In vitro volatile sulfur compound production of oral bacteria in differentculture media

Objective: The purpose of this study was to detect the relative contributio n of Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella inte rmedia in the production of oral malodor. Method and materials: The volatil e sulfur compounds produced by these bacteria in vitro were measured semiqu antitatively by a portable sulfide monitor. Results: Samples from the tongu e, tonsils, and pharynx showed a significantly higher production (550 ppb) of volatile sulfur compounds during the first 6 hours after anaerobic incub ation in broths (brain-heart infusion, Columbia, and Trypticase Soy) than a fter incubation in agar media (300 ppb) (P < 0.001). After 24 hours, values in broths and agars leveled off at 350 ppb (P = 0.3) and remained constant during the next 6 days. Measurement of separate pure cultures showed that maximal volatile sulfur compound production was reached 6 hours after incub ation (450 ppb for the 3 bacteria). Higher volatile sulfur compound Values were measured in brain-heart infusion. When measurements of mixed cultures of the 3 pathogens were performed every 15 minutes, the maximal value was r eached after only 30 minutes of incubation (nearly 500 ppb). Conclusion: Th e in vitro volatile sulfur compound production of oral samples is preferabl y measured in broths. Maximal sulfur production from mixed cultures is reac hed after 30 minutes of incubation. Samples should always be inoculated at the same dilution.