TABLE 1.

Categorization of CECR-KP isolates according to the results of phenotypic detection methods for AmpC, ESBLs, and MBLs

Isolate group	No. of isolates	Three-dimensional test result for AmpC detectiona	Double-disk test result for ESBL detection	Double-disk test result for MBL detection	NCCLS confirmatory test result for ESBLs
					Zone diameter change on CAZ (mm)b	Zone diameter change on CTX (mm)b	No. (%) of test-positive isolates
1a	30	Positive	Negative	Negative	+1 to +4	0 to +1	0 (0)
1b	12	Positive	Negative	Negative	−4 to −8	0 to −5	0 (0)
2a	10	Positive	Positive	Negative	−2 to −4	+8 to +14	9 (100)
2b	6	Positive	Positive	Negative	+1 to +3	+12 to +14	5 (100)
2c	19	Positive	Positive	Negative	+1 to +5	+2 to +6	9 (47.4)
3	2	Positive	Negative	Positive	+4, +6	+2, +4	1 (50.0)
4	9	Negative or indeterminate	Positive	Negative	+6 to +17	+7 to +14	9 (100)
5	11	Negative or indeterminate	Negative	Negative	+1 to +3	+1 to +3	11 (0)

^aThe results were interpreted and grouped as described by Manchanda and Singh (7).

^bChanges in zone diameters of disks of ceftazidime (CAZ) and cefotaxime (CTX) plus clavulanic acid in comparison with those of drug disks-without clavulanic acid.