TABLE 1.
In vitro activities of penicillin and erythromycin individually and in combination against S. pneumoniae strains of different serotypes and resistance profiles
| Serotype (isolate no.)a | MIC (μg/ml)
|
FICI | Interactive category | ||
|---|---|---|---|---|---|
| Penicillin | Erythromycin | Penicillin-erythromycin combination | |||
| Penicillin susceptible, erythromycin susceptible | |||||
| 1 (364.0344) | 0.016 | 0.125 | 0.016/0.125 | 2 | Indifference |
| 12 (005.0358) | 0.016 | 0.250 | 0.016/0.250 | 2 | Indifference |
| 12 (1014) | 0.016 | 0.062 | 0.016/0.125 | 3 | Indifference |
| Penicillin resistant, erythromycin susceptible | |||||
| 9 (0566) | 0.500 | 0.125 | 0.500/0.125 | 2 | Indifference |
| 9 (3848) | 0.250 | 0.125 | 0.250/0.125 | 2 | Indifference |
| 14 (039.0723) | 0.250 | 0.125 | 0.500/0.125 | 2 | Indifference |
| 19 (2660) | 0.125 | 0.250 | 0.125/0.250 | 2 | Indifference |
| 19 (4320) | 0.500 | 0.250 | 0.500/0.125 | 1.5 | Indifference |
| Penicillin susceptible, erythromycin resistant | |||||
| 7 (315.0353) | 0.016 | 8.000 | 0.016/8.0 | 2 | Indifference |
| 38 (0865) | 0.016 | 4.000 | 0.016/4.0 | 2 | Indifference |
| Penicillin resistant, erythromycin resistant | |||||
| 6 (4828) | 0.125 | 4.000 | 0.125/4.0 | 2 | Indifference |
a
Serotype was determined by Quellung procedures.