Too Clean for Comfort.

A research survey of liquid and solid soaps from across the country reveals that 45% contained antibacterial agents--chemicals that scientists say may not benefit human health but might instead create stronger bugs. In a presentation at the annual meeting of the Infectious Diseases Society of America in September 2000, Eli N. Perencevich, a research fellow in infectious diseases at Beth Israel Deaconess Medical Center in Boston, and colleagues described how they went through the lists of liquid and solid soaps sold in 23 national and local stores to see how many of them contained antibacterial agents.

Perencevich and colleagues examined 395 national brand liquid soaps and 733 bar soaps on display at stores in 10 states across the country. They found that 76% of the liquid soaps contained triclosan and about 30% of the bar soaps contained triclocarban. "Recent research into the action of triclosan has raised the concern that these products may encourage resistance to triclosan and other microbial agents," Perencevich says. "With so many of these products on the market, consumers may not realize they are purchasing soaps that contain antimicrobials. Perhaps people should check the products' ingredients closely when they make their next soap purchase."

"Although triclosan has been used as an antimicrobial for many years, it's only recently that we have learned how it acts on bacteria," says Stuart Levy, a professor of molecular biology at the Tufts University School of Medicine in Boston and president of the Boston-based Alliance for the Prudent Use of Antibiotics. "There is a specific gene in Escherichia coli and many other bacteria that produces an enzyme to make the cell wall. Triclosan disrupts the enzyme so that the bacteria can't make the cell wall, and therefore, cannot replicate." According to Levy, if there is a mutation in this gene, it may lead to bacteria that are resistant to triclosan or other antibiotic agents. "Triclosan doesn't cause a mutation," he says, "but by killing normal bacteria it creates an environment where the resistant, mutated bacteria are more likely to survive."

"No one has ever been able to prove that using antibacterial soaps meant that anyone was better off than those using standard soap," says Perencevich. "There has been no scientific data published to support the claim that adding these compounds to household products prevents infection. However, there are studies that suggest use of such products kills off the sensitive bacteria, leaving hardier bacteria such as E. coli and Staphylococcus aureus, which could be detrimental to health." Perencevich adds, "The fear is that use of these products will result in bacteria that live longer."

That fear may be misplaced, contend industry representatives. "The rising incidence of antibiotic drug-resistant bacteria is a serious worldwide concern," says Jerry McEwen, vice president for science at the Cosmetic, Toiletry, and Fragrance Association, based in Washington, D.C. "There is no real-life evidence that antibacterial products--as they are normally used in hospitals, in food preparation, and in people's homes--contribute to bacterial resistance." He continues, "While some studies have shown that antibacterial ingredients may promote resistant bacteria, these studies have been done under controlled laboratory conditions that do not reflect what happens to bacteria that consumers encounter in the real world."

Nevertheless, says Perencevich, "The magnitude of the availability of antibacterial soap products that we documented in our survey is cause for concern. This study suggests that further surveillance and study of triclosan resistance is warranted."