Table 2 Rates of resistance to various antibacterials among Streptococcus pneumoniae isolates collected during Years 1–4 (2000–2004) of the PROTEKT US study
Antibacterial | Year 1 (n = 10,103) | Year 2 (n = 10,012) | Year 3 (n = 10,886) | Year 4 (n = 8,494) |
|---|---|---|---|---|
Penicillin | ||||
MIC50/MIC90 (μg/mL) | 0.06/4 | 0.06/2 | ≤ 0.03/2 | ≤ 0.03/2 |
MIC range (μg/mL) | 0.06–16 | 0.06–16 | ≤ 0.03–16 | ≤ 0.03–16 |
Resistant (% of isolates) | 26.3 | 21.2 | 20.2 | 16.5 |
Intermediate (% of isolates) | 12.5 | 14.2 | 15.3 | 20.0 |
Amoxicillin-clavulanate | ||||
MIC50/MIC90 (μg/mL) | ≤ 0.12/2 | ≤ 0.12/2 | ≤ 0.12/2 | ≤ 0.12/2 |
MIC range (μg/mL) | ≤ 0.12-≥ 8 | ≤ 0.12-≥ 8 | ≤ 0.12-≥ 8 | ≤ 0.12-≥ 8 |
Resistant (% of isolates) | 4.4 | 3.5 | 4.0 | 4.1 |
Cefuroxime axetil | ||||
MIC50/MIC90 (μg/mL) | ≤ 0.12/8 | ≤ 0.12/8 | 0.25/8 | 0.25/4 |
MIC range (μg/mL) | ≤ 0.12-≥ 16 | ≤ 0.12-≥ 16 | 0.25-≥ 16 | ≤ 0.12-≥ 16 |
Resistant (% of isolates) | 28.8 | 24.1 | 23.0 | 20.4 |
Erythromycin | ||||
MIC50/MIC90 (μg/mL) | 0.12/16 | ≤ 0.06/16 | 0.12/64 | ≤ 0.06/256 |
MIC range (μg/mL) | ≤ 0.06-≥ 256 | ≤ 0.06-≥ 256 | ≤ 0.06-≥ 256 | ≤ 0.06-≥ 256 |
Resistant (% of isolates) | 31.0 | 27.9 | 29.2 | 29.1 |
Clarithromycin | ||||
MIC50/MIC90 (μg/mL) | 0.06/16 | ≤ 0.03/16 | ≤ 0.03/32 | ≤ 0.03/128 |
MIC range (μg/mL) | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 |
Resistant (% of isolates) | 30.7 | 27.5 | 28.7 | 28.9 |
Azithromycin | ||||
MIC50/MIC90 (μg/mL) | 0.12/32 | 0.12/32 | 0.12/≥ 256 | 0.12/256 |
MIC range (μg/mL) | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 | ≤ 0.03-≥ 256 |
Resistant (% of isolates) | 31.0 | 27.7 | 28.9 | 28.9 |
Telithromycin | ||||
MIC50/MIC90 (μg/mL) | ≤ 0.015/0.5 | ≤ 0.015/0.25 | ≤ 0.015/0.5 | ≤ 0.015/0.5 |
MIC range (μg/mL) | ≤ 0.015–8 | ≤ 0.015–4 | ≤ 0.015–4 | ≤ 0.015-≥ 4 |
Resistant (% of isolates) | 0.04 | 0.02 | 0.01 | 0.01 |
Levofloxacin | ||||
MIC50/MIC90 (μg/mL) | 1/1 | 1/1 | 1/1 | 1/1 |
MIC range (μg/mL) | ≤ 0.12–128 | ≤ 0.12-≥ 256 | ≤ 0.12–128 | ≤ 0.12-≥ 256 |
Resistant (% of isolates) | 0.8 | 1.1 | 0.8 | 1.0 |
Tetracycline | ||||
MIC50/MIC90 (μg/mL) | 0.25/≥ 8 | 0.25/≥ 8 | 0.25/≥ 8 | 0.25/≥ 8 |
MIC range (μg/mL) | ≤ 0.06-≥ 8 | ≤ 0.06-≥ 8 | ≤ 0.06-≥ 8 | ≤ 0.06-≥ 8 |
Resistant (% of isolates) | 15.9 | 14.9 | 14.8 | 14.6 |
Trimethoprim-sulfamethoxazole | ||||
MIC50/MIC90 (μg/mL) | ≤ 0.25/≥ 8 | ≤ 0.25/≥ 8 | ≤ 0.25/≥ 8 | ≤ 0.25/≥ 8 |
MIC range (μg/mL) | ≤ 0.25-≥ 8 | ≤ 0.25-≥ 8 | ≤ 0.25-≥ 8 | ≤ 0.25≥ 8 |
Resistant (% of isolates) | 33.9 | 28.2 | 26.8 | 24.1 |