Some Observations on a Perigo-Type Inhibition of Clostridium botulinum in a Simplified Medium

Abstract

A rapid and sensitive assay for Perigo factor was developed using a medium of 0.5% yeast extract and tryptone, 0.2% glucose, 0.12% K2HPO4 and 0.1% cysteine HCI or sodium thioglycollate and vegetative cells of Clostridium botulinum type A. Yeast extract or tryptone, together with a reducing agent (cysteine, sodium thioglycollate, or glucose autoclaved with the medium), produced a Perigo inhibitor when autoclaved at 15 psi for 15 min with NaNO2. Tryptone was more active than yeast extract as a source of the Perigo inhibitor; of the reducing agents tested cysteine was more effective in producing Perigo-type inhibition than thioglycollate and either was better than glucose autoclaved with the medium.