Consumers should ensure products have sufficient concentration of active ingredient
Consumers should continue to use antibacterial cleaning products with sufficient active ingredient to kill germs, confident they contribute to healthy living environments, according to a study by a Brigham Young University researcher that verifies such products aren't contributing to antibiotic resistance in household bacteria.
Eugene C. Cole, BYU professor of health science and lead author of the study in Wednesday's (Sept. 24) "Journal of Applied Microbiology," says some consumers may be making purchase decisions thinking these products are a major contributor to antibiotic resistance, which occurs when organisms like E. coli and Staphylococcus aureus adapt until they are unaffected by medical treatment with antibiotics.
"Antibiotic resistance continues to be a worldwide health concern," said Cole. "But our study indicates that there isn't a relationship between this problem and antibacterial cleaning products used in the home."
With this knowledge, research efforts can now be focused on the main causes of antibacterial resistance, such as over-prescribing of antibiotics by physicians, the use of antibiotics to promote livestock growth and misuse by the general public.
"Often, patients fail to take a full course of medication. Or they use old, outdated prescriptions or take antibiotics when they really have a viral infection, which isn't affected by these kinds of drugs," said Cole. "So, instead of killing off harmful, disease-causing agents, people are knocking off the weaker ones and selecting for those that are resistant to treatment."
Reckitt Benckiser, a leading manufacturer of cleaning products, sponsored Cole to design and direct the study.
"Although industry sponsored the study, it was a truly independent, scientific effort," said Cole, noting the study's acceptance in the journal by independent peer review.
Kurt Stevenson is an adjunct professor in the Division of Clinical Epidemiology of the Department of Medicine at the University of Utah School of Medicine.
"Antibiotic resistance has become increasingly common and is evolving into a major public health concern. Inappropriate use of antibiotics has clearly been associated with this rise, causing some scientists to speculate that the widespread home use of disinfectants and antibacterial-containing antiseptics may also contribute to the problem," said Stevenson, who is also an infectious diseases physician and epidemiologist studying the spread of antibiotic resistance in rural communities for Qualis Health, a nonprofit health care quality improvement organization. "This well-conceived and well-designed study by Cole and associates indicates there is no link between home use of these products and the presence of antibiotic-resistant bacteria in the home environment. This reduces the concern raised by scientists about the everyday home use of these products."
As part of the two-year study, researchers took samples from a variety of kitchen and bathroom surfaces, as well as from the hands and mouths of 60 participating families in the United States and the United Kingdom who were verified as either users or non-users of antibacterial household and personal hygiene products. From thousands of isolates of potentially disease-causing bacteria, more than 1,200 were tested for resistance to commonly used antibiotics. From those, representative antibiotic-resistant and -susceptible bacteria were tested against four common antibacterial ingredients used in household cleaning and personal hygiene products -- triclosan, PCMX, pine oil and quaternary ammonium compound.
"Nothing stood out to indicate that the use of these antibacterial products was contributing to increased antibiotic resistance," said Cole.
However, researchers did find an increased prevalence of potential disease-causing organisms in the homes of the non-users. Does that mean that because individuals did not use these products in their homes that harmful bacteria were thriving?
"We can't really say that, since perhaps users buy and clean with these products because they are more concerned with controlling potentially infectious bacteria and are more aggressive in that way than the non-user," said Cole, who insists regular cleaning is important for everyone because the home environment is also a health care environment.
"When people are sick with diarrhea, respiratory infections or sustain a wound, they don't go to a hospital," said Cole. "They may go to a doctor, who may or may not prescribe something, but they stay home to convalesce."
Other areas of concern include day care centers, where workers who change diapers should regularly wash hands and use hand sanitizers, or in food preparation situations, where bacteria from some types of food could contribute to sickness or even death.
"When someone is chopping a raw chicken, it splatters everywhere. Taking a damp sponge and wiping the counter down isn't going to necessarily eliminate harmful bacteria such as Salmonella or Campylobacter," said Cole. "In reality, what the person has just done is smeared the bacteria everywhere with the sponge. Here's an instance where a spray-on antibacterial sanitizer would be very useful and effective."
Cole also calls on manufacturers of antibacterial products to be responsible in how they label their products and the amount of active ingredients they include in their cleansers.
"Some manufacturers, just for a marketing advantage, will promote the fact that a product has antibacterial properties, but they don't include enough of the agent to really make a difference -- to leave a residual on the hands or a counter to suppress bacterial growth," said Cole. "There is a concern that killing those bacteria that are susceptible to these low concentrations of active ingredient are selecting for more antibacterial-resistant strains of bacteria, similar to what occurs with antibiotic resistance."
To avoid this possibility entirely, Cole recommends using products whose active ingredients are at a high enough level. Because manufacturers aren't always required to detail the amount of active ingredient they've included in any particular product, in general, he says consumers are safest with products that have built a consistent and good reputation in the cleaning product industry for their effectiveness. Additionally, consumers can contact manufacturers directly with questions about product content or educate themselves about the types and proper use of cleaning and related products on the Internet, such as the Soap and Detergent Association's Web site at www.sdahq.org
Joining Cole in the study are R. M. Addison, K. E. Leese, P. D. Dulaney, M. S. Newell, J. Wilkins, T. Wineinger and D.A. Criger of DynCorp Health Research Services in Morrisville, N.C.; and J. R. Rubino and D.J. Gaber of Reckitt Benckiser, Inc., in Montvale, N.J.