For tooth decay microbes, many routes lead to kids’ mouths

BOSTON — Moms get blamed for a lot — including their kids’ cavities. But new data show that the most common cause of tooth decay, the bacterium Streptococcus mutans, doesn’t always come from mother-to-child transmission.

Researchers from the University of Alabama at Birmingham studied 119 children in rural Alabama and 414 of their household contacts, tracking the path of S. mutans. Contrary to expectation, 40 percent of the children did not share any strains with their mothers. Instead, those strains usually overlapped with those of siblings and cousins. And 72 percent of children carried a strain of S. mutans that no one else in the family had, probably picked up from other children at school, day care or other locations. The research was presented June 17 at ASM Microbe 2016, a meeting of the American Society for Microbiology and the Interscience Conference on Antimicrobial Agents and Chemotherapy.

While maternal transmission was still the most common route, “we’re not trying to say ‘Don’t kiss your babies,’” said Stephanie Momeni, a doctoral candidate at UAB. Rather, the ultimate goal of the research is to learn whether particular strains of S. mutans pose a greater hazard for dental health. Knowing that would help identify children who might be in need of more aggressive dental hygiene.