Some antibacterial soaps are no better at preventing infections than regular soap, and may cause bacteria to become resistant to certain types of antibiotics, a new U.S. study indicates.

In their analysis of triclosan, the main active ingredient in antibacterial soaps as well as some detergents, deodorants, cosmetics and lotions, researchers at the University of Michigan School of Public Health found the chemical did not remove any more bacteria from the hands during washing than the ingredients used in plain soaps.

"What it means for consumers is that we need to be aware of what's in the products," researcher Allison Aiello said. "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."

In fact, because of the way triclosan reacts in the cells, it may actually cause some bacteria to become resistant to commonly used drugs such as amoxicillin, the study suggests..

The study, "Consumer Antibacterial Soaps: Effective or Just Risky," is in the August edition of Clinical Infectious Diseases.

The researchers examined 27 studies conducted between 1980 and 2006, but did not analyze other antiseptic products such as alcohol or bleach-based sanitizers.

It recommends that U.S. government regulators evaluate antibacterial product claims and advertising.

The Food and Drug Administration does not formally regulate the levels of triclosan in consumer products.

Health Canada recommends people avoid using antibacterial products such as those containing triclosan because they kill good bacteria that fight bad germs, and because of concerns over antibacterial resistance. It has included triclosan on its list of prohibited and restricted cosmetic ingredients.

The Michigan researchers found triclosan can be more effective at reducing illness and bacteria when used in higher concentrations in hospitals and other clinical settings.

However, amounts found in consumer products like hand soap do little to combat bacteria bugs, their study indicates.