Table 1.
Susceptibility rates of S. pneumoniae isolate for six antimicrobial agents (n = 113)
| Antibiotics | MIC50 (μg/mL) | MIC90 (μg/mL) | MIC range (μg/mL) | MIC interpretive criteria (μg/mL) | Antimicrobial susceptibility | ||||
|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||
| S | I | R | S n (%) | I n (%) | R n (%) | ||||
| Penicillin parenteral (nonmeningitis) | 0.032 | 1 | 0.012–> 32 | ≤ 2 | 4 | ≥ 8 | 110 (97.3) | 2 (1.8) | 1 (0.9) |
| Penicillin parenteral (meningitis) | 0.032 | 1 | 0.012–> 32 | ≤ 0.06 | - | ≥ 0.12 | 88 (77.9) | 0 (0.0) | 25 (22.1) |
| Penicillin (oral) | 0.032 | 1 | 0.012–> 32 | ≤ 0.06 | 0.12–1 | ≥ 2 | 88 (77.9) | 17 (15.0) | 8 (7.1) |
| Erythromycin | 0.125 | 32 | 0.03–> 256 | ≤ 0.25 | 0.5 | ≥ 1 | 83 (73.5) | 0 (0.0) | 30 (26.5) |
| Azithromycin | 1 | 96 | 0.10–> 256 | ≤ 0.5 | 1 | ≥ 2 | 22 (19.5) | 57 (50.4) | 34 (30.1) |
| Amoxicillin-clavulanic acid | 0.03 | 1 | 0.015–8 | ≤ 2/1 | 4/2 | ≥ 8/4 | 110 (97.3) | 0 (0.0) | 3 (2.7) |
| Trimethoprim-sulfamethoxazole | 0.25 | > 32 | 0.064–> 32 | ≥ 0.5/9.5 | 1/19–2/38 | ≥ 4/76 | 77 (68.1) | 16 (14.2) | 20 (17.7) |
| Vancomycin | 0.5 | 0.5 | 0.12–1 | ≤ 1 | - | - | 113 (100.0) | 0 (0.0) | 0 (0.0) |
Notes: MIC50/90 = MIC at which 50% or 90% of the isolates are inhibited; S = susceptible; I = intermediate; R= resistant