Enzyme-linked immunosorbent assay for detection of Clostridium botulinum type A and type B toxins in stool samples of infants with botulism

An enzyme-linked immunosorbent assay (ELISA) for Clostridium botulinum type A and type B toxins was assessed for diagnostic accuracy in cases of infant botulism. This test was positive in all 22 cases confirmed by the conventional tests, which included the mouse lethality assay and stool culture. Stool specimens from five cases were positive by culture, but the mouse lethality bioassay was either negative or toxicity was judged nonspecific since it could not be neutralized by specific antitoxin. The positive ELISA results in these specimens suggested that this assay may be more reliable, in somes cases, than the mouse bioassay. Of the 21 fecal specimens from suspected foodborne cases, 2 contained botulinal toxin demonstrable by the mouse assay and the ELISA. With regard to specificity, 35 fecal specimens from infants and 19 from suspected foodborne cases which were negative in the bioassay for botulinal toxins A and B were also negative in the ELISA. Only two fecal specimens with negative bioassay gave positive ELISA readings, providing a specificity rate of 96%. These results suggest that the ELISA may serve as a useful screening test to detect C. botulinum toxin in clinical specimens.