TABLE 1.

Test results for clinical strains of M. tuberculosis (n = 200) for susceptibility to SIRE and PZA

Antibiotic (concn [μg/ml])	MGIT 960 resulta	RRM resulta		Overall agreement (%)	Sensitivityb (%)	Specificityc (%)	PPVd (%)	NPVe (%)
		S	R
STR (1.0)	S	37	6	97	96	100	100	86
R	157
STR (4.0)	S	82	16	92	86	100	100	84
R	102
INH (0.1)	S	30	3f	99	98	100	100	91
R	167
INH (0.4)	S	31	3f	99	98	100	100	91
R	166
RIF (1.0)	S	68		100	100	100	100	100
R	132
EMB (5.0)	S	103	71	65	27	100	100	59
R	26
EMB (7.5)	S	156	33	84	25	100	100	83
R	11
PZA (100)g	S	158	8	92	77	98	90	95
	R	3	26

^aS, susceptible; R, resistant. Values are numbers of isolates.

^bThe sensitivity, i.e., the ability of MGIT 960 to detect true resistance compared with the RRM results.

^cThe specificity, i.e., the ability of MGIT 960 to detect true susceptibility compared with the RRM results.

^dPPV, positive predictive value.

^eNPV, negative predictive value.

^fMixed cultures (consisting of resistant and susceptible subpopulations).

^gFive M. tuberculosis isolates did not grow in one of the systems used.