Table 5.

MGIT-DST of MDR-Mtb with Exo-MS alone and in combination with INH and RIF

MDR- Mtb (INH R + RIF R) Isolate	Exo-MS (mg/mL)			Exo-MS (mg/mL) + INH 0.1 μg/mL			Exo-MS (mg/mL) + RIF 1.0 μg/mL			Ferric citrate + Exo-MS (mg/mL)
	0.125	0.25	0.5	0.125	0.25	0.5	0.125	0.25	0.5	0.5
1	400	400	400	400	400	400	400	400	400	400
2	400	400	0	400	400	0	400	400	0	400
3	400	400	0	400	400	0	400	400	12	400
4	400	400	400	400	400	400	400	400	400	400
5	400	400	253	400	400	105	400	400	131	400
INFERENCE	R	R	S n = 2	R	R	S n = 2	R	R	S n = 2	R

GU value of GC for all five isolates was 400. GU value in INH- and RIF-containing medium for all isolates was also 400. R resistant, S Susceptible. If the GU value of the drug-containing tube is ≥100, the interpretation is Resistant by the MGIT instrument. If the GU value of the drug tube is <100, the interpretation is Susceptible (n = no. of isolates susceptible)

Inhibitory effect of Exo-MS, Exo-MS + INH, Exo-MS + RIF on five clinical isolates of MDR-Mtb (INH-, RIF- and PZA-resistant). The medium used was Middlebrook 7H9 broth, pH = 7 incubated at 37 °C for14 days in the MGIT instrument