TABLE 5.
Characteristics of the diarrheagenic toxin produced by Clostridium perfringens isolated from four outbreaks
| Characteristic | Resultf by test and outbreak/strain (no. of strains examined) |
||||||
|---|---|---|---|---|---|---|---|
| Rabbit ileal loop test (FA)a for outbreak 1 (3) | Cytotoxicity (Vero cells) |
||||||
| Outbreak 1 (5) | Outbreak 2 (5) | Outbreak 3 (5) | Outbreak 4 (5) | CPE-positiveb strains (10) | CPE-negativec strains (10) | ||
| Crude toxin | + (1.3–2.0) | + | + | + | + | + | − |
| Mol wt | |||||||
| <30,000 | − | − | − | − | − | − | − |
| 30,000–50,000 | − | − | − | − | − | + | − |
| 50,000–100,000 | + (1.3–1.6) | +d | +d | +d | +d | − | − |
| >100,000 | − | − | − | − | − | − | − |
| Treatment with: | |||||||
| Heating at: | |||||||
| 60°C for 5 min | − | − | − | − | − | − | − |
| 60°C for 10 min | − | − | − | − | − | − | − |
| 100°C for 10 min | − | − | − | − | − | − | − |
| Acid (pH 4.0) | ± (0–0.6) | NT | NT | NT | NT | NT | NT |
| Alkali (pH 11.0) | − | NT | NT | NT | NT | NT | NT |
| Trypsin | + (1.0–1.9) | NT | NT | NT | NT | NT | NT |
| Pronase | − | NT | NT | NT | NT | NT | NT |
| Neutralization with antitoxine | NT | + | + | + | + | − | NT |
a
FA, fluid accumulation ratio. The strains from outbreaks 2, 3, and 4 are all positive on the rabbit ileal loop tests. FA ratios of the strain from outbreaks 2, 3, and 4 are 1.2 to 1.8, 0.9 to 1.6, and 1.1 to 1.6, respectively.
b
CPE-producing C. perfringens.
c
Non-CPE-producing C. perfringens.
d
The morphological changes were different from the change by the known CPE-producing isolates.
e
Antitoxin against the crude toxin prepared from the isolate on outbreak 1.
f
NT, not tested; +, positive; −, negative.