Fluorescent-antibody reagents for the identification of Clostridium botulinum

Abstract

Fluorescent-antibody reagents were prepared against vegetative cells of representative strains of each physiological group and toxin type of Clostridium botulinum known to have caused botulism in humans. A fluorescent-antibody reagent was also prepared for C. botulinum type G, which has been isolated from autopsy specimens but which has not clearly been implicated in botulism. These fluorescent-antibody reagents were evaluated against 200 strains of C. botulinum and 64 strains of other clostridia. Each reagent reacted with at least a 2 + intensity with all of the strains in its same toxin type and physiological group. Ninety-seven percent of the strains gave at least a 3+ reaction with the homologous group or toxin type reagent. Some cross-reactions occurred with reagents against different toxin type strains within a physiological group; there was less cross-reaction between physiological groups and very little reactivity of C. botulinum reagents with nontoxigenic organisms. Absorption of cross-reacting antibodies was not successful. Certain reagents could be used for presumptive laboratory identification of C. botulinum strains causing botulism, especially in infants. The type G reagent provided a good means of identifying C. botulinum type G, which lacks the lipase marker and whose toxigenicity may be more difficult to demonstrate in mixed cultures. There was a serological relationship between C. botulinum type G and some strains of Clostridium subterminale. This relationship provided evidence of differences between strains of C. botulinum type G isolated in two different countries.

Multilocus enzyme electrophoresis of Clostridium argentinense (Clostridium botulinum toxin type G) and phenotypically similar asaccharolytic clostridia

“…DNA relatedness group 1 contains all strains of C. botulinum toxin type G as well as three nontoxigenic strains that had been incorrectly identified as C. subterminale (two strains) and C. hastiforme (one strain). These strains were previously shown to cross-react in serologic tests (3,4). The name Clostridium argentinense has been proposed to include both toxigenic and nontoxigenic strains in DNA relatedness group 1 (8).…”

Isolation of Clostridium botulinum type G from Swiss soil specimens by using sequential steps in an identification scheme

“…The results obtained with the ELISA and the electroblot procedures by Poxton (14) conclusively show that most strains of C. botllinium types A and proteolytic B (group I) share antigens with C. sporogenes, a nontoxigenic variant of C. botulinum, whereas types C and D (group III) share antigens with C. novyi. A type G (group IV) fluorescent-antibody reagent tested in a study by Glasby and Hatheway (8) successfully identified all seven strains of C. botulinum type G which were isolated from the two different locations but cross-reacted with two strains of C. subterminale. The relationship is similar to that of C. sporogenes of group I. Absorption of the type G fluorescentantibody conjugate with C. subterminale removed activity for the Swiss strains but not for the two Argentinian strains.…”

“…That its presence has never been established in any food poisoning outbreak or in any food may be due to a lack of suitable detection methods. The use of a fluorescent-antibody technique and an enzyme-linked immunosorbent assay (ELISA) to detect and identify this toxin type in fecal specimens and enrichment cultures has been described previously (8,11).…”

Selection and Development of Nontoxic Nonproteolytic Clostridium botulinum Surrogate Strains for Food Challenge Testing

“…The inclusion of antitoxin antibodies in the growth medium was shown to improve the detection of BoNT-producing strains by the formation of a precipitation zone around the colonies, but no data is available on the performance of these plates with complex samples containing background microbiota [ 33 , 34 ]. Finally, fluorescent antibodies against vegetative cell walls of C. botulinum have been used in culture, but this technique has never been adopted for use in solid media to determine C. botulinum cell counts [ 35 ].…”