Influence of a methanogenic flora on the breath H2 and symptom response to ingestion of sorbitol or oat fiber.

BACKGROUND AND OBJECTIVES: We investigated the possibility that a variant of the normal colonic flora, a high concentration of methanogens, influences the host's response to ingestion of nonabsorbable, fermentable materials. METHODS: To better evaluate symptomatic and breath H2 and methane (CH4) responses, subjects were placed on a basal diet (primarily rice and hamburger) that contained minimal amounts of nonabsorbable, fermentable substrate. A breath CH4/H2 ratio of greater or less than 1 on the second day of the basal diet was used to categorize subjects as high (N = 9) or low (N = 25) CH4 producers. After stabilization of the breath gas excretion (day 3 or 4 on the basal diet), the subjects ingested either sorbitol (8.8 g) or oat fiber (10.2 g). RESULTS: The low CH4 producers had a significantly higher (p < 0.05) breath H2 concentration than the high producers on the basal diet and after ingestion of sorbitol (27.1 +/- 2.7 ppm vs 15.8 +/- 3.6 ppm) or oat fiber (13.1 +/- 0.08 ppm vs 9.6 +/- 1.2 ppm). Low producers of methane reported significantly increased bloating and cramping after sorbitol ingestion and increased bloating after fiber ingestion, whereas high CH4 producers reported no significant increase in these symptoms. CONCLUSION: The presence of a methanogenic flora is associated with a reduced symptomatic response to ingestion of nonabsorbable, fermentable material in healthy subjects. Manipulation of the normal flora could be of therapeutic value in nonmethanogenic patients with irritable bowel syndrome.

Reduction of oral microbes by a single chlorhexidine rinse.

Because of the continued threat of human immunodeficiency virus and hepatitis B infection, as well as the possibility of cross-infection from microbes, such as the herpesviruses and staphylococci, infection control remains a critical issue in dentistry. A traditional response to the infection-control issue is the use of barrier protection by the practitioner and staff. Little attention has been paid to reducing the number of potential pathogens in the oral cavity before dental procedures as a means of minimizing the potential spread of contagion between patients and treatment providers. A study to determine the effectiveness and duration of a single rinse with 0.12% chlorhexidine gluconate oral antiseptic in reducing the number of microorganisms in the oral cavity is presented.