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PubMed1979

Shigellosis and Escherichia coli diarrhea: relative importance of invasive and toxigenic mechanisms.

Shigellae and dysentery-like Escherichia coli must invade the epithelium of the colon to cause disease which can present as dysentery, diarrhea, or both. This paper addresses the possible role of a Shigella dysenteriae-like (Shiga-like) toxin in the pathogenesis of shigellosis and E. coli diarrheal diseases. The possibility for such a role is suggested by the following observations: 1) diarrhea, considered to be a result of secretion of water by the small bowel, is frequently observed in shigellosis, a large bowel disease. 2) Even though shigellae do not invade the jejunum of monkeys fed Shigella flexneri, jejunal secretion is seen in animals with diarrhea. 3) The Shiga toxin of S. dysenteriae has enterotoxic activity and other serotypes of shigellae produce Shiga-like toxins. 4) E. coli 015 RDEC-1 causes a diarrheal disease and frequently death in young rabbits. This organism neither produces E. coli enterotoxins nor is it invasive, but it may produce low levels of a Shiga-like toxin.

Animals↗
PubMed1979

Protective effect of active immunization with purified Escherichia coli heat-labile enterotoxin in rats.

The protective effect of active immunization by different routes with a purified preparation of the polymyxin-release form of Escherichia coli heat-labile toxin was evaluated in rats. Immunized animals were challenged by placing toxin into ligated ileal loops at dosages which produced either 50% or the maximum secretory response in unimmunized rats. Immunization exclusively by the parenteral route yielded significant protection. Rats were also protected when parenteral priming was followed by boosting given either directly into the duodenum or perorally 2 h after intragastric cimetidine, but not when the peroral boosts were given with bicarbonate. Immunization administered entirely by the peroral route with cimetidine yielded protection but only when the immunizing dosage was fivefold greater than that found effective in the parenteral-peroral approach. Rats immunized exclusively by the parenteral route and those boosted perorally with cimetidine were also tested, and found to be protected, against challenge with viable organisms of strains that produce either heat-labile toxin alone or both heat-labile and heat-stable toxin, but they were not protected against a strain which produces just heat-stable toxin. Geometric mean serum antibody titers were increased by 16-fold or more over control values in those groups of rats in which protection was achieved, with the exception of those immunized exclusively by the peroral route. These observations demonstrate that (i) active immunization with purified E. coli heat-labile toxin results in significant protection against both this toxin as well as viable organisms which produce it, but not against viable strains which produce heat-stable toxin only, and (ii) concomitant ablation of gastric secretion by the use of cimetidine renders the peroral route of immunization effective. They suggest that prophylactic immunization against diarrheal disease caused by heat-labile toxin-producing strains of E. coli may be feasible in humans.

Animals↗
PubMed1964

TAXONOMY OF CLOSTRIDIUM BIFERMENTANS AND CLOSTRIDIUM SORDELLII. I. THEIR TOXIGENICITY, UREASE ACTIVITY, AND SPORULATING POTENCY.

Nishida, S. (Kanazawa University, Kanazawa, Japan), K. Tamai, and T. Yamagishi. Taxonomy of Clostridium bifermentans and Clostridium sordellii. I. Their toxigenicity, urease activity, and sporulating potency. J. Bacteriol. 88:1641-1646. 1964.-Strains with properties similar to those of Clostridium bifermentans were usually obtained by selecting heat-resistant substrains of C. sordellii 1734. Heat-resistant substrains obtained from seven other strains were also found to be nontoxic. Some of these heat-resistant substrains produced urease, but others did not. Substrains of typical cultures of C. sordellii thus can yield either substrains resembling nonpathogenic strains of C. sordellii culturally, or substrains resembling C. bifermentans. The sporulating potency of pathogenic and nonpathogenic strains of C. sordellii and strains of C. bifermentans proved to be significantly distinct. The sporulating potency of C. bifermentans was high, that of pathogenic strains of C. sordellii was low, and that of nonpathogenic strains of C. sordellii was intermediate between the other two.

Antitoxins↗
PubMed1975

On the question of permeability of the blood-brain barrier to botulinum toxin.

The clinical symptoms of botulinum intoxication suggest that besides the involvement of the peripheral nervous system, the central nervous system is also affected. Studies were undertaken to determine whether pure toxin of Clostridium botulinum type A could be demonstrated in the brains of poisoned mice. With the aid of autoradiography of the toxin marked with 125-I and indirect fluorescent labeling it was possible to show the presence of the toxin in the parenchyma of the brain.

Animals↗