Distinction between Clostridium botulinum type A strains associated with food-borne botulism and those with infant botulism in Japan in intraintestinal toxin production in infant mice and some other properties

In Bordetella pertussis virulence-associated genes, including adenylate cyclase toxin (Cya), are coordinately regulated in response to environmental signals by proteins coded by the bvg-locus. We have constructed cya-lac fusions in Escherichia coli and have shown that the cya operon is not expressed in E. coli, neither is it activated by bvg, when introduced in trans. The cya-lac fusion is fully active when returned to B. pertussis by homologous recombination and responds to bvg-dependent activation and environmental regulation. These results indicate that in B. pertussis the activation of the cya operon by bvg is indirect.     

Attempts to quantity Clostridium botulinum type A toxin and antitoxin in serum of two cases of infant botulism in Japan

Serum samples taken from two infant botulism cases during hospitalization were titrated for botulinum toxin by both the intraperitoneal (ip) injection method and the score method in mice. By the ip method, in which death is the only parameter, such low levels of toxin as lower than 4 ip LD50/ml may not be titrated even though the surviving mice show abdominal palsy. By the score method based on the degree of abdominal palsy, such low levels of toxin as 1.1 and 0.8 ip LD50/ml were detected in specimens of one of the patient's serum. No antitoxin was demonstrated in either case of infant botulism by applying the score method. It is not known whether spontaneous recovery from infant botulism is due to the antitoxin production.     

Purification and some properties of Clostridium botulinum type AB toxin

Abstract The progenitor toxin of Clostridium botulinum type AB was purified; both large-sized (L) and medium-sized (M) toxins were found. The toxicity of M toxin increased by about 10-fold upon trypsinization; the increase was due mostly to type B toxin and a little to type A toxin. M toxin appeared to consist of one molecule each of toxic and nontoxic components. The activated toxic component was made up of four fragments, A-H- and L-chains and B-H- and L-chains. AB toxin may be a mixture of A and B toxins.     

Persistence of Clostridium botulinum type C toxin in blow fly (Calliphoridae) larvae as a possible cause of avian botulism in spring

Diverse samples were examined at a site of water-bird mortality, caused by Clostridium botulinum type C toxin in southern Moravia (Czechoslovakia). The toxin was detected in high concentrations in mute swan (Cygnus olor) carcasses (less than or equal to 1 x 10(6) LD50/g) as well as in necrophagous larvae and pupae of the blow flies Lucilia sericata and Calliphora vomitoria (less than or equal to 1 x 10(5) LD50/g) collected from them. It was detected in lower concentrations (less than or equal to 1 x 10(3) LD50/g) in other invertebrates (ptychopterid fly larvae, leeches, sow-bugs) associated with these carcasses, and occasionally in water samples (8 LD50/ml) close to the carrion. The toxin was not detected in the samples of water, mud or invertebrates collected at a distance greater than or equal to 5 m from the carcasses. The toxin-bearing larvae of L. sericata and C. vomitoria, containing 80,000 LD50/g of type C toxin, were exposed in the mud at the study site for 131 days from November to March. Although the toxin activity decreased 25-fold and 40-fold in the two samples of maggots exposed during this period, it remained very high (less than or equal to 3,200 LD50/g). Birds ingesting a relatively low number of these toxic larvae (or pupae) in the spring could receive a lethal dose of the toxin.     

Enzyme-linked immunosorbent assay for detection of Clostridium botulinum toxin type A.

The enzyme linked immunosorbent assay using the so-called "double-sandwich technique" has been applied to determine botulinum toxin type A. By this assay, 50-100 mouse ip LD50 of toxin type A can be detected. No cross-reaction occurs with botulinum toxins of other types tested. In all probability this is due to the high specificity of the antiserum prepared against the toxic component of type A toxin.     

Production of toxin by Clostridium botulinum type A strains cured by plasmids

Twelve strains of Clostridium botulinum type A and seven strains of Clostridium sporogenes were screened for plasmids by agarose gel electrophoresis of cleared lysates of cells from 5 ml of mid-log-phase culture. Nine type A strains had one or more plasmids of 4.3, 6.8, or 36 megadaltons (MDa); several strains showed a large plasmid of 61 MDa, but it was not consistently recovered. Four C. sporogenes strains had one or more plasmids of 4.3, 5.6 or 36 MDa. Isolates obtained from cultures of plasmid-containing C. botulinum type A strains grown in ionic detergent broth and from spontaneously arising variants were screened both for toxin production and for plasmid content. Toxigenicity of C. botulinum could not be correlated with the presence of any one plasmid.