TABLE 4.
The spore formation and the cytotoxic effects of the isolates in each medium
| Culture medium | Cell type | Resultd by outbreak/strain (no. of strains examined) |
|||||
|---|---|---|---|---|---|---|---|
| Outbreak 1 (5) | Outbreak 2 (5) | Outbreak 3 (5) | Outbreak 4 (5) | CPE-positivea strains (10) | CPE-negativeb strains (10) | ||
| Modified DS medium | |||||||
| Spore forming | +++ | +++ | +++ | +++ | +∼++ | +∼++ | |
| Cytotoxic effects | Vero | +c | +c | +c | +c | + | − |
| Cytotoxic effects | L929 | + | + | + | + | − | − |
| Cooked meat broth | |||||||
| Spore forming | − | − | − | − | − | − | |
| Cytotoxic effects | Vero | − | − | − | − | − | − |
| Cytotoxic effects | L929 | − | − | − | − | − | − |
| TGCII broth | |||||||
| Spore forming | − | − | − | − | − | − | |
| Cytotoxic effects | Vero | − | − | − | − | − | − |
| Cytotoxic effects | L929 | − | − | − | − | − | − |
a
CPE-producing C. perfringens.
b
Non-CPE-producing C. perfringens.
c
Morphological changes were different from the change by the known enterotoxin-producing isolates.
d
+, positive; −, negative; +++, spore-forming rate approximating >20%; +~++, spore-forming rate approximating <20%.