The Differentiation of Various Strains ofClostridium botulinumand Transformation Experiments with Type E

摘要

The colonial forms and other characteristics of toxigenic and less toxigenic (hypotoxigenic) variants ofClostridium botulinumtypes A, B, C, D and E are described. In addition to differences in the appearance of the colonies the hypotoxigenic variants were able to produce larger numbers of spores. Transformation from one form to the other was found when they were grown in Robertson's meat broth to which sterile culture filtrates (boiled or unboiled) from the other form was added. A transformation from hypotoxigenic variants to toxigenic forms was also found when hypotoxigenic forms were grown in Robertson's medium to which the sterile culture filtrate (boiled or unboiled) of a strain ofCl. welchiihad been added. The possibility of contamination of the cultures is emphasized.A final appraisal of the situation must be reserved until experiments with single cell isolates have been performed.