Ingredient in toothpaste, mouthwash may cause antibiotic resistance

Triclosan, an antimicrobial chemical used in toothpastes and mouthwash, may reduce the effectiveness of some antibiotic drugs by 100-fold, says a new study by researchers at Washington University in the United States.

The new study involving mice found that triclosan in the bloodstream made bactericidal antibiotics significantly less effective. Antibiotics like triclosan kill bacterial cells rather than simply inhibiting their growth. Normally, one in a million bacterial cells survive antibiotics, but a functioning immune system can control them.

However, constant use of triclosan was found to shift the number of bacterial cells that can survive. Instead of only one in a million bacteria surviving, triclosan upped the figure to one in ten organisms surviving after 20 hours and overwhelming the immune system.

Triclosan created antibiotic resistance in a wide range of antibiotics, but the most notable was ciprofloxacin (brand name Cipro), commonly used to treat urinary tract infections (UTIs). That is a potential recipe for disaster as Cipro is a first-line treatment for UTIs, which is common infection among the general public.

In fact, the researchers found 100 times more bacteria in mice treated for UTIs who drank water dosed with triclosan compared to those that were not exposed to the antibacterial compound.

Evidence of triclosan’s potential negative effects — from endocrine disruption to reduce sperm count to the creation of antibiotic ‘superbugs’ — led the Food and Drug Administration (FDA) in the US to tell companies to stop marketing hand and bar soaps as well as body washes that contain the compound back in 2016. But that recommendation did not extend to toothpastes and mouthwashes, where triclosan use persists.