While past research has connected oral malodor to the proliferation of certain bacteria on the tongue, recent research from the Forsyth Institute and the University of Michigan School of Dentistry indicates another group of bacteria is associated with fresh-smelling breath. Investigators used gene sequencing to compare bacteria found on the tongues of individuals with halitosis and those with fresh breath. While not all samples taken from halitosis sufferers had the same bacterial makeup, three particular strains — Streptococcus salivarius, Rothia mucilaginosa and a previously uncharacterized strain of Eubacterium — were the most prevalent species on the tongues of subjects with fresh breath. From the American Dental Association:Study identifies ‘good’ and ‘bad’ breath bacteria
While past research has connected oral malodor to the proliferation of certain bacteria on the tongue, recent research from the Forsyth Institute and the University of Michigan School of Dentistry indicates another group of bacteria is associated with fresh-smelling breath.
Investigators used gene sequencing to compare bacteria found on the tongues of individuals with halitosis and those with fresh breath. While not all samples taken from halitosis sufferers had the same bacterial makeup, three particular strains?Streptococcus salivarius, Rothia mucilaginosa and a previously uncharacterized strain of Eubacterium?were the most prevalent species on the tongues of subjects with fresh breath.
The most prevalent bacterium found in the fresh-breathed subjects, Streptococcus salivarius, was found in only one individual with oral malodor and at very low levels, the investigators reported.
The study also identified six species of bacteria most associated with halitosis: Atopobium parvulum; a phylotype of Dialister; Eubacterium sulci; a phylotype of the as yet uncultivated phylum TM7; Solobacterium moorei; and a phylotype of Streptococcus.
?In each of six individuals with halitosis, we found several species that were not found in those with fresh breath,? said Bruce Paster, Ph.D., Forsyth senior staff member. ?Conversely, in five individuals with fresh breath, we identified species not generally found in those with halitosis. These findings would suggest that certain bacteria are associated with bad breath, and that others, the normal microflora, protect against it.?
The Forsyth study is part of an ongoing effort to determine genetic sequences for all species of bacteria that colonize the oral cavity. In the current molecular analysis of tongue scrapings, scientists have found 92 bacterial species, of which 29 have never before been described in the scientific literature.