TABLE 2.

Cumulative MIC results for NDM, IMP, and KPC gene-positive isolates for all antimicrobial agents tested^a

Type of isolate and drug	No. of isolates (cumulative %) inhibited at specified concn (μg/ml)																		MIC50 (μg/ml)	MIC90 (μg/ml)	% S	% I	% R
	0.0018	0.0037	0.008	0.015	0.03	0.06	0.125	0.25	0.5	1	2	4	8	16	32	64	128	>128
NDM gene-positive isolates (n = 31)
Imipenem (4 μg/ml relebactam)						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (3.2)	4 (16.1)	10 (48.4)	9 (77.4)	6 (96.7)	1 (100.0)	32		0b	0b	100b
Imipenem						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (3.2)	4 (16.1)	12 (54.8)	7 (77.4)	5 (93.5)	2 (100.0)	32	128	0	0	100
Ertapenem						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (3.2)	3 (12.9)	9 (41.9)	10 (74.2)	8 (100.0)	128	>128	0	0	100
Meropenem						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	4 (12.9)	4 (25.8)	9 (54.8)	10 (87.1)	4 (100.0)	64	>128	0	0	100
Ceftolozane (4 μg/ml tazobactam)						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	31 (100.0)	>128	>128	0	0	100
Cefepime						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	2 (6.4)	2 (12.9)	27 (100.0)	>128	>128	0	NA	100
Ceftriaxone						0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	31 (100.0)	>128	>128	0	0	100
IMP gene-positive isolates (n = 11)
Imipenem (4 μg/ml relebactam)					0 (0.0)	1 (9.1)	0 (9.1)	0 (9.1)	0 (9.1)	1 (18.2)	1 (27.3)	3 (54.5)	1 (63.6)	1 (72.7)	0 (72.7)	0 (72.7)	2 (90.9)	1 (100.0)	4	128	18.2b	9.1b	72.7b
Imipenem					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (9.1)	1 (18.2)	1 (27.3)	2 (45.5)	2 (63.6)	1 (72.7)	0 (72.7)	0 (72.7)	2 (90.9)	1 (100.0)	8	128	18.2	9.0	72.8
Ertapenem					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	2 (18.2)	1 (27.3)	0 (27.3)	4 (63.6)	0 (63.6)	1 (72.7)	1 (81.8)	2 (100.0)	16	>128	0	0	100
Meropenem					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (9.1)	2 (27.3)	0 (27.3)	0 (27.3)	3 (54.5)	1 (63.6)	1 (72.7)	1 (81.8)	2 (100.0)	0 (100.0)	8	128	27.3	0	72.7
Ceftolozane (4 μg/ml tazobactam)					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (9.1)	0 (9.1)	0 (9.1)	1 (18.2)	9 (100.0)	>128	>128	0	0	100
Cefepime					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (9.1)	2 (27.3)	1 (36.4)	1 (45.5)	0 (45.5)	6 (100.0)	>128	>128	0	NA	91.9
Ceftriaxone					0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (9.1)	2 (27.3)	8 (100.0)	>128	>128	0	0	100
KPC gene-positive isolates (n = 110)
Imipenem (4 μg/ml relebactam)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	5 (5.4)	15 (19.0)	23 (40.0)	20 (58.2)	21 (77.3)	15 (90.9)	4 (94.5)	1 (95.4)	1 (96.4)	2 (98.2)	1 (99.1)	0 (99.1)	0 (99.1)	1 (100.0)	0.25	1	90.9b	3.6b	5.4b
Imipenem	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	1 (1.8)	1 (2.7)	3 (5.4)	16 (20.0)	15 (33.6)	20 (51.8)	21 (70.9)	11 (80.9)	7 (87.3)	14 (100.0)	16	>128	2.7	2.7	94.5
Ertapenem	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	0 (1.0)	0 (1.0)	0 (1.0)	2 (1.8)	1 (3.6)	4 (7.3)	9 (15.4)	12 (26.4)	16 (40.9)	20 (59.1)	22 (79.1)	23 (100.0)	64	>128	1.0	1.8	97.2
Meropenem	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	0 (1.0)	0 (1.0)	0 (1.0)	3 (3.6)	3 (6.4)	11 (16.4)	13 (28.2)	13 (40.0)	24 (61.8)	9 (70.0)	3 (72.7)	30 (100.0)	32	>128	3.6	2.7	93.6
Ceftolozane (4 μg/ml tazobactam)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	1 (1.8)	1 (2.7)	1 (3.6)	1 (4.5)	5 (9.0)	13 (20.9)	21 (40.0)	37 (73.6)	29 (100.0)	128	>128	2.7	1.0	96.3
Cefepime	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	0 (1.0)	0 (1.0)	1 (1.8)	4 (5.4)	7 (11.8)	9 (20.0)	6 (25.4)	9 (33.6)	10 (42.7)	63 (100.0)	>128	>128	1.8	NA	88.2
Ceftriaxone	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	0 (0.0)	1 (1.0)	1 (1.8)	0 (1.8)	1 (2.7)	1 (3.6)	0 (3.6)	5 (8.2)	8 (15.4)	93 (100.0)	>128	>128	1.0	1.0	98.2

^aS, susceptible; I, intermediate; R, resistant; NA, not applicable.

^bUsing imipenem breakpoints.