Table 1 Concentrations of antimicrobial agents and interpretative breakpoint or cut-off values.
Antimicrobial agents | Concentration ranges used in the three media (mg/L) | Quality control rangea for E. coli ATCC 25922 (mg/L) | CLSI clinical breakpoint (mg/L) | EUCAST epidemiological cut-offs (mg/L) | ||
|---|---|---|---|---|---|---|
S | I | R | R | |||
Ampicillin | 0.25–128 | 2–8 | ≤ 8 | 16 | ≥32 | > 8 |
Cephalothin | 2–64 | 4–16 | ≤ 8 | 16 | ≥32 | > 32 |
Chloramphenicol | 1–128 | 2–8 | ≤ 8 | 16 | ≥32 | > 16 |
Gentamycin | 0.5–64 | 0.25–1 | ≤ 2 | 4 | ≥8 | > 2 |
Streptomycin | 2–128 | 4–16b | ≤ 8 | 16 | ≥32 | > 16 |
Cefotaxime | 0.06–128 | 0.03–0.12 | ≤ 8 | 16–32 | ≥64 | > 0.25 |
Sulfamethoxazole | 8–1024 | 8–32 | ≤ 256 | _ | ≥ 512 | > 256 |
Oxytetracycline | 0.25–256 | 0.5–2 | ≤ 4 | 8 | ≥16 | > 8 |