TABLE 3.
| Drug and parameter | μg/ml
|
||
|---|---|---|---|
| S. intermedius | S. constellatus | S. anginosus | |
| Penicillin | |||
| MBC50 | 0.06 | 0.12 | 0.06 |
| MBC90 | 0.12 | 0.25 | 0.25 |
| Mean | 0.06 | 0.12 | 0.07 |
| Ampicillin | |||
| MBC50 | 0.25 | 0.5 | 0.12 |
| MBC90 | 0.25 | 1.0 | 0.25 |
| Mean | 0.19 | 0.39 | 0.10 |
| Ceftriaxone | |||
| MBC50 | 0.12 | 0.25 | 0.12 |
| MBC90 | 0.25 | 0.5 | 1.0 |
| Mean | 0.12 | 0.30 | 0.24 |
| Clindamycin | |||
| MBC50 | 0.12 | 0.12 | 0.5 |
| MBC90 | 0.5 | 1.0 | 16 |
| Mean | 0.17 | 0.18 | 0.62 |
Differences in MBCs among the three species were significant (P < 0.05) (Kruskal-Wallis test).
MBC of penicillin for S. constellatus was greater than that for S. intermedius; MBC of ampicillin for S. constellatus was greater than those for S. intermedius and S. anginosus; MBC of ceftriaxone for S. constellatus was greater than that for S. intermedius; P < 0.05 for all comparisons (Mann-Whitney test); MBC of clindamycin for S. anginosus was greater than that for S. intermedius or S. constellatus (P < 0.05 for both comparisons) (Mann-Whitney test).