Table 1.

Mutant rpoB alleles in 177 rifampin-resistant clinical isolates of M. tuberculosis

Isolate pheno- typeAmino acid(s) affectedaAmino acid change(s)No. of isolates (frequency [%])Origin of isolate(s) (no.)
Resistantb509, 526Ser→Thr, His→Asp1 (0.6)Canada (1)
511Leu→Pro1 (0.6)U.S.c(1)
513Gln→Leu1 (0.6)U.S. (1)
513Gln→Pro2 (1.1)Philippines (1), U.S. (1)
514Phe insertion1 (0.6)U.S. (1)
516Asp→Val13 (7.4)U.S. (9), Switzerland (1), Peru (1), Yemen (2)
516Asp→Gly1 (0.6)U.S. (1)
517Gln deletion1 (0.6)U.S. (1)
518Asn deletion2 (1.1)U.S. (2)
519Asn→Lys1 (0.6)U.S. (1)
521Leu→Met1 (0.6)U.S. (1)
522Ser→Leu2 (1.1)U.S. (1), Japan (1)
522, 516Ser→Leu, Asp→Val1 (0.6)Honduras (1)
526His→Pro4 (2.3)Japan (1), Peru (1), U.S. (2)
526His→Leu5 (2.9)Rwanda (1), U.S. (4)
526His→Asp8 (4.6)Switzerland (1), U.S. (7)
526His→Arg9 (5.2)Rwanda (2), Japan (4), U.S. (3)
526His→Tyr35 (20.0)U.S. (30), Yemen (1), Peru (1), Philippines (1), Honduras (2)
527Lys→Gln1 (0.6)U.S. (1)
527, 526Lys→Gln, His→Pro1 (0.6)U.S. (1)
531Ser→Leu74 (42.0)Belgium (1), Japan (5), Rwanda (9), Canada (2), Philippines (3), Vietnam (1), Yemen (4), U.S. (44), Peru (2), Honduras (3)
531Ser→Phe1 (0.6)U.S. (1)
533Leu→Pro3 (1.7)U.S. (2), Philippines (1)
NoneNone8 (4.6)Rwanda (2), Berundi (1), U.S. (5)
SusceptibleNoneNone50U.S. (42), Honduras (8)
  • a Amino acid numbers correspond to theE. coli numbering system for the RNA polymerase β-subunit.

  • b Resistant to rifampin at 2 μg/ml by the BACTEC radiometric method or at 1 μg/ml by the proportion method.

  • c U.S., United States.