Factors Affecting the Germination of Spores of Clostridium botulinum Type E

Abstract

Germination of spores of Clostridium botulinum type E under varying conditions of Eh, pH, temperature, activation, and nutrition was studied. Germination in a complex medium consisting of thiotone, glucose and bicarbonate occurred at any level of initial Eh, regardless of the poising procedures employed. On the other hand, postgerminative development was affected by the initial Eh in the germination medium. Under an anaerobic condition, germination, outgrowth and division of cells were characterized by a peculiar profile of an Eh-time curve. The optimal conditions for germination of unheated spores in the complex medium were incubation at 37C and pH 6.6. The rate of germination increased with ageing time, the maximum rate being attained after storing an aqueous suspension of spores at 4 C for 20 days. The optimal heat activation was indicated when subjecting spores to heat-shock at 60 C for 10 min. Germination in a casamino acids medium was markedly stimulated by a supplementation of lactate. The minimum requirements of compounds needed for the germination of spores of C, botulinuin type E were L-alanine, glucose, lactate, and bicarbonate (CO₂). Germination occurred only in the following combinations of these compounds: r-alanine+glucose+lactate, L-alanine+glucose+bicarbonate, or L-alanine+lactate+bicarbonate.