Disk diffusion susceptibility test interpretive criteria for GR69153, a new catechol-substituted cephalosporin.

GR69153 disk diffusion tests with 10- and 30-micrograms disks were evaluated against 383 rapidly growing aerobic pathogens. Very high absolute agreement (96.1 to 98.1%) was observed between the MICs and disk zone diameters, and no false-susceptible results were encountered with the proposed criteria. The 30-micrograms GR69153 disk with a susceptible-zone diameter of greater than or equal to 17 mm (MIC correlate, less than or equal to 8 micrograms/ml) and a resistant-zone diameter of less than or equal to 13 mm (MIC correlate, greater than 16 micrograms/ml) is recommended. GR69153 had a spectrum of activity slightly wider than that of ceftazidime against the species tested.