Physiological studies on spore germination, with special reference to Clostridium botulinum; inhibition of germination by unsaturated C18 fatty acids
Foster, J.W.; Wynne, E.S.
Journal of Bacteriology 55(4): 495-501
ISSN/ISBN: 0021-9193 PMID: 18909075 Accession: 055002634
II. Oleic, linoleic, and linolenic acids have been shown to be strongly inhibitory to the germination of spores of six strains of Clostridium botulinum, linolenic being most effective; stearic acid was completely inactive. Spores of Clostridium perfringens and putrefactive anaerobe no. 3679 were less inhibited, whereas spores of Clostridium histolyticum and Clostridium chauvei were only slightly affected by oleate. Spores of four aerobic species were unaffected. Oleic acid in a concentration of 100 micro g per ml prevented germination of large spore inocula of C. botulinum over 40.5 months. Vegetative cells of C. botulinum are not inhibited by these acids. Oleate at 100 micro g per ml is not sporocidal itself, as killing was not observed in distilled water but only in a complete medium (brain heart). The degree of effectiveness of these C18 acids in suppressing germination was greatly different in two different lots of the same medium. The effect of inhibitory substances in nutritionally adequate media may cause more conflicting results in bacteriology than is now appreciated. Starch (0.1 per cent) can neutralize fatty acid type inhibitors and possibly other types.