Antimicrobial Soaps Can Cause the Accumulation of Bacteria in the Human Nose

An antimicrobial agent found in common household soaps, shampoos and toothpastes can go inside the human nose where it promotes colonization by Staphylococcus aureus and may predispose individual to infection.Researchers at the University of Michigan report their findings this week in a study published in mBio ® , the online magazine and free access to the American Society for Microbiology.

Triclosan, a synthetic compound used in a range of personal care products such as antibacterial soaps, toothpaste, kitchen surfaces, clothing and medical equipment was found in the nasal passages of 41% of adults sampled A greater proportion of subjects with triclosan also had colonization by S. aureus . S. aureus may promote infection in some populations such as people undergoing surgery.

Triclosan has been around for 40 years, said the lead author of the study, Blaise Boles, assistant professor of molecular and cell biology and development at the university, and it has been incorporated into many antibacterial household products the last decade.

Other studies have found traces of triclosan in human fluids, such as serum, urine and milk, and studies in mammals showed that high concentrations of triclosan can disrupt the endocrine system and reduce cardiac function and skeletal muscle.

"  It's really common in hand soaps, toothpastes and mouthwashes, but there is no evidence, it is probably a better job than regular soap  , "says Boles. "  This agent may have unintended consequences in our bodies. It could promote the nasal colonization of S. aureus and do some people have an increased risk of infection.  "

Experiments have found that S. aureus cultured in the presence of triclosan were more capable of binding to human proteins, and that rats exposed to triclosan were more sensitive to nasal colonization by S. aureus .

"  Given the widespread use of triclosan in consumer products and widespread contamination in the environment, our data combined with previous studies showing the effects of triclosan on the endocrine system and muscle function suggest a reassessment triclosan in consumer products is urgently needed  , "the authors write.

Boles said he would conduct a more extensive investigation to determine whether triclosan affects microbial colonization in other sites in the body.