Monday, March 17, 2003

My most recent unqualified recommendations about public health.....
Wash That Advertising Away
Just Say "No" to anti-bacterial soap
. . . by Ari Johnson
[Illustration by Tavet Gillson]

They have probably already invaded your home. They are soaked into your sponges, smothering your countertops. They are covering your skin. They are all over your kitchen and bathroom appliances and utensils. They may even be in your clothes, and on your children’s toys.

And they may be dangerous.

They’re called anti-bacterials.

In the early 90s, there were only a few dozen cleaning products on the market with chemicals especially designed to kill bacteria—microscopic one-celled life. By 2000, more than 700 bacteria-killing products graced the shelves of “Soaps and Cleansers” aisles.

Now, antibacterial chemicals have seeped into every room in the house; they are marketed for a wide array of products including mattresses, chopsticks, clothing, bathroom and kitchen appliances, and children’s toys.
Labels boast claims like “Kill more germs to keep you and your family healthier.” In commercials, bacteria are belittled as ubiquitous and dangerous invaders that responsible home-makers must destroy.

But such demonization is perhaps better fitted to the antimicrobial products than to the bacteria they claim to destroy. Antibacterial products are unproven in their usefulness, and they may even pose a threat to personal and public health.

Together forever, that’s how it must be
The lives of bacteria and humans are intimately intertwined. Bacteria in the human body outnumber human cells ten to one. Humans host immense communities of bacteria, especially along the skin, mouth, and digestive tract.
Only a small fraction of bacterial strains actually make us sick. Many are harmless. Some are actually helpful—they make their homes in our bodies and often out-compete other invaders that might otherwise have caused disease.
Medicine has recognized the protective properties of certain harmless bacteria, which has spurred the emergence of “probiotics,” a treatment in which essential bacteria are administered to protect humans from infection. This procedure is particularly useful to people who have just finished an antibiotic treatment that has weakened indigenous bacterial communities essential to health.

Humans count on bacteria for certain vital functions, including digestion, production of vitamin K, and sensitization of the immune system. Studies done by proponents of the “hygiene hypothesis” have shown that lack of sufficient exposure to bacteria can lead to immune-deficiency related to problems such as allergies, asthma and eczema.
Yet we continue to associate bacteria with causing disease. We persist in quixotic efforts to rid them from our lives, though such a goal is as futile as it is undesirable.

Resistance is futile
Bacteria are perhaps the most enduring and successful living things on this planet—they flourish everywhere, even in some of the most extreme environments, where no other living things can live.

“As competitors, microbes are unbeatable,” said Julian Davies, President of the American Society of Microbiology.
Bacteria are unbeatable because they are master evolvers. High gene mutation rates allow for rapid changes in traits from generation to generation. But they do not have to wait until reproduction to change their genetic makeup; bacteria can pick up and trade traits packed in genetic suitcases called plasmids. This is just one of an array of tools bacteria harness to acquire genes from other bacteria, as well as from plants, animals, and the environment.
Imagine picking up genes from an apple, or exchanging genes in a handshake. Such rapid and extreme genetic flexibility allows bacterial populations to rapidly acquire and spread traits that help them survive in a particular context.

Bacteria possess the evolutionary tools to survive, often in spite of our best attempts to eradicate them. The impossibility of removing bacteria ceases to be a tragedy once we acknowledge that complete bacterial extermination would be a terrible idea anyway.

There is madness behind the popular method
Perhaps the most surprising part of this story is that antibacterial products have not been proven to perform their purported functions in the home. Many of the studies documenting the bacteria-killing abilities of these products took place in laboratory and clinical settings, environments quite different from the home.

When used sporadically and quickly, and when diluted in household settings, antibacterial soaps have not been shown to effectively kill bacterial populations.

The Association for Professionals in Infection Control and Epidemiology (APIC) conducted a systematic study and analysis of current research literature and data provided by eleven different antibacterial-producing companies. “The literature yielded no scientific data supporting the use of antimicrobial agents in household products as a means to prevent infection,” the APIC report concluded.

Not to be outdone, the American Medical Association conducted its own comprehensive analysis of scientific studies and advised, “It is prudent to avoid the use of antimicrobial agents in consumer products.” They also urged the FDA to expedite its regulation of antibacterial products, in light of unproven efficacy and potential health risks.
Despite unproven claims and potential dangers, the craze over antibacterial household products is still rampant. This is foolishness.

To meet the mounting challenges of infectious disease and live healthfully, humans will need to abandon such delusions about bacteria and commit to living better with them, taking greater advantage of mutually advantageous relationships.

Household hygiene should promote human health. To do so, the concept of the bacteria-free home needs to be supplanted with an appreciation of the significance of bacterial communities to maintaining our health.

The final hour
So antibacterial products cannot be counted upon to make good on advertised promises. But are the promises of Lysol, Clorox, and Dial even worth pursuing? Killing bacteria en masse and trying to eradicate them from the home may turn out to be a pretty terrible idea.

If you put bacteria-killing products out into the home environment, you will, at best, succeed in killing the bacteria that are vulnerable to that product. Bacteria that can resist the attacks of these products will thus be encouraged to survive and reproduce.

The evolution, emergence, and proliferation of bacteria resistant to the attacks of antimicrobial products might seem only a concern for the producers of these bacteria-killing products. But a number of studies, including those of Stuart Levy’s lab at Tufts University, have shown that resistance to some antibacterial products can also help bacteria resist the attacks of several antibiotic medicines, including a drug commonly used as a tuberculosis treatment.
The “hygiene hypothesis” is still a hypothesis, and the extent of resistance spurred by antibacterial household products requires further study and substantiation. Still, the potential dangers of anti-bacterials, coupled with their generally unproven efficacy, should provide sufficient reason to opt for soaps and other household products without the “antibacterial” or “antimicrobial” label.

An evolutionary understanding of human-bacteria relationships should inspire new kinds of hygienic frontiers that capitalize on the potential protective effects of certain bacteria. Pro-bacterial soap, anyone?

Ari Johnson B’04 would like to thank the legions of bacteria that contributed to this article.