Influence of the bacterial flora of the gut on sulfur amino acid degradation. A study of patients with bacterial overgrowth before and during treatment with oxytetracycline or metronidazole.

The urinary excretion of sulfur amino acids and their main degradation products was determined in 10 patients with bacterial overgrowth during treatment with oxytetracycline or metronidazole. A normal excretion of total sulfur and inorganic sulfate was found during treatment with both antibiotics, indicating a normal intake, uptake, and oxidation of sulfur amino acids to inorganic sulfate. Irrespective of type of antibiotic given, a normalization of the increased ester sulfate excretion was found, favoring the opinion that both the aerobic and anaerobic flora of the gut contribute to the formation of sulfate esters. The cystathioninuria found in patients with bacterial overgrowth was normalized only by treatment with metronidazole. Both antibiotics resulted in a reduced excretion of taurine and thiosulfate, but especially for thiosulfate, the effect of metronidazole treatment was more pronounced. The results suggest that the bacterial flora of the gut, such as anaerobes, may be of importance in the formation of thiosulfate in the human body.