TABLE 1.
Susceptibility to selected antimicrobials of penicillin-nonsusceptible S. pneumoniae determined by NCCLS interpretive standards
| Antibiotic | MIC breakpoints (μg/ml)a | Susceptibility based on MIC (%)
|
||
|---|---|---|---|---|
| Susceptible | Intermediate | Resistant | ||
| Azithromycin | S ≤ 0.5; I = 1; R ≥ 2 | 96 (28.8) | 0 (0) | 237 (71.2) |
| Erythromycin | S ≤ 0.25; I = 5; R ≥ 1 | 96 (28.8) | 5 (1.5) | 232 (69.7) |
| Amoxicillin | S ≤ 2; I = 4; R ≥ 8 | 266 (79.9) | 64 (19.2) | 3 (0.9) |
| Ceftriaxone | S ≤ 1; I = 2; R ≥ 4 | 299 (89.8) | 29 (8.7) | 5 (1.5) |
| Cefprozil | S ≤ 2; I = 4; R ≥ 8 | 19 (5.7) | 78 (23.4) | 236 (70.9) |
| Cefdinir | S ≤ 0.5; I = 1; R ≥ 2 | 5 (1.5) | 1 (0.3) | 327 (98.2) |
| Levofloxacin | S ≤ 2; I = 4; R ≥ 8 | 332 (99.7) | 1 (0.3) | 0 (0) |
| TMP/SMZb | S ≤ 0.5; I = 1-2; R ≥ 4 | 5 (1.5) | 17 (5.1) | 311 (93.4) |
a
Per NCCLS.
b
TMP/SMZ, trimethoprim-sulfamethoxazole (ratio 1:20); results for the trimethoprim component are reported.