Common antimicrobial agent disrupts gut bacteria

A new study suggests that an antimicrobial and antifungal agent found in many consumer products ranging from hand soaps to toys and toothpaste can rapidly disrupt bacterial communities found in the gut.

The finding about triclosan, which was first used as a hospital scrub in the 1970s and now is one of the most common antimicrobial agents in the world, were published Wednesday in PLOS ONE by researchers from Oregon State University.

It was based on study made with zebrafish, which the researchers believe are an important animal model to help determine possible human biological and health impacts of this antimicrobial compound.

As triclosan is used in medical settings and in shampoos, deodorants, toothpastes, mouth washes, kitchen utensils, cutting boards, toys, bedding, socks and trash bags, it can be absorbed through the skin.

In the study, the researchers found that triclosan exposure caused rapid changes in both the diversity and composition of the microbiome in the laboratory animals.

"There has been a legacy of concern about exposure to microbial pathogens, which has led to increased use of these antimicrobial products," said Thomas Sharpton, an assistant professor of microbiology and statistics at the OSU Colleges of Science and Agricultural Sciences, and corresponding author on the study.

"However, there's now a growing awareness of the importance of the bacteria in our gut microbiome for human health, and the overuse of antibiotics that can lead to the rise of 'superbugs.' There are consequences to constantly trying to kill the bacteria in the world around us, aspects we' re just beginning to understand," Sharpton noted.

It is not clear what the implication of triclosan may be for animal or human health, but the science community believes that compromising of the bacteria in the intestinal tract may contribute to the development or severity of disease.

"Clearly there may be situations where antibacterial agents are needed," said Christopher Gaulke, lead author on the study and a postdoctoral microbiology researcher in the OSU College of Science. "Scientists now have evidence that intestinal bacteria may have metabolic, cardiovascular, autoimmune and neurological impacts, and concerns about overuse of these agents are valid."

The gut-associated microbiome performs vital functions for human health, prevents colonization with pathogens, stimulates the development of the immune system, and produces micronutrients needed by the host. Dysfunction of this microbiome has been associated with human disease, including diabetes, heart disease, arthritis and malnutrition.

Humans are routinely exposed to an array of chemicals, metals, preservatives, microbes and nutrients, some of which may be beneficial, some innocuous, and others harmful, the researchers said. Endit