Table 1. MICs and percentages of bacitracin resistance of C. perfringens isolates.
| Origin(a) | Number of isolates with a MIC (µg/ml) of | MIC 90 b and MIC 50 b (µg/ml) | |||||||||
| 0.75 | 1 | 2 | 3 | 4 | 6 | 8 | 12 | 16 | >256 | ||
| Turkey (81) | 0 | 0 | 12 | 16 | 10 | 11 | 3 | 7 | 3 | 19 | >256 and 6 |
| Chicken (18) | 2 | 1 | 5 | 1 | 1 | 1 | 1 | 1 | 0 | 5 | >256 and 3 |
a
Numbers of isolates; the three C. perfringens isolates of chicken origin associated with necrotic enteritis had MIC values of 3, 4 and 256 µg/ml; while the three type E isolates of turkey origin had MIC values of 4, 6 and 12 µg/ml.
b
Concentration where growth was inhibited in 50% and 90% of the isolates.
The vertical line indicates the high level bacitracin resistance breakpoint of >256 µg/ml.