Prevalence and Molecular Characterization of Second-Line Drugs Resistance among Multidrug-Resistant Mycobacterium tuberculosis Isolates in Southwest of China

Table 5

The characteristics of gyrA and gyrB gene mutations in 156 MDR isolates.

(Number of isolates)	Locus	Codon/nucleotide change(s)	Amino /nucleotide change(s)	Number of strains	Number (%)
OFX-resistant (66)	gyrA	NM	NM	13	19.7
		GGC→TGC	Gly88Cys	1	1.5
		GAC→AAC	Asp89Asn	1	1.5
		GCG→GTG	Ala90Val	13	19.7
		TCG→CCG	Ser91Pro	3	4.5
		GAC→AAC	Asp94Asn	6	9.1
		GAC→GCC	Asp94Ala	10	15.2
		GAC→GGC	Asp94Gly	13	19.7
		GAC→TAC	Asp94Tyr	1	1.5
		GCC→TCC/GAC→GGC	Ala74Ser/Asp94Gly	1	1.5
		GCG→GTG/GAC→GCC	Ala90Val/Asp94Ala	2	3.0
		GCG→GTG/GAC→GGC	Ala90Val/Asp94Gly	1	1.5
		GGC→GCC/GCG→GTG	Gly88Ala/Ala90Val	1	1.5
	gyrB	NM	NM	62	93.9
		GAC→AAC	Asp461Asn	1	1.5
		GGG→AGG	Gly512Arg	3	4.5
OFX-susceptible (90)	gyrA	NM	NM	85	94.4
		GGC→GCC	Gly88Ala	1	1.1
		GCG→GTG	Ala90Val	2	2.2
		GAC→GCC	Asp94Ala	2	2.2
	gyrB	NM	NM	86	95.6
		GAC→AAC	Asp461Asn	3	3.3
		GGG→AGG	Gly512Arg	1	1.1
KAN-resistant (26)	rrs	NM	NM	7	26.9
		G→A	G1339A	1	3.8
		A→G	A1401G	18	69.2
	eis	NM	NM	22	84.6
		G→A	G(−10)A	3	11.5
		C→T	C(−14)T	1	3.8
KAN-susceptible (130)	rrs	NM	NM	129	99.2
		A→G	A(1449)G	1	0.8
	eis	NM	NM	129	99.2
		G→A	G(−10)A	1	0.8

NM, no mutation; acid numbers are based on homologous mutations in Escherichia coli.