Table 4. Average quantification of the relative expression level,by RT-qPCR,of the genes that code for efflux pumps in M. tuberculosisexposed to rifampicin.

	Relative expression level ± SD
Gene	82/09—MDR	149/09—XDR	286/09—XDR	69/11—MDR	29/12—XDR
mmr	1.31 ± 0.62	0.73 ±0.49	2.49 ± 0.49	1.00 ± 0.33	0.71 ± 0.00
mmpL7	1.85 ± 0.87	0.46 ±0.23	3.23 ± 1.09	0.39 ± 0.08	1.02 ± 0.30
Rv1258c	1.40 ± 0.66	1.31 ± 0.44	0.94 ± 0.18	0.20 ± 0.03	0.93 ± 0.31
p55	4.27 ± 1.44	2.30 ± 0.23	9.88 ± 0.97	1.54 ± 0.66	2.59 ± 0.63
whiB7	0.87 ± 0.29	1.61 ± 0.76	1.04 ± 0.16	2.47 ± 0.24	1.83 ± 0.44
Rv1217c	0.71 ± 0.07	0.52 ± 0.07	0.98 ± 0.76	0.14 ± 0.08	1.12 ± 0.57
Rv1218c	0.72 ± 0.40	0.36 ± 0.12	0.69 ± 0.10	0.51 ± 0.05	1.44 ± 0.62
efpA	1.94 ± 0.09	1.83 ± 0.44	1.41 ± 0.47	1.81 ± 0.27	3.47 ± 1.17
Rv2459	0.69 ± 0.35	0.41 ± 0.04	0.74 ± 0.04	0.28 ± 0.08	1.08 ± 0.21
pstB	0.41 ± 0.30	0.46 ± 0.11	0.47 ± 0.04	0.22 ± 0.01	1.41 ± 0.47
iniA	1.94 ± 0.28	0.89 ± 0.25	54.50 ± 21.35	1.47 ± 0.21	3.11 ± 1.20

The relative expression of the 11 genes was determined by comparison of the relative quantity of the respective mRNA in the presence of rifampicin at the MIC to the non-exposed condition. Each strain was assayed in triplicate using total RNA obtained from three independent cultures. Data was normalized to the M. tuberculosis 16S rDNA reference gene and presented as the mean fold change (±SD) compared with the control. Results in bold type were considered to be overexpressed. Relative expression levels above two were considered significantly overexpressed.