The influence of
Cl. sporogenes on the toxin production and diminution of
Cl. botulinum has not been fully investigated. The purpose of this paper is to demonstrate; (a) the activation of
Cl. botulinum by
Cl. sporogenes and (b) the effect of
Cl. sporogenes on
Cl. botulinum toxins. For this purpose, the experiments were carried out by combining
Cl. sporogenes and
Cl. botulinum in nutrient broth. Seven strains of
Cl. botulinum and four strains of
Cl. sporogenes were studied. The former strains were type A (AK-38); two type B (Lamanna and QC); type C (Stockholm); type D (1873); type E (Iwanai); type F (OSU) while the latter strains GO; NIH; IMS.
The media used was T. Y. G. medium consisting of trypticase (BBL) 3%, yeast extract (Difco) 2%, glucose 0.5% and Na-thioglycollate 0.05%, pH 6.8; and all cultures were incubated at 37°C. Toxicity tests were performed by intraperitoneal injection into white mice having the weight of about 20g. The animals were observed for 5 days and 50% lehtal dose was calculated by Behrens-Kaerber method.
In the combined culture of each type of
Cl. botulinum with
Cl. sporogenes the following results were obtained:
1. The effects of
Cl. sporogenes on
Cl. botulinum type A, B, E and F toxins.
(1) after incubation for one hour at 37°C.
a. In general, the degree of virulence of
Cl. botulinum type A, B, E and F toxins was increased by the presence of
Cl. sporogenes, and was activitated to a certain extent by treatment with trypsin.
b. Activation was most marked on
Cl. botulinum type E toxin.
(2) after incubation for twenty hours at 37°C.
a. The toxicity of all types of
Cl. botulinum decreased.
b.
Cl. botulinum type E toxin was markedly inactivated.
2. However, no definite effects could be observed on virulence of
Cl. botulinum type C and D by the presence of
Cl. sporogenes, nor inactiviated by treatment with trypsin.
When
Cl. botulinum is isolated from soil or suspected foodstuffs, we often make a negative diagnosis, when the tests show the result of non-toxicity during the first stage of incubation. Sampling of soil without
Cl. sporogenes for the detection of
Cl. botulinum is difficult in the early stage of isolation, but it is recommended to inspect if
Cl. sporogenes is in the suspected samples.
Cl. botulinum toxins will be inactivated during the incubation period.
From the results of some investigations, the author should like to point out that further investigation should be made as to the effects of coexistent bacteria in the suspected samples.
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