Neptune Bacteria News™
Your daily gob of toothpaste or spritz of body spray might be inadvertently mucking up your antibiotic treatment, suggests new research. It found that a common household antimicrobial ingredient—triclosan—seemed to reduce the potency of antibiotics used to treat urinary tract infections by a hundred-fold, at least in mice.
Triclosan is an ubiquitous chemical, found in everything from body wash to lip gloss to deodorant to household cleaners to mouthwash. Traditionally, it’s been advertised as an easy way to kill bacteria and fungi, seemingly without harm to humans. In recent years, though, increasing evidence has suggested otherwise.
In 2017, the Food and Drug Administration finalized its ban of triclosan and similar chemicals from being used in consumer soaps marketed as antimicrobial. The agency cited evidence showing antimicrobial soaps with these ingredients don’t seem to prevent illness or even kill bacteria any better than a typical bar of soap and hot water. Even more worrying is a growing pile of research showing that triclosan can actually help create bacterial superbugs.
It’s thought that the way triclosan stops bacteria is too similar to how many antibiotics do the job. So bacteria that evolve resistance to triclosan also learn how to fend off those drugs. That’s definitely bad news, because triclosan eventually ends up everywhere in our environment, where it can promote broad antibiotic resistance.
The new study, published in Antimicrobial Agents and Chemotherapy, doesn’t break new ground in proving this connection. But the results suggest that the effects of triclosan on antibiotics and bacteria happen long before the chemical escapes into the outside world—it can happen inside our bodies, too.
The researchers first exposed petri dishes containing strains of UTI-causing Escherichia coli and methicillin-resistant Staphylococcus aureus (the superbug also called MRSA) to doses of triclosan that you’d typically find in a consumer product. Then they tried to use common, bacteria-killing antibiotics on them. Compared to non-exposed bacteria, the triclosan-battered bacteria were able to tolerate the antibiotics 1,000 times better. The team next did a similar experiment with live mice, finding that bacteria exposed to triclosan could survive in mice up to 100 times better than the control germs.
“Normally, one in a million cells survive antibiotics, and a functioning immune system can control them. But triclosan was shifting the number of cells,” lead author Petra Levin, a professor of biology at Washington University, said in a statement. “Instead of only one in a million bacteria surviving, one in 10 organisms survived after 20 hours. Now, the immune system is overwhelmed.”
gizmodo.com
