However, if you're a health-care worker you should go a step further and use alcohol-based towelettes, which are even more effective, the U.S. government said today in announcing a new set of hand-hygiene guidelines aimed at protecting patients.
Both the soap study and the hygiene guidelines will be presented tomorrow at the Infectious Diseases Society of America's annual meeting in Chicago.
"This is only one study, but it's a large study and as far as I know nothing at this point has looked at the soaps head-to-head," says Dr. Julia Garcia-Diaz, an infectious diseases specialist at the Ochsner Clinic Foundation in New Orleans. "The results are a little surprising because you would expect the antibacterial soap to have a fewer number of colonies, and this was not the case. They both rate about the same."
The study was the first double-blind, randomized controlled clinical trial to compare the two types of soaps. About half to two-thirds of hand cleansers are now labeled as antibacterial.
The researchers followed those in more than 200 New York City households over the course of a year. Half were randomly assigned to use antibacterial soap and the other half used regular soap. Cultures were taken after just one hand-washing and again after a year. Neither the participants nor the investigators analyzing the cultures knew who had been assigned to which group.
At the end of the year, all study participants, regardless of which type of soap they had been using, had significant reductions in the number of microbes on their hands.
"Participants had an average of about 1 million bacteria on their hands at the beginning of the study and 10,000 to 100,000 at the end of the study," study author Elaine Larson says. "That's all within the realm of normal."
"Everybody at the end of the year had cleaner hands," says Larson, an associate dean for research for Columbia University School of Nursing in New York City. "The bacterial counts went down on everybody, whether or not they used antibacterial or plain soap -- which to me says that hand-washing works, hand-washing with any soap works."
The study did not address the issue of whether antibacterial soap contributes to bacterial resistance (though the amounts were probably too small to matter). Nor did it deal with whether or not the antibacterial soaps actually prevented infections. "We just looked at reduced bacterial count on the hands," Larson says.
As the soap industry points out, the study does not look at transient or acquired bacteria. "The primary role of antibacterial hand soaps is to kill the transient bacteria that are acquired and which may be transferred following such tasks as preparing food, changing diapers, caring for a sick person and not to affect or eliminate normal skin bacteria," reads a statement prepared by the Soap and Detergent Association and the Cosmetic, Toiletry, and Fragrance Association.
So which should it be -- antibacterial or regular?
For killing germs, Larson recommends using waterless, alcohol-based towelettes such as those found in hospitals. "These don't require a sink and they are excellent antiseptics," she says. "This is what I would recommend to the public if they want to kill bacteria. It works at least as fast if not better than antibacterial soap."
That's exactly what the U.S. Centers for Disease Control and Prevention (CDC) is urging health-care workers to do.
"Hand hygiene saves lives," says CDC director Dr. Julie Gerberding. The agency isn't recommending that hospitals abandon soap and water. However, it believes that the alcohol solutions improve adherence to hand-washing guidelines with their convenience and are better at killing germs. Although these products cost more up front, they may save money in the long run by being more effective and easier to use than soap and water.
The CDC estimates that some 2 million patients in the U.S. get an infection in hospitals, and about 90,000 of these patients die.
A study in Geneva, Switzerland, showed that use of the alcohol sanitizers led to fewer cases of drug-resistant staph infections and a reduction in overall hospital-acquired infections.
Gerberding says the policy does not apply to the home, where soap and water can do the job well.
And remember that bacteria are not all bad. "If you are a perfectly healthy person, the bacteria will live happily with you," Garcia-Diaz says. "If you're an HIV patient it may not be so good. It depends on the host and what is going on with that particular patient."
If you are healthy, regular soap is still the way to go for daily hygiene. Just be sure to wash all the surfaces of your hands including between your fingers.
What To Do
For more on hand-washing, visit the U.S. Centers for Disease Control and Prevention. To learn about antibiotic resistance, go to the National Antimicrobial Resistance Monitoring System.