Detection of second-line drug resistance in Mycobacterium tuberculosis using oligonucleotide microarrays

BMC Infectious Diseases

Table 1 Correlation of the detected mutations in the gyrA and gyrB genes with phenotypic DST

Mutation		No. of isolates	Resistance (mg/L)	MIC Bactec MGIT 960 (mg/L)
gyrA	gyrB	No. of isolates	OFX	LVX	MFX
D94G	wt	1	10	8	2
D94G^a	wt	12	2 to 10	4 to 16	2
D94A^a	wt	6	2	2	0.5 to 2
D94N^a	wt	1	2	8	4
D94H^a	wt	1	10	4	2
D94Y^a	wt	1	2	4	1
A90V^a	wt	9	2 to 10	2 to 8	0.5 to 2
S91P^a	wt	1	2	2	1
G88C	wt	1	10	8	4
A90V + D94G^a	wt	1	10	>32	8
A90V + D94Y^a	wt	1	2	2	1
H70R + G88A^a	wt	2	2	2	1 to 2
H70R + A90V^a	wt	1	2	8	2
S95T	D500H	1	2	4	0.5
S95T	R485H	1	2	1	0.25
S95T	N538D	1	2	2	0.5
S95T	wt	1	2	1	0.125
S95T	wt	17	S	≤0.5	≤0.25
wt	wt	6	S	≤1	≤0.25
wt	wt	(H37Rv)	S	0.5	0.125

^aadditional mutation S95T.
Resistance to OFX was detected by the absolute concentration method. For LVX and MFX, resistance was defined as LVX (>2 mg/L) and MFX (>0.25 mg/L). The MICs considered to reflect resistance are highlighted in bold.

ISSN: 1471-2334