The Destruction of Botulinum Toxin by Intestinal Bacteria.

Abstract

In our studies of the destruction of toxins by bacteria a number of interesting, and perhaps important, observations have been made. Among these the destruction of the toxin of Clostridium botulinum by certain intestinal types of bacteria may be worthy of particular note.

Several investigators have shown that if large numbers of detoxified botulinum spores are fed to experimental animals death from botulism will ensue, indicating that, under some conditions, the organisms can grow and produce their toxin in the intestinal tract. Since it is well known that the organisms of botulism are frequently ingested with such foods as raw vegetables, fruits and milk, the question naturally arises as to why the disease is not commonly transmitted in this way. It may also be questioned whether some of the so-called autointoxications are in fact incipient botulism arising from the limited growth of these organisms in the intestinal tract, with the production of sublethal quantities of toxin.

It occurred to us that the probable explanation was to be found in the action of the intestinal bacteria upon the toxins which might be formed in the alimentary tract. In Table I are given data which

indicate the destruction of botulinum toxin by Bact. coli, Bact. communior, Bact. aerogenes and Proteus vulgaris. In these experiments botulinum toxin (A type) was added to beef infusion broth so that the resulting medium contained approximately 100 m.l.d per cc. This toxin-broth mixture was inoculated with the different test organisms and allowed to incubate at 20° C. for two weeks. Uninoculated tubes of the toxin-broth mixture were of course incubated at the same temperature over the same period of time and subjected to the same filtering process in order to serve as controls. The unit amounts of toxin given in Table I are in terms of approximate m.l.d. values as determined on the control tubes after incubation.