Ordinary Soap Found as Effective as Antibacterial Soap

A new study has found that not only may antibacterial soap make antibiotics less effective, but that is no more useful than ordinary soap.

Researchers at the University of Michigan (U-M; Ann Arbor, USA) carried out a comprehensive analysis of 27 studies conducted between 1980 and 2006, and found that soaps containing triclosan within the range of concentrations commonly used in the community setting (0.1-0.45% wt/vol), was no more effective in preventing infectious illness than plain soap. Moreover, antibacterial soaps at formulations sold to the public do not remove any more bacteria from the hands during washing than plain soaps. Triclosan is used in higher concentrations in hospitals and other clinical settings, and may be more effective at reducing illness and bacteria at these locations.

Because of the way the main active ingredient in many antibacterial soaps (triclosan) reacts in the cells, it may cause some bacteria to become resistant to commonly used drugs such as amoxicillin, according to the researchers. These changes have not been detected at the population level, but Escherichia coli bacteria adapted in lab experiments showed resistance when exposed to as much as 0.1% wt/vol triclosan soap. The study was published in the August 2007 issue of the journal Clinical Infectious Diseases.

"What we are saying is that these E. coli could survive in the concentrations that we use in our [consumer formulated] antibacterial soaps,” said lead author Allison Aiello, Ph.D., M.Sc., an assistant professor of epidemiology at the U-M school of public health. "What it means for consumers is that we need to be aware of what's in the products. The soaps containing triclosan used in the community setting are no more effective than plain soap at preventing infectious illness symptoms, as well as reducing bacteria on the hands.”

Triclosan is a chlorinated aromatic compound that has functional groups representative of both ethers and phenols, and works mainly by inhibiting fatty acid synthesis. Because of the way triclosan kills the bacteria, mutations can happen at the targeted site.


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