal of the American Medical Association. A chlorine-based antiseptic product had about the same effectiveness and did not require running water. A waterless foam containing ethyl alcohol and used for disinfecting hands, however, was ineffective in removing spores of the bacteria.

The chief authors are Dr. David J. Weber and William A. Rutala, professors of medicine at the University of North Carolina School of Medicine.

Dr. Weber and co-authors chose to work with Bacillus atrophaeus, a bacterium harmless to humans but common in the environment and closely related to its deadly cousin, Bacillus anthracis. Studies done in the 1930s, 1940s, and 1950s with other agents found that Bacillus atrophaeus was slightly more resistant to germicides than anthrax. Researchers contaminated volunteers hands with the harmless microorganism and had them wash their hands for 10 seconds, 30 seconds, or 60 seconds with each product being tested. Using microbiological laboratory techniques, the scientists determined what happened when subjects washed with simple soap and water, the antiseptic agent chiorhexidine gluconate commonly used in hospitals, a waterless alcohol foam hospitals also employ and a new bleach-impregnated towel.

The data suggest that a soap-and-water wash is likely adequate for decontamination of exposed persons. Antimicrobial agents such as chlorhexidine gluconate did not improve elimination of B. atrophaeus spores compared with soap and water, and alcoholbased hand rubs should not be used because they are ineffective. When soap and running water are not available in the field, small amounts of water could be carried in rescue vehicles and added to the chlorine-containing towels for handwashing.

If anthrax contamination is a possibility workers should wear gloves but also wash their hands before and after glove removal, the authors recommend.

The study was supported by the North Carolina Statewide Program for Infection Control and Epidemiology and the University of North Carolina Heath Care System. The Chlorox Company and Advanced Sterilization Products contributed the bleach-impregnated towels.