Hand Soap Ingredient Can Up Body Bacteria Burden

Residues of the antimicrobial agent triclosan can paradoxically boost bacterial growth in our bodies, by giving microbes a comfortable biofilm in which to rest. Christopher Intagliata reports

 

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


The antimicrobial triclosan is a common ingredient in hand soap. But it's also found in shampoos, deodorants, toothpaste, even lip gloss. So it's not too surprising that triclosan also shows up in blood, urine, breast milk and mucus. But here's the weird thing—those triclosan residues may actually boost bacterial growth in our bodies. So says a study in the journal mBio. [Adnan K. Syed et al, Triclosan Promotes Staphylococcus aureus Nasal Colonization]

Researchers swabbed inside the noses of 90 adults. 37 of the 90 tested positive for triclosan—and those who did were twice as likely to have the bug Staphylococcus aureus living in their noses. Rats, too, were more susceptible to staph if fed triclosan.
 
Seems counterintuitive, but when bacteria are exposed to sublethal levels of antibiotics, they get stressed, and “they attach to surfaces and hunker down, in things we call biofilms." That's study author Blaise Boles, of the University of Michigan.

He says that stash of staph could put your health at risk. "Individuals that have Staph. aureus in their nose before they undergo surgery are about seven times more likely to get a Staph. aureus surgical site infection." Which is when you'll really need those antibiotics.

—Christopher Intagliata

[The above text is a transcript of this podcast.]
 

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe