Volatile sulfur compounds produced by Helicobacter pylori

Goals: To assess the volatile sulfur compounds produced by three strains of Helicobacter pylori in broth cultures mixed with sulfur-containing amino acids. Background: Halitosis has been reported in H. pylori-positive patients, and volatile sulfur compounds such as hydrogen sulfide and methyl mercaptan are known to be responsible for inducing oral malodor. Whether H. pylori produces these volatile sulfur compounds has yet to be established. Study: Three strains of H. pylori (ATCC 43504, SS 1, DSM 4867) were cultured with 5 mM cysteine and methionine. After 72 hours of incubation, the headspace air was aspirated and injected directly into a gas chromatograph. The concentrations of hydrogen sulfide and methyl mercaptan were analyzed and compared between experimental and control cultures Results: In broth containing 5 mM eysteine, hydrogen sulfide was increased by ATCC 43504 (P < 0.01) and SS 1 (P < 0.05), while methyl mercaptan was elevated only by SS I (P < 0.05). In broth containing 5 mM methionine, methyl mercaptan increases were significant for SS I (P < 0.05) and DSM 4867 (P < 0.05). In broth containing 5 mM cysteine and 5 mM methionine, the concentration of hydrogen sulfide was higher than in controls for all three strains (P<0.01); that of methyl mercaptan was higher only for SS I (P<0.01). Cysteine addition to cultures containing methionine increased hydrogen sulfide and methyl mercaptan for ATCC 43504 (P<0.05) and SS I (P<0.05). Conversely, addition of methionine to cultures containing cysteine increased methyl mereaptan only for DSM 4867 (P < 0.01). Conclusions: The production of volatile sulfur compounds by H. pylori is not only very complicated but also strain-specific. Nevertheless, H. pylori was shown to produce hydrogen sulfide and methyl mercaptan, which suggests that this microorganism can contribute to the development of halitosis.