Preliminary interpretive susceptibility testing criteria for FK-037 with 30-microgram disks.

FK-037, a new parenteral cephalosporin, was tested against 483 organisms from clinical infections to establish preliminary susceptibility testing criteria with 30-micrograms disks. The proposed breakpoint zone diameters were > or = 17 mm (MIC correlate, < or = 8 micrograms/ml) for the susceptible category and < or = 13 mm (MIC correlate, > or = 32 micrograms/ml) for the resistant category. These interpretive guidelines produced no very major (false-susceptible) errors, 2.9% major (false-resistant) errors, and 6.2% minor errors for a total absolute agreement between methods of 90.9%.