Table 6.

MGIT-DST of MDR-Mtb with DFO-B alone and in combination with INH and RIF

MDR- Mtb (INH R + RIF R) Isolate	DFO-B (mg/mL)			DFO-B (mg/mL) + INH 0.1 μg/mL			DFO-B (mg/mL) + RIF 1.0 μg/mL			Ferric citrate + DFO-B (mg/mL)
	0.25	0.5	1.0	0.25	0.5	1.0	0.25	0.5	1.0	1.0
1	400	400	0	400	400	0	400	400	0	400
2	400	400	0	400	400	0	400	400	0	400
3	400	0	0	400	0	0	400	0	0	400
4	400	0	0	400	0	0	400	0	0	400
5	400	400	400	400	400	400	400	400	400	400
6	400	400	0	400	0	0	400	0	0	400
7	400	400	0	400	400	0	400	400	0	400
8	400	0	0	400	0	0	400	0	0	400
9	400	0	0	400	0	0	400	0	0	400
10	400	400	0	400	400	0	400	400	0	400
INFERENCE	R	S n = 4	S n = 9	R	S n = 5	S n = 9	R	S n = 5	S n = 9	R

GU value of GC for all ten 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 DFO-B, DFO-B + INH, DFO-B + RIF on ten different clinical isolates of MDR-Mtb (INH-, RIF- and PZA-resistant). The medium used was Middlebrook 7H9 broth, pH = 7 incubated at 37 °C for 14 days in the MGIT instrument