The Personal Care Products Council and the American Cleaning Institute are touting a new study which they say confirms that consumer use of antimicrobial agents triclosan and triclocarbon does not lead to antibiotic or antibacterial resistance.

Published in the peer-reviewed International Journal of Microbiology Research, the study pitted OTC antibacterial liquid body cleansers and antibacterial bar soaps against non-antibacterial cleansers, measuring their impact on Staphylococcus bacteria from subjects’ forearms and susceptibility to10 antibiotics.

"There was no statistically significant difference in antibiotic resistance of Staphylococcus isolates obtained from the skin of regular antibacterial wash product users in comparison with non-antibacterial product users," says lead investigator Dr. Eugene Cole, professor of environmental health sciences in Brigham Young University's Department of Health Science.

There was also a “definitive” lack of antibiotic and antibacterial cross resistance among those bacteria, he notes.

Among the subjects who frequently use antibacterial wash products, there was no increase in antibiotic resistance of staph strains compared with individuals who do not use antibacterial wash products.

According to an Oct. 4 release from the Council and ACI, which funded the study, it “discounts claims that use of antibacterial wash products have contributed to the selection and spread of drug-resistant bacteria on human skin.”

Study Focuses On Staphylococcus Bacteria

The study examined subjects who fell into three categories – those who frequently use bath or shower products containing triclosan, those who frequently use bar soaps containing triclocarbon and those who do not use any antibacterial wash products.

Frequent users were defined as those who used triclosan- or triclocarbon-based products to wash their bodies on a regular basis during the 30 days prior to the study.

Study participants were selected randomly from a pool of 450 individuals – 70 for each of the three groups, for a total of 210 subjects.

Each subject was swabbed on both forearms for samples of Staphylococcus bacteria, which was then brought to a lab and tested against the 10 antibiotics often used to treat staph infections.

Staphylococcus was selected as the target bacteria indicator because of its “potential to develop antibiotic resistance and act as human pathogens,” according to the study.

Overall, among the subjects who frequently use antibacterial wash products containing triclosan/triclocarbon, there was no increase in antibiotic resistance of staph strains compared with the control group, consisting of those who do not use antibacterial wash products.

In testing coagulase-negative Staphylococcus from subjects for resistance to penicillin/methicillin, for example, data showed there was a statistically insignificant difference between triclosan product users and non-users. Among non-using participants, 17.9% showed methicillin resistance, while 23.5% of triclocarbon users and 20.4% of triclosan users showed resistance.

In comparison, methicillin resistance rates were 43.6% for outpatients in a 1998-1999 study conducted at 23 U.S. hospitals.

“There were no statistically significant differences across the drugs tested,” Cole, et al., say, with the exception of tetracycline, which showed resistance in the non-user group of 17%, comparatively higher than the combined triclosan/triclocarbon groups (9.7%).

Also in the study, the researchers found that bacteria from neither group showed increased resistance to triclosan or triclocarbon.

The study was conducted in part due to a call for research on the subject, as there has been “very limited evidence that there is a correlation between antibiotic and antibacterial agent resistance in community bacteria associated with humans,” Cole et al. write.

They also point out that the study protocol and its methods were reviewed and approved by an independent institutional review board.

Could Study Quell Triclosan Debate?

The study – titled “Investigation of Antibiotic and Antibacterial Susceptibility and Resistance in Staphylococcus from the Skin of Users and Non-Users of Antibacterial Wash Products in Home Environments” – comes during a contentious time for the ingredient.

While legislators and NGOs have called for triclosan to be banned due to concerns about antibiotic resistance and the ingredient’s suspected role in endocrine disruption, industry argues that evidence supporting such risks is lacking.

Reps. Louise M. Slaughter, D-N.Y., Betty McCollum, D-Minn., and Raul M. Grijalva, D-Ariz., asked for a triclosan ban in a November 2010 letter to FDA Commissioner Margaret Hamburg, and Rep. Ed Markey, D-Mass., also has encouraged FDA and EPA to outlaw the ingredient ( Also see "House Democrats Urge FDA To Ban Triclosan In Personal Care" - HBW Insight, 6 December, 2010. and Also see "Rep. Markey Calls For Triclosan Ban, Galvanized By Sympathetic FDA Letter" - HBW Insight, 12 April, 2010.).

The Environmental Working Group, Beyond Pesticides and Food & Water Watch also have come out against triclosan use in letters and petitions to federal agencies.

The Campaign for Safe Cosmetics has seen companies move away from including triclosan in products, but suggests the ingredient is still widely used (Also see "Campaign For Safe Cosmetics Looks To Maintain Momentum In 2011" - HBW Insight, 3 January, 2011.).

Industry maintains antibacterial products with triclosan are safe and effective.

Dr. Francis Kruszewski, ACI’s director of human health and safety, characterizes this latest study as an extension of the hygiene industry’s research efforts to ensure product and ingredient efficacy and safety.

“This is part of our industry's long-standing commitment to product stewardship," he says. “After decades of use, antibacterial wash products continue to play a beneficial role in everyday hygiene routines for millions of people around the world.”

The Council and ACI commissioned a survey earlier this year on consumer attitudes regarding antibacterial soap. Two-thirds of those surveyed said they would be “angry” if antibacterial soaps were taken off the market (“People Rely On Antibacterial Soap, Would Be "Angry" If It Weren't Available,” “The Rose Sheet” Jan. 24, 2011).

The groups recently launched FightGermsNow.com, a website for “fact-based, meaningful information on antibacterial soaps and ingredients” (Also see "In Brief" - HBW Insight, 9 May, 2011. In Brief).

The Cosmetic Ingredient Review Expert Panel reviewed triclosan in December 2010, determining the ingredient safe for use in cosmetics.

The panel limited its review to new data for triclosan in six areas – exposure, sourcing and dioxin impurities, photostability and dioxin photoproducts, carcinogenicity, endocrine disruption, and potential for bacterial resistance (“CIR Affirms Triclosan Safety, Opts For Formaldehyde Re-Review,” “The Rose Sheet” Dec. 20, 2010).

By Lauren Nardella

Triclosan Does Not Contribute To Antibacterial Resistance, New Study Says

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