TABLE 2.

Comparison of MIC ranges, MIC₅₀s, MIC₉₀s, and percentage of isolates susceptible/intermediate to imipenem, meropenem, and ertapenem for RGM isolates by broth microdilution

Complex or species and drug	Intermediate breakpoint (μg/ml)	No. of isolates tested	MIC (μg/ml)			% susceptible/intermediate
			Range	50%	90%
M. fortuitum
Imipenem	8–16	38	2–8	4	8	100
Meropenem	8–16	38	4–16	8	16	100
Ertapenem	4a	38	8–32	16	>32	0
M. porcinum
Imipenem	8–16	10	2–16	4	8	100
Meropenem	8–16	9	2–16	16	16	100
Ertapenem	4a	9	1–16	8	16	11
M. abscessus subsp. abscessus
Imipenem	8–16	67	4–>16	>16	>16	66
Meropenem	8–16	67	8–>16	>16	>16	12
Ertapenem	4a	67	8–>32	>32	>32	0
M. massiliense
Imipenem	8–16	11	8–>16	>16	>16	73
Meropenem	8–16	11	≥16	>16	>16	9
Ertapenem	4a	11	≥32	>32	>32	0
M. chelonae
Imipenem	8–16	21	8–16	16	≥16	52
Meropenem	8–16	21	>16–>32	>16	>16	0
Ertapenem	4a	21	>16–>32	>32	>32	0
M. mucogenicum/M. phocaicum group
Imipenem	8–16	16	≤0.5–4	2	4	100
Meropenem	8–16	16	≤0.5–8	4	8	100
Ertapenem	4a	16	2–4	2	4	100

^aBased on the CLSI breakpoint for bacteria.