Table 2.

Distribution and corresponding carbapenem MIC ranges for strains with different resistance determinants.

Carbapenem resistance mechanisms	No. of isolates	MIC range (mg/L)
		ETP	IMP	MEM
Carbapenemase positive
NDM-1, loss or decreased OMPs, efflux pump	19	16–256	4–64	4–128
NDM-1+IMP-8, loss or decreased OMPs, efflux pump	1	128	128	32
IMP-8, loss or decreased OMPs, efflux pump	4	8–64	0.25–8	2–8
IMP-4, no loss or decreased OMPs, efflux pump	2	16	0.5–2	0.5–1
KPC-2, loss or decreased OMPs	1	64	8	16
Carbapenemase negative
AmpC, ESBLs, loss or decreased OMPs, efflux pump	42	2–64	0.5–32	0.5–32
AmpC, ESBLs, loss or decreased OMPs	29	2–64	0.25–16	0.25–32
AmpC, loss or decreased OMPs, efflux pump	22	2–64	0.25–16	0.25–8
ESBLs, loss or decreased OMPs, efflux pump	11	2–32	0.25–2	0.25–8
ESBLs, loss or decreased OMPs	2	8	0.25–2	0.25–4
Loss or decreased OMPs, efflux pump	5	2–8	0.25–2	0.25–2

ETP, ertapenem; IPM, imipenem; MEM, meropenem.