Posted on September 13, 2016 at 2:06 AM
by Craig Klugman, Ph.D.
This month, the Food & Drug Administration (FDA) issued a final ruling that certain 19 chemicals used in making “antibacterial soaps and body washes” should be removed from those products. The added chemicals have neither been shown to be safe for daily use nor proven to be any more effective than regular soap and water. While this might seem to be a consumer issue—that the “antibacterial soap” label will disappear from store shelves, it is actually a public health ethics issue related to protecting people from harm both now and in the future.
I remember when these soaps and washes first appeared on the market. As someone who majored in bio-cultural evolution in college, I was interested in modern examples of evolution. Certainly, the selective pressure on bacteria from antibiotics is one of them. Consider that a person prescribed an antibiotic and feels better after 4 days so discontinues and does not complete the full 10-day regimen. The result is that the most susceptible bacteria die but the hardy ones resist and proliferate once the antibiotic is gone. Their “hardy” genes are then found in a greater proportion of the next generation and resistance has set in. Such natural selection is nothing more than a change in gene frequency. Given the rapid generations of bacteria, this sort of change occurs quickly. Most likely, that person will get sick again, a few weeks later.
When one considers the selective pressure that an antibacterial chemical in soap, the chances for resistance increase. This raises three issues: 1. Who rarely washes their hands for the full recommended 20 seconds of rigorous handwashing . Like taking less then the full dose, this is more likely to kill the weaker bacteria and leave the hardier ones behind. 2. Some of these chemical agents have been used for a long time and many common bacteria are known to be resistant to them. Thus, the chemical provides no benefit against several bacteria. 3. After rinsing your hands, the antibacterial agents drain into wastewater and possibly the water supply. The result of these chemicals is harm to the environment and if they leech into the water supply, we drink them.
If you don’t believe that resistance through natural selection does not happen quickly, I suggest you watch this Harvard video where bacteria become resistant to antibiotics in the lab.
My very first academic presentation was at an American Public Health Association meeting nearly 20 years ago where I presented on antibiotic resistance as public health issue and an ethics issue. Among my examples the use of antibiotics in animal feed and in soaps as places where these agents were used unnecessarily and posed a risk to human health. That risk is short, medium and long term.
The short-term risk to our health comes from the antibacterial chemicals themselves. For example, one of the most common antibacterial compounds is triclosan, which the FDA classifies as a pesticide. Rubbing that antibacterial soap into your skin means you are rubbing a pesticide into your skin. Triclosan is good at preventing bacteria from contaminating a surface, which is why it is also often found in cooking implements, furniture and toys. The FDA is conducting research on the effects of triclosan on the human body and will develop recommendations for its use.
A medium-term harm may come from overuse of these products. When my sister had her first child nearly 11 years ago, one could not touch my niece without first using antibacterial soaps or lotions. Everything the baby touched had to be sterilized and she certainly was not allowed to play in the dirt. My niece has allergy and asthma problems and though there is likely a genetic component to this, studies suggest that the lack of exposure to germs may actually prevent the development of a robust immune system. The increase of allergies and severe reactions to environmental stimuli that we are witnessing may be a result of not enough dirt. The microbial deprivation hypothesis suggests that we need to be exposed to germs and dirt in order to build a robust and properly functioning immune system. With my second niece I did take her to run around the park and even let eat dirt if she wanted (sorry, sis).
A longer-term risk is antibiotic resistance. This year, the US saw its first patient infected with e-Coli that carried the mcr-1 plasmid, which carries resistance to all known antibiotic agents. This is the “superbug” that has been all over the news. The danger of plasmids is that bacteria tend to exchange them. If one bacterium is resistant and has an advantage, then it’s only a matter of time until that gene makes it way into other bacterial species. A “post-antibiotic world” (according to CDC director Thomas Frieden) where common infections more easily kill is a scary prospect. The answer is to limit our use of antibiotics and when we develop new ones, to strictly control their use. If an antibiotic is used widely (like in soap or given to cattle) then it’s only a matter of time before resistance to that drug also develops.
As I tell my students, every choice one makes is an ethical decision. I chose never to buy a soap or wash that proclaimed its antibacterial properties. When an issue is one of individual health or choice, then such ethical decisions are sufficient. But when the issue expands to effect an entire population and the environment, then a public health intervention by the government is necessary. The FDA made a good call here, though it would have been better 20 years ago.