TABLE 3.

Rifampin resistance mutations and fitness of various bacterial species assayed in competition experiments in culturesa

Bacterial speciesrpoB mutationRelative fitnessReference
E. coliHis526→Tyr0.9119
His526→Leu0.94
S. aureusHis481→Tyr (corresponds to E. coli codon 526)0.9329
His481→Asn (corresponds to E. coli codon 526)1.00
Ser486→Leu (corresponds to E. coli codon 531)0.86
M. tuberculosisHis526→Tyr0.792
Ser531→Leu0.84*
M. tuberculosisHis526→Tyr0.89This work
Ser531→Trp0.67
  • a Only the subset of mutations that have been identified in all three species are shown. *, calculated as the average of four independent mutants (2).