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

MIC, minimum inhibitory concentration.

Jenkins et al. Annals of Clinical Microbiology and Antimicrobials 2008 7:1   doi:10.1186/1476-0711-7-1