Epidemiologic cutoff values to separate wild-type from non-wild-type Campylobacter fetus to ciprofloxacin.

The aim of the present study was to propose epidemiologic cutoffs that could be used in routine practice to separate wild-type from non-wild-type Campylobacter fetus to ciprofloxacin. A total of 123 C. fetus isolates obtained from human samples were used for this purpose. Based on the determination of inhibition zone diameter, minimum inhibitory concentration, and sequencing of the quinolone resistance determining region in the gyraseA gene, for all tested isolates, the following cutoffs were proposed: ciprofloxacin-wild type if the inhibition zone diameter was ≥22 mm or the minimum inhibitory concentration was ≤0.5 mg/L.