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Oct. 24, 2005


Antibacterial soaps no better at cleaning your hands

ANN ARBOR, Mich.—Germophobic Americans have antibacterial soaps in their bathrooms and kitchens, they carry hand sanitizing gels and wipes when they're away from home, and their grocery stores have even gotten into the act, offering wipes for the cart handles.

But Allison Aiello, assistant professor of epidemiology at the University of Michigan School of Public Health, is worried we might inadvertently develop superbugs, bacteria resistant to the arsenal of cleansers and soaps.

The concern, she explained, is that the ingredient triclosan, which most consumer antibacterial liquid soaps contain, changes the ecological balance on your hands by killing off some—but not all—of the bacteria there. In addition, laboratory tests have shown that use of antibacterials can lead to cross-resistance with oral antibiotics that are used to treat some infections.

Aiello appeared before the Food and Drug Administration's Non-prescription Drugs Advisory Committee Thursday to discuss the health benefits and risks of antibacterial soaps.

She told the committee that any kind of soap, with or without antibacterial ingredients, can help remove bugs from the hands. Soap helps to loosen dirt, so that water can rinse it down the drain. She feels it is unnecessary to use antibacterial soaps since research shows that those products are not any more effective than plain soap against common infections found in the household setting.

Aiello, who is part of Public Health's Center for Social Epidemiology and Population Health, also has an article on the topic in October's issue of the journal Emerging Infectious Diseases, published by the Centers for Disease Control and Prevention. It is the first randomized study in the United States to examine antibacterial use in the home setting to look for increased antibiotic resistance.

In that article, Aiello studied about 200 households and found that use of hand soap containing the antibacterial agent triclosan was not associated with increased antibiotic resistance a year later.

However, Aiello said further study is needed. She notes that one year is probably not long enough to see a change in antibiotic resistance at the population level, so she plans to begin long-term surveillance of bacteria in the community setting for changes in levels of resistance to triclosan.

Coauthors on the October article are Bonnie Marshall and Stuart Levy of Tufts University and Phyllis Della-Latta, Susan Lin and Elaine Larson of Columbia University.

Aiello began studying hygiene products as a graduate student. She looked at six decades of hygiene-related advertising, going back to 1940 in women's magazines like Good Housekeeping and Family Circle to track social changes in our cleaning habits.

In a 2002 article in the Lancet, she reviewed numerous studies and concluded that personal and environmental hygiene is an effective way to reduce the spread of infections in the community setting even in "an era of unprecedented cleanliness and improved public health infrastructure."

"There is a continued, measurable, positive effect of personal and environmental hygiene," she and coauthor Elaine Larson wrote.

Alcohol-based hand sanitizers work differently than antibacterial soaps, Aiello added. After removing visible dirt from the hands using soap and water, alcohol can effectively wipe out most pathogenic bacteria and viruses without leaving a residue behind, which is part of why the CDC recommends the use of alcohol-based hand rubs by health care personnel when seeing patients.

Aiello said she hopes the FDA will continue to monitor potential risks associated with antibacterial soaps, and possibly regulate their use as an over-the-counter medication.

Aiello received support for her research from the Robert Wood Johnson Health & Society Scholars Program.

Aiello's faculty profile

October issue of Emerging Infectious Diseases

Aiello's article

FDA Nonprescription Drugs Advisory Committee

CDC hand hygiene guidelines


Contact: Colleen Newvine
Phone: (734) 647-4411