TABLE 1.
Agent | MIC breakpoint (μg/ml) |
Disk diffusion breakpoint (mm) |
||||||
---|---|---|---|---|---|---|---|---|
S | MHTb | I | R | S | MHTb | I | R | |
IPM | ≤1 | 2-4 | 8 | ≥16 | ≥16 | NA | 14-15 | ≤13 |
MEM | ≤1 | 2-4 | 8 | ≥16 | ≥22 | 16-21 | 14-15 | ≤13 |
ERT | ≤1 | 2 | 4 | ≥8 | ≥22 | 19-21 | 16-18 | ≤15 |
DORc | ≤0.5 | NA | NA | NA | ≥23 | NA | NA | NA |
See references 5 and 6. S, susceptible; I, intermediate; R, resistant; MHT, modified Hodge test; NA, not applicable.
MHT is required to detect carbapenemase production. If MHT is positive, report MICs with no interpretation and with the following comment. “This isolate demonstrates carbapenemase production. The clinical efficacy of the carbapenems has not been established for treating infections caused by Enterobacteriaceae that test carbapenem susceptible but demonstrate carbapenemase production in vitro.” If MHT is negative, report carbapenems as susceptible (5, 6).
Food and Drug Administration criteria are given for DOR.