TABLE 1.

rpoB mutations and MICs of the 189 in vitro-selected RIF-resistant M. tuberculosis mutants

Base pair mutation(s) (no. of strains)	Amino acid mutation(s)	Total no. of strains with mutation(s) (n = 189)	No. of strains
			Beijing (n = 89)		Non-Beijing (n = 100)
			MIC of ≤16	MIC of ≥32	MIC of ≤16	MIC of ≥32
Single nucleotide substitutions (n = 172)
TCG → TTG	Ser531Leu	55		20		35
CAC → TAC	His526Tyr	42		20		22
TCG → TTG	Ser522Leu	25	5	7	5	8
CAC → CGC	His526Arg	26		16		10
TCG → TGG	Ser531Trp	10		4		6
CAC → GAC	His526Asp	6		3		3
CAA → AAA	Gln513Lys	2		1		1
GAC → GTC	Asp516Val	2	1	1
AAC → AAG	Asn519Lys	1			1
CAC → CCC	His526Pro	1		1
CTG → CCG	Leu533Pro	1			1
CGA → CCA	Arg529Pro	1		1
Deletions (n = 14)
ΔGAC	516	2		1		1
ΔAAC	518	2			2
ΔCAG AAC	517-518	1		1
ΔTG G	515-516	1				1
ΔG GA	515-516	1		1
ΔG CTG AGC CA	510-512	1			1
ΔTC ATG G	514-516	1		1
ΔAGC CAA TTC ATG	512-515	1				1
ΔCAA TTC ATG GAC	513-516	2		2
ΔG TTG ACC CA	523-526	1				1
ΔGC CAA TTC ATG GAC CAG A	512-517	1		1
Multiple mutations (n = 2)
CAC → CCC, AAG → CAG	His526Pro, Lys527Gln	1		1
TTG → TGG, ACC → CCC, ΔACA	Leu524Trp, Thr525Pro, 526-527	1		1
None	Wild-type RRDR	1				1
Total		189	6	83	10	90