Prevalence of extensively drug-resistant tuberculosis in a Chinese multidrug-resistant TB cohort after redefinition

Table 2 Mutations in the quinolone resistance-determining region (QRDR) of gyrA and gyrB and fluoroquinolone MICs

Mutations in QRDR	N (%)	FQ	No. of isolates with corresponding MIC (mg/L)
Mutations in QRDR	N (%)	FQ	0.12	0.25	0.5	1	2	4	8
GyrA Asp89Asn	2 (0.6)	MFX	0	1	1	0	0	0	0
		OFX	0	0	0	0	0	2	0
		LFX	0	0	0	0	1	1	0
GyrA Ala90Val	76 (24.4)	MFX	18	3	16	23	8	8	0
		OFX	0	0	0	0	17	38	21
		LFX	0	0	0	0	56	20	0
GyrA Ser91Pro	33 (10.6)	MFX	3	9	10	4	7	0	0
		OFX	0	0	0	3	7	19	4
		LFX	0	0	0	4	25	4	0
GyrA Asp94Ala	17 (5.5)	MFX	0	0	10	4	3	0	0
		OFX	0	0	0	0	2	12	3
		LFX	0	0	0	0	15	2	0
GyrA Asp94Asn	19 (6.1)	MFX	0	0	4	4	7	4	0
		OFX	0	0	0	0	3	4	12
		LFX	0	0	0	0	4	15	0
GyrA Asp94Gly	96 (30.9)	MFX	0	0	10	14	44	28	0
		OFX	0	0	0	0	3	9	84
		LFX	0	0	0	0	11	85	0
GyrA Asp94His	4 (1.3)	MFX	0	0	0	0	0	4	0
		OFX	0	0	0	0	0	0	4
		LFX	0	0	0	0	0	4	0
GyrA Asp94Tyr	3 (1.0)	MFX	0	0	0	0	3	0	0
		OFX	0	0	0	0	0	0	3
		LFX	0	0	0	0	0	3	0
GyrA Asp94Val	8 (2.6)	MFX	0	0	0	2	4	2	0
		OFX	0	0	0	0	2	4	2
		LFX	0	0	0	0	4	4	0
GyrB Ser447Phe	2 (0.6)	MFX	2	0	0	0	0	0	0
		OFX	0	0	0	0	0	2	0
		LFX	0	0	0	0	2	0	0
GyrB Asp461Asn	1 (0.3)	MFX	0	0	0	0	1	0	0
		OFX	0	0	0	0	0	0	1
		LFX	0	0	0	0	0	1	0
GyrB Asp500Asn	1 (0.3)	MFX	0	0	1	0	0	0	0
		OFX	0	0	0	0	0	1	0
		LFX	0	0	0	0	1	0	0
GyrB Ala504Thr	3 (1.0)	MFX	0	0	0	0	0	3	0
		OFX	0	0	0	0	0	0	3
		LFX	0	0	0	0	0	3	0
WT	46 (14.7)	MFX	0	7	15	12	8	4	0
		OFX	0	0	0	1	15	21	9
		LFX	0	0	1	3	24	16	2
Total	311 (100.0)	MFX	23	20	67	63	85	53	0
		OFX	0	0	0	4	49	112	146
		LFX	0	0	1	7	143	158	2

MIC, minimum inhibitory concentration; WT, wild-type; FQ, fluoroquinolone; MFX, moxifloxacin; OFX, ofloxacin; LFX, levofloxacin

ISSN: 2047-2994