Hydrogen sulfide-producing bacteria in tongue biofilm and their relationship with oral malodour

• Published in: Journal of medical microbiology Vol. 54; no. 9; pp. 889 - 895
• Main Authors: Washio, Jumpei, Sato, Takuichi, Koseki, Takeyoshi, Takahashi, Nobuhiro
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.09.2005; Society for General Microbiology
• Subjects: Adult; Biofilms - growth & development; Biological and medical sciences; DNA, Bacterial - analysis; Female; Fundamental and applied biological sciences. Psychology; Gram-Negative Bacteria - classification; Gram-Negative Bacteria - genetics; Gram-Negative Bacteria - isolation & purification; Gram-Negative Bacteria - metabolism; Gram-Positive Bacteria - classification; Gram-Positive Bacteria - genetics; Gram-Positive Bacteria - isolation & purification; Gram-Positive Bacteria - metabolism; Halitosis - microbiology; Humans; Hydrogen Sulfide - metabolism; Infectious diseases; Male; Medical sciences; Microbiology; Middle Aged; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; Tongue - microbiology; Microbiology; Biofilm; Hydrogen bacteria
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.46118-0

1,2 Division of Preventive Dentistry 1 , and Division of Oral Ecology and Biochemistry 2 , Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan Correspondence Nobuhiro Takahashi nobu-t{at}mail.tains.tohoku.ac.jp Received April 12, 2005 Accepted June 1, 2005 The aims of this study were to identify hydrogen sulfide (H 2 S)-producing bacteria among tongue biofilm microflora and to investigate the relationship between bacterial flora and H 2 S 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 °C for 2 weeks. Bacteria forming black or grey colonies were selected as H 2 S-producing phenotypes. The numbers of total bacteria ( P < 0.005) and H 2 S-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 H 2 S 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 H 2 S-producing bacteria in both the odour and no/low odour groups. These results suggest that an increase in the number of H 2 S-producing bacteria in the tongue biofilm is responsible for oral malodour, although the bacterial composition of tongue biofilm was similar between the two groups. Abbreviation: VSC, volatile sulfur compound.