Minimum Inhibitory Concentrations
(mcg/mL)

Disk Diffusion
(zone diameter in mm)

Pathogen

S

I

R

S

I

R

Enterobacteralesa

≤ 0.25

0.5

≥ 1.0

≥ 19

16-18

≤ 15

S = susceptible; I = intermediate; R = resistant

a Clinical efficacy was shown for E. coli, K. pneumoniae, and P. mirabilis.