In vitro production of human fecal mutagen.

The feces of some normal humans were previously shown to be mutagenic by the Salmonella mutagenicity assay with strain TA100. In the present study, the mutagenicity of feces of certain donors can be increased by anaerobic incubation for 96 h. The increase in mutagenicity did not occur upon incubation in the cold or in air, in the presence of antimicrobial agents or if the feces were sterilized by heat. On thin-layer chromatographs, the relative mobility of fecal mutagen for all donors after incubation was the same in any one of 4 different solvent systems. The major mutagenicity appears to be due to a single type of compound which may be produced by anaerobic bacteria.