Hydrogen sulfide-producing bacteria in tongue.pdf

Journal of Medical Microbiology (2005), 54, 889–895 DOI 10.1099/jmm.0.46118-0 46118 2005 SGM Printed in Great Britain 889 Correspondence Nobuhiro Takahashi nobu-t@mail.tains.tohoku.ac.jp Received 12 April 2005 Accepted 1 June 2005 Hydrogen sulfide-producing bacteria in tongue biofilm and their relationship with oral malodour Jumpei Washio,1,2 Takuichi Sato,2 Takeyoshi Koseki1 and Nobuhiro Takahashi2 1,2Division of Preventive Dentistry1, and Division of Oral Ecology and Biochemistry2, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan The aims of this study were to identify hydrogen sulfide (H2S)-producing bacteria among tongue biofilmmicroflora and to investigate the relationship between bacterial flora andH2S levels in mouth air. Oral malodour levels in 10 subjects (age 21–56 years) were assessed by gas chromatography, and Breathtron and organoleptic scores. Based on these assessments, subjects were divided into two groups: an odour group and a no/low odour group. Tongue coatings were sampled and spread onto Fastidious Anaerobe Agar plates containing 0.05% cysteine, 0.12% glutathione and 0.02% lead acetate, and were then incubated anaerobically at 37 8C for 2 weeks. Bacteria forming black or grey colonies were selected as H2S-producing phenotypes. The numbers of total bacteria (P , 0.005) and H2S-producing bacteria (P , 0.05) in the odour group were significantly larger than those in the no/low odour group. Bacteria forming black or grey colonies (126 isolates from the odour group; 242 isolates from the no/low odour group) were subcultured, confirmed as producing H2S and identified according to 16S rRNA gene sequencing. Species of Veillonella (38.1% in odour group; 46.3% in no/low odour group), Actinomyces (25.4 %; 17.7%) and Prevotella (10.3%; 7.8%) were the predominant H2S-producing bacteria in both the odour and no/low odour groups. These results suggest that an increase in the number of H2S-producing bacteria in t