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Table 1 Concentrations of antimicrobial agents and interpretative breakpoint or cut-off values.

From: Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

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
  1. S, susceptible; I, intermediate; R, resistant.
  2. a CLSI standard for agar dilution susceptibility testing[11].
  3. b quality control range developed by the manufacturer Sensititre®