TABLE 3.

Determination of interpretive error rates associated with NCCLS MIC and zone diameter breakpoints with isolates included in this study^a

Quinolone	MIC breakpoints (μg/ml)			Zone breakpoints (mm)			Error rates (no. [%])
	S	I	R	R	I	S	VM	M	Minor
Ofloxacin	≤2	4	≥8	≤12	13–15	≥16	0	0	6 (3.7)
Levofloxacin	≤2	4	≥8	≤13	14–16	≥17	0	0	2 (1.2)
Sparfloxacin	≤0.5	1	≥2	≤15	16–18	≥19	3 (8.6)	0	4 (2.5)
Grepafloxacin	≤0.5	1	≥2	≤15	16–18	≥19	0	0	3 (1.9)
Trovafloxacin	≤1	2	≥4	≤15	16–18	≥19	0	0	8 (5.0)

^aAbbreviations: S, susceptible; I, intermediate; R, resistant; VM, very major error; M, major error; Minor, minor error.