In a world where illness lurks in every bathroom stall and on every subway strap, antibacterial soaps give people a sense of control, a sudsy security blanket. But not anymore. Today the Food and Drug Administration announced that it is pulling a wide range of antimicrobial soaps from the market, citing a lack of evidence that they work–and reinforcing the idea that they actually might exacerbate the looming threat of antibiotic resistance.
The FDA first proposed the ban on antimicrobial soaps back in 2013. Since then, it’s asked soap manufacturers to submit data showing their products did a better job of keeping disease-causing germs out of the body than plain soap and water, without adverse health effects. The agency found the results either incomplete or unconvincing. “We didn’t get confirmation that these products are harmful,” said FDA spokeswoman Andrea Fischer. “But there’s not enough data to make the case for their effectiveness.” The takeaway: Stick to washing your hands with good ol’ soap and water.
The antimicrobial triclosan was introduced to hospitals back in the 1960s, but by the 80s, soap marketers saw an opportunity to get in households all across the US: by offering a promise of everyday protection to consumers. But most of the sicknesses people commonly come down with–colds, stomach flus, sore throats–are caused by viruses, not bacteria. “The evidence is strong that these products don’t reduce infectious illnesses,” says Allison Aiello, a professor of epidemiology at the Gillings School of Public Health in Chapel Hill who has studied triclosan for years. Bacterial concerns like salmonella and E. coli are commonly found on food, and hand-washing won’t make any difference there.
Lastly, and most importantly, triclosan and chemicals like it are rarely present in high enough concentrations in consumer products to kill all the bacteria on your skin. At these low concentrations, they instead exert selective pressure on bacteria, allowing them to quickly evolve adaptations–like one cellular mechanism that sucks in triclosan and pumps it right back out, almost like a gag reflex. Add up these adaptations and you get bacterial resistance, which gets passed down genetically, and eventually you get…our future superbug overlords. “You can contribute to sublethal exposure ,” says Aiello, “and then you’ve got a pretty dangerous situation on your hands in terms of changing antibiotic resistance.”
The new FDA ban will help remove some of that evolutionary pressure on the world’s microbes. Starting September 2017, hand soaps and body washes can no longer contain triclosan, triclocarban, or any of 17 other specific chemicals with germ-killing properties. Manufacturers have until then to either reformulate their products or yank them from the market completely. The ruling does not affect triclosan-containing antiseptic products used in hospitals and other health care settings, or alcohol-based hand sanitizers, which the FDA is reviewing separately. Rulings for those are slated for 2018 and 2019, respectively.
In the meantime, there’s every reason to think that normal soap is still a great defense against infection–and it’s actually a method that can inform future strategies against bugs. While the classic combination doesn’t kill germs, it does mechanically remove them from your hands, with the help of a bit of chemistry. Basic soaps are composed of water-soluble fatty acid potassium salts. Imagine a negatively charged “head” that is hydrophilic, or water-loving. It’s attached to a long hydrophobic hydrocarbon chain. When you’re washing your hands, the tail grabs on to organic compounds like soil, food, bacteria, and viruses–and the head pulls all that stuff away from your skin, disrupting the microbe’s ability to latch on again. Now trapped in fat-on-the-inside, water-on-the-outside globules, the microbes get easily washed down the drain.
It’s a pretty smart strategy. So rather than focusing on killing them all, what if we concentrated on just keeping bacteria and viruses off things? Like extra-bacteria-philic soaps? High-tech hospital surfaces that mimic shark skin, preventing the growth of dangerous bacteria? Or what about engineering materials to keep bacteria from sticking to them completely? Creativity beyond bacterial cluster-bombing is long overdue. Scientists are thanking the FDA for the push, even if soap manufacturers aren’t.
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The FDA’s Antibacterial Soap Ban Is Bad News for Superbugs
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