TABLE 3.

Mtz sensitivity analysis of Mtz-sensitive H. pylori strains with inactivated fdxB, frxA, and rdxA genes

H. pylori strain	MIC (μg/ml) for the clinical isolate or mutant straina:
	Clinical isolates	fdxB::catb	frxA::cat	rdxA::cat	ureBc::cat	fdxB::cat rdxA::kmd	frxA::cat rdxA::km	ureB::cat rdxA::km
2714	1	1	32	32	1	64	128	32
2393	1	4	32	32	1	64	128	32
2667	1	2	32	32	1	64	128	32
2600	2	2	128	128	2	128	>256	128
2201	2	2	32	32	2	64	128	32
2399	4	2	32	32	2	64	128	32
2418	4	2	32	32	2	64	128	32

^aMICs were determined by growth on 7% horse blood–BHI agar plates supplemented with 0.5, 1, 2, 4, 8, 16, 32, 64, 128, or 256 μg of Mtz per ml and incubation for 4 days. The results were confirmed twice by measuring all MICs at the same time. 

^bcat, chloramphenicol resistance gene. 

^cureB::cat was used as a negative control. 

^dkm, kanamycin resistant gene.