Molecular identification of bacteria on the tongue dorsum of subjects with and without halitosis


Dr Marcello Riggio, University of Glasgow Dental School, 378 Sauchiehall Street, Glasgow, G2 3JZ, UK. Tel: +44 141 211 9742, Fax: +44 141 353 1593,


Aim:  Compare the microbial profiles on the tongue dorsum in patients with halitosis and control subjects in a UK population using culture-independent techniques.

Materials and methods:  Halitosis patients were screened according to our recently developed recruitment protocol. Scrapings from the tongue dorsum were obtained for 12 control subjects and 20 halitosis patients. Bacteria were identified by PCR amplification, cloning and sequencing of 16S rRNA genes.

Results:  The predominant species found in the control samples were Lysobacter-type species, Streptococcus salivarius, Veillonella dispar, unidentified oral bacterium, Actinomyces odontolyticus, Atopobium parvulum and Veillonella atypica. In the halitosis samples, Lysobacter-type species, S. salivarius, Prevotella melaninogenica, unidentified oral bacterium, Prevotella veroralis and Prevotella pallens were the most commonly found species. For the control samples, 13–16 (4.7–5.8%) of 276 clones represented uncultured species, whereas in the halitosis samples, this proportion increased to 6.5–9.6% (36–53 of 553 clones). In the control samples, 22 (8.0%) of 276 clones represented potentially novel phylotypes, and in the halitosis samples, this figure was 39 (7.1%) of 553 clones.

Conclusions:  The microflora associated with the tongue dorsum is complex in both the control and halitosis groups, but several key species predominate in both groups.