Some bacteria in your mouth can divide into 14 cells at once

Among the more than 500 species of bacteria that thrive in the human mouth, one seems to play by its own rules.

Instead of reproducing by dividing into two, as most bacteria do, Corynebacterium matruchotii divides into 14 cells simultaneously, researchers report on Sept. 10. Proceedings of the National Academy of Sciences.

C. matruchotii is a filamentous bacterium known to reside in plaque near the gum line. Microbiologist Scott Chimileski of the Marine Biological Laboratory in Woods Hole, Mass., observed cells dividing prolifically as he and colleagues used time-lapse imaging to study living microbial communities in the human mouth (SN: 7/11/16).

“As soon as he presented the find, we thought, ‘Oh my God! This is absolutely amazing,” says study co-author Gary Borisy, a microbiologist at the Forsyth ADA Institute in Cambridge, Mass.

Some other types of bacteria can divide many times at a time to generate spores – dormant cells that can later become active daughter cells. But no other known species divides into multiple daughter cells that then begin to grow and divide at once, the researchers say.

The unique reproductive strategy may allow C. matruchotii to quickly claim many territories. “When we brush our teeth, we clean the bacteria. But the next day, it’s back,” says Borisy. “We think it just crawls by rapidly expanding into fresh territory.”

The team then plans to study how C. matruchotii forms a biofilm to which other bacteria in the mouth attach, which can have implications for oral health.