An antimicrobial agent found in common household soaps, shampoos and toothpastes may be finding its way inside human noses where it promotes the colonisation of infection-causing bacteria.
Triclosan, a man-made compound used in a range of antibacterial personal care products such as soaps, toothpastes, kitchen surfaces, clothes and medical equipment, was found in nasal passages of 41 per cent of adults sampled by researchers at the University of Michigan.
A higher proportion of subjects with triclosan also had S aureus colonisation.
S aureus could promote infection in some populations such as people undergoing surgery, researchers said.
Triclosan has been around for the past 40 years and has been incorporated into many antibacterial household products within the past decade, said senior study author Blaise Boles, an assistant professor of molecular, cellular and developmental biology at the university.
Other studies have found traces of triclosan in human fluids including serum, urine and milk, and studies in mammals have found that high concentrations of triclosan can disrupt the endocrine system and decrease heart and skeletal muscle function.
"It's really common in hand soaps, toothpastes and mouthwashes but there's no evidence it does a better job than regular soap," Boles said.
"This agent may have unintended consequences in our bodies. It could promote S aureus nasal colonisation, putting some people at increased risk for infection," Boles added.
Additional experiments found that S aureus grown in the presence of triclosan was better able to attach to human proteins, and that rats exposed to triclosan were more susceptible to S aureus nasal colonisation.
"In light of the significant use of triclosan in consumer products and its widespread environmental contamination, our data combined with previous studies showing impacts of triclosan on the endocrine system and muscle function suggest that a reevaluation of triclosan in consumer products is urgently needed," researchers said.
The study is published in mBio, the journal of the American Society for Microbiology.
