Antibacterial soap more harmful than helpful

Antibacterial soaps show no hygiene benefits over plain soaps and, instead, may increase bacterial resistance to some common antibiotics, according to a study in the August edition of Clinical Infectious Diseases.

In a comprehensive analysis of whether antibacterial soaps work better than plain soaps, a team of scientists in the US, led by Allison Aiello of the University of Michigan School of Public Health, found that washing hands with an antibacterial soap was no more effective in preventing infectious illness than plain soap.

The study, Consumer Antibacterial Soaps: Effective or Just Risky?, looked at 27 studies conducted between 1980 and 2006 and found that soaps containing triclosan within the concentration range commonly used in the community (0.1 to 0.45 % wt/vol) were no more effective than plain soaps.

Because of the way the main active ingredient "” triclosa "” in many antibacterial soaps reacts in the cells, it may cause some bacteria to become resistant to commonly used drugs such as amoxicillin, the researchers say.

These changes have not been detected at the population level, but E. coli bacteria bugs adapted in lab experiments showed resistance when exposed to as much as 0.1 % wt/vol triclosan soap.

"What we are saying is that these E. coli could survive in the concentrations that we use in our antibacterial soaps," Aiello said.

"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 works by targeting a biochemical pathway in the bacteria that allows the bacteria to keep its cell wall intact.

However, mutations can happen at the targeted site, providing the bacteria with a resistance to the now inhibited triclosan.

The analysis calls for government regulators to evaluate antibacterial product claims and advertising.