Table 5.
MIC breakpoints according to CLSI in 2021 and MIC50; MIC90 of antibiotics for isolated Streptococcus pneumoniae.
| Antibiotics | MIC breakpoints according to CLSI in 2021 (mg/L) | MIC50 (mg/L) | MIC90 (mg/L) | ||
|---|---|---|---|---|---|
| S | I | R | |||
| Trimethoprim/sulfamethoxazole | ≤ 0.5/9.5 | 1/19–2/38 | ≥4/76 | 4/76 | 4/76 |
| Clindamycin | ≤ 0.25 | 0,5 | ≥1 | 1 | 1 |
| Erythromycin | ≤ 0.25 | 0,5 | ≥1 | 1 | 1 |
| Clarithromycin | ≤ 0.25 | 0,5 | ≥1 | 1 | 1 |
| Penicillin (non-meningitis) | ≤ 2 | 4 | ≥8 | 64 | 64 |
| Ceftriaxone (non-meningitis) | ≤ 1 | 2 | ≥4 | 2 | 6 |
| Chloramphenicol | ≤ 4 | – | ≥8 | 4 | 8 |
| Ciprofloxacin | NT | NT | NT | 1.5 | 12 |
| Levofloxacin | ≤ 2 | 4 | ≥8 | 0.75 | 8 |
| Vancomycin | ≤ 1 | – | – | 1 | 1 |
| Linezolid | ≤ 2 | – | – | 2 | 2 |
MIC, Minimal Inhibitory Concentration; MIC50, concentration at which 50% of bacterial strains were inhibited; MIC90, concentration at which 90% of bacterial strains were inhibited; CLSI, clinical and laboratory standards institute; S, susceptible; I, intermediate; R, resistant; NT, not tested.