Table 1.
Antimicrobial resistance profiles and MIC distribution of Escherichia coli isolated from healthy broiler chickens in Korea.
| Antimicrobials | Distribution (%) of MICs (µg/mL) | MIC50 | MIC90 | MIC | Resistance | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.12 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | ≥512 | Range | (%) | |||
| Amoxicillin/clavulanic acid | 3.6 | 10.8 | 69.9 | 12.3 | 3.3 | 8 | 16 | 2–32 | 3.3 | ||||||||
| Ampicillin | 4.8 | 8.1 | 0.6 | 86.4 | 64 | 64 | 2–64 | 86.4 | |||||||||
| Cefepime | 87.3 | 1.8 | 2.4 | 0.6 | 3 | 3.6 | 1.2 | 0.25 | 1 | 0.25–16 | 1.2 | ||||||
| Cefoxitin | 7.2 | 48.2 | 35.2 | 5.7 | 3.6 | 1 | 4 | 1–32 | 3.6 | ||||||||
| Ceftazidime | 89.5 | 1.5 | 2.4 | 3 | 3.6 | 1 | 2 | 1–32 | 3.6 | ||||||||
| Ceftiofur | 75 | 10.5 | 0.3 | 14.2 | 0.5 | 8 | 0.5–8 | 13.9 | |||||||||
| Chloramphenicol | 0.3 | 12.7 | 18.4 | 1.5 | 2.1 | 65.1 | 64 | 64 | 2–64 | 67.2 | |||||||
| Ciprofloxacin | 1.8 | 11.7 | 4.8 | 1.5 | 1.8 | 2.7 | 43.7 | 31.9 | 8 | 16 | 0.12–16 | 78.3 | |||||
| Colistin | 99.4 | 0.6 | 2 | 2 | 2–8 | 0.6 | |||||||||||
| Gentamicin | 70.2 | 3.9 | 0.3 | 2.4 | 3 | 20.2 | 1 | 64 | 1–64 | 25.6 | |||||||
| Meropenem | 100 | 0.25 | 0.25 | 0.25–0.25 | 0 | ||||||||||||
| Nalidixic Acid | 2.1 | 1.8 | 2.1 | 1.5 | 0.6 | 1.5 | 90.4 | 128 | 128 | 2–128 | 92.5 | ||||||
| Streptomycin | 38.3 | 5.4 | 7.5 | 48.8 | 64 | 128 | 16–128 | 61.7 | |||||||||
| Sulfisoxazole | 29.8 | 2.1 | 68.1 | 512 | 512 | 16–512 | 68.1 | ||||||||||
| Tetracycline | 28.3 | 14.8 | 22.6 | 34.3 | 64 | 128 | 2–128 | 71.7 | |||||||||
| Trimethoprim/ | 33.4 | 9.3 | 4.8 | 2.4 | 0.3 | 49.7 | 1 | 4 | 0.12–4 | 49.7 | |||||||
| sulfamethoxazole | |||||||||||||||||
The dilution ranges tested are those contained in the white area. The breakpoints of tested antimicrobial agents are indicated by vertical lines. MIC50 and MIC90 are the concentrations at which 50% and 90% of the isolates were inhibited, respectively.