Table 8.

MGIT-DST of PZA ^R-Mtb with DFO-B alone and in combination with PZA

Mtb Isolate	DFO-B (mg/mL)			DFO-B (mg/mL) + PZA 100 μg/mL			Ferric citrate + DFO-B (mg/mL)
	0.25	0.5	1.0	0.25	0.5	1.0	1
PZA R isolate 1	209	41	0	0	0	0	400
PZA R isolate 2	129	0	0	0	0	0	400
MDR + PZA R isolate 3	400	400	0	7	0	0	400
MDR + PZA R isolate 4	400	400	179	400	400	400	400
MDR + PZA R isolate 5	400	400	0	0	0	0	400
MDR + PZA R isolate 6	400	400	400	400	400	400	400
MDR + PZA R isolate 7	400	400	0	400	400	0	400
INFERENCE	R	S n = 2	S n = 5	S n = 4	S n = 4	S n = 5	R

GU value of GC for all seven isolates was 400. GU value in PZA-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 and DFO-B + PZA on seven PZA ^R isolates: The medium used was Middlebrook 7H9 broth, pH = 5.9 incubated at 37 °C for 14 days in the MGIT instrument