Biochemical classification of Clostridium botulinum type C and D strains and their nontoxigenic derivatives.

The biochemical properties of 11 toxigenic and 10 nontoxigenic type C and D strains of Clostridium botulinum were studied. All of the strains examined were motile and hemolytic and produced lipase and liquid gelatin. Fermentation of several sugars and the production of lecithinase, indole, and hydrogen sulfide varied with the strain. The strains were classified into four groups based on their sugar fermentation profiles. The resulting classification was identical to the classification which had been proposed from the relationship between toxin production and phages and similar to the grouping based on the nature of toxin antigenic structures. Lecithinase production was negative in the cells belonging to group III, and indole and hydrogen sulfide production was negative in the cells of groups III and IV. Strains belonging to groups III and IV have many characteristics different from those of groups I and II.