Application of quantitative second-line drug susceptibility testing at a multidrug-resistant tuberculosis hospital in Tanzania

Table 1 Minimum inhibitory concentration (MIC) for first-line drugs compared to Bactec MGIT results (N = 22 isolates)

Drug and MIC result	MGIT susceptible	MGIT resistant	Accuracy
Isoniazid			95.5%
MIC Susceptible	4	0
MIC Resistant	1	17^a
Rifampin			90.9%
MIC Susceptible	8	1^b
MIC Resistant	1	12^c
Streptomycin			90.9%
MIC Susceptible	13	0
MIC Resistant	2	7
Ethambutol			59.1%
MIC Susceptible	11	1^e
MIC Resistant	7^f	2

^aAll with isoniazid MIC ≥ 4 μg/ml. ^bRifampin MIC of 1 μg/ml. ^cAll with rifampin MIC >16 μg/ml. ^eEthambutol MIC of 4 μg/ml. ^fFive (71%) with ethambutol MIC of 8 μg/ml.