TABLE 2.
MICs (agar dilution) of rifampin and rifabutin for H. pylori with wild-type rpoB sequence (DR62a and 2802A) and for H. pylori harboring a novel mutation, V149F (DR62n and 2802A-R)a
| Strain | Codon no. (V149/V176) and amino acid | MIC (μg/ml)
|
|
|---|---|---|---|
| Rifampin | Rifabutin | ||
| H. pylori | |||
| DR62a | 0.25 | 0.002 | |
| DR62n | V149F | 16 | 8 |
| 2802A | 0.25 | 0.008 | |
| 2802A-R | V149F | 16 | 16 |
| M. tuberculosisb | |||
| 69 | 1 | 0.03 | |
| 71 | 2 | 0.5 | |
| 72 | 4 | 1 | |
| 75 | V176F | 8 | 1 |
| 83 | V176F | 32 | 2 |
| 84 | V176F | 32 | 2 |
a
The equivalent mutation (V176F) was seen for three of six M. tuberculosis samples with the rifampin resistance phenotype but the wild-type cluster region.
b
M. tuberculosis strain designations are from the work of Yang et al. (17). The data for M. tuberculosis come from 6 samples out of 100 of a collection of M. tuberculosis isolates for which MICs of rifamycin are elevated.