Table 3.

Detailed results of the three combined-disk tests employing imipenem with 300 μg APBA, 600 μg APBA, or 400 μg PBA against the 112 KPC-positive and 127 non-KPC-producing isolates

β-Lactamase	Imipenem + 300 μg APBA (≥5 mm)				Imipenem + 600 μg APBA (≥5 mm)				Imipenem + 400 μg PBA (≥5 mm)
	Increase in inhibition zone diam (mm)a		No. of isolates		Increase in inhibition zone diam (mm)		No. of isolates		Increase in inhibition zone diam (mm)		No. of isolates
	Range	Mean increase	Positive	Negative	Range	Mean increase	Positive	Negative	Range	Mean increase	Positive	Negative
KPC (n = 112)	2 to 8	5	72	40	3 to 9	6	92	20	5 to 12	9	112	0
VIM (n = 58)	0 to 2	0	0	58	0 to 3	0	0	58	0 to 3	1	0	58
AmpC (n = 47)	−2 to 5	1	3	44	−2 to 6	0	3	44	0 to 7	2	3	44
ESBL (n = 22)	−3 to 1	−1	0	22	−2 to 1	−1	0	22	0 to 3	2	0	22
Total non-KPC (n = 127)	−3 to 5	0	3	124	−2 to 6	0	3	124	0 to 7	2	3	124

^aIncrease in inhibition zone diameter around imipenem disks containing β-lactamase inhibitors.