Evidence is provided that the enterotoxin of Bacillus cereus variously described in the literature as diarrheagenic toxin, diarrheal agent, fluid accumulation factor, vascular permeability factor, dermonecrotic toxin,...
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Evidence is provided that the enterotoxin of Bacillus cereus variously described in the literature as diarrheagenic toxin, diarrheal agent, fluid accumulation factor, vascular permeability factor, dermonecrotic toxin, and intestinonecrotic toxin is a single relatively unstable protein of molecular weight approximately 50,000 and isoelectric point of the order of 4.9. It is presumed to be the enterotoxin responsible for the diarrheal-type B. cereus food poisoning syndrome and it may also be the pyogenic and pyrogenic factor in nongastrointestinal B. cereus infections of man and animals. The enterotoxin is a vegetative growth metabolite produced to one degree or another by almost all B. cereus strains and is readily separated from phospholipase and heat-labile cereolysin but less readily differentiated from a heat-stable hemolysin. It is lethal to mice but may also be separable from another mouse lethal factor by electrofocusing. The emetic toxin responsible for the vomiting-type B. cereus food poisoning syndrome is clearly distinguishable from the diarrheal and other toxic factors and appears to be a highly stable compound of molecular size <5000.
Monoclonal antibodies (MAbs) raised against Escherichia coli O6:H16 were screened against: 15 strains of E. coli and 19 non-E. coli bacteria. A MAb-luminescence assay using MAb-5.8, which shows no cross-reactions with...
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Monoclonal antibodies (MAbs) raised against Escherichia coli O6:H16 were screened against: 15 strains of E. coli and 19 non-E. coli bacteria. A MAb-luminescence assay using MAb-5.8, which shows no cross-reactions with non-E, coli bacteria, and a photon-counting television camera were developed for rapid enumeration of E. coli O16:H16 in water. The membrane filter that retained bacteria was boiled for 5 min in a buffer and incubated with biotinylated MAb5.8. Alter incubation with streptavidin-peroxidase conjugate, it was reacted with luminol-based reaction mixture. Luminous image and light intensity of the filter was recorded with a Biocell Counter. Levels of E. coli O6 higher than 7 x 10(3) CFU were detected by the MAb-luminescence assay when E. coli O6 was spotted onto the membrane filter. The sample that contained E, coli O6:H16 was filtered through a membrane filter, and the filter that retained bacteria was incubated on a filter paper soaked with nutrient: broth supplemented with 0.5% NaCl at 37'% for 6 h. The number of light emission points on the filter correlated well with initial E. coli O6:H16 counts within the range of 1 to 3 x 10(2) CFU. The correlation coefficient was 0.89.
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