Possible Origin of the High Incidence ofClostridium botulinumType E in an Inland Bay (Green Bay of Lake Michigan)

Abstract

Bottom and shoreline sediments of Green Bay, northern Lake Michigan, and rivers of the Green Bay drainage basin, as well as soils of the surrounding land mass, were examined for Clostridiuim botulinum type E. Detection was based on identification of type E toxin in enrichment cultures and was influenced by many factors. Testing smaller amounts of sample in multiple cultures was more productive than examining large inocula in fewer cultures. Incubation at 30 C was unsatisfactory, but 14 days at 20 C or 7 days at 25 C gave good results. Mild heating (60 C for 30 min) of specimens reduced the incidence of positive findings. Freezing enrichment cultures prior to testing for toxicity eliminated many nonbotulinal toxic substances that killed mice. A control culture inoculated with type E spores was employed to show whether a specimen contained factors which could mask the presence of type E. Samples from 708 stations were tested in 2,446 cultures. Type E was found in nearly all underwater specimens of Green Bay and northern Lake Michigan but was present less frequently in samples taken along their shores. The incidence was still lower in the rivers emptying into Green Bay with the organism being rare on the shores of these rivers and in the soils of the land mass proper. Samples from the upper reaches of the rivers practically never contained type E. Runoff could deposit type E spores in Green Bay, but this is not considered to be the major factor in the high incidence of the organism. Multiplication in the bay itself is indicated.

Intraintestinal toxin in infant mice challenged intragastrically with Clostridium botulinum spores

“…They were thawed the next morning without disturbance, and the top portion of the fluid column was used for the toxin test. This method has successfully identified botulinum toxin of low LD5o levels in specimens having interfering amounts of "nonspecific" (2,14). Confirmatory tests used types A and B botulinum antitoxins and normal rabbit serum.…”

Observations on the distribution and ecology of Clostridium botulinum type E in Alaska

“…Our findings, although based upon a small number of specimens, confirm earlier reports of the isolation of C. botulinum from salmon taken along the Pacific Coast (12). The recovery of botulinum spores in the intestine has been correlated with the presence of ingested food (2,3,23), whereas their presence in the gills was associated with the proximity of the fish to land masses and river outlets, and to the ability of the gills to filter and retain spores (6). Contaminated sediments are likely sources of water-borne spores; consequently, any increase in the populations of C. botulinum in sediments would result in a proportionate increase in the numbers of fish contaminated with C. botulinum.…”

Inhibition of Clostridium botulinum by Strains of Clostridium perfringens Isolated from Soil

“…It is apparent that soil does contain organisms that can interfere with the demonstration of C. botulinum types A, B, and F just as has been reported for type E (2,8). Detection of such inhibitor organisms can be accomplished by the method of Bott et al 2, i.e., by inoculating cultures of soil in which C. botulinum could not be demonstrated with spores of a toxigenic strain of this organism, incubating, and testing for toxin.…”

“…The demonstration of Clostridium botulinum in soil, sediment, or food is usually carried out by inoculating samples of the material under investigation into tubes of suitable media, incubating anaerobically, and testing the culture fluid for botulinum toxin which is identified by neutralization with type-specific antitoxin. Cooked meat medium is best for this purpose; Bott et al (2) found that the beef heart infusioncooked meat medium of Johannsen (7) usually gave about 10-fold higher toxin yields than did other media, including Trypticase-peptone-glucose, glucose-peptone-beef infusion, proteose peptone-Trypticase, fish infusion, reinforced clostridial medium, or brain-heart infusion.…”