TABLE 3.
Characteristics of spontaneous RFB-resistant mutants of M. abscessusa
| MIC (μg/ml) | Mutation in rpoB |
||
|---|---|---|---|
| Strain | SNP | AA change | |
| CIP104536T (R) | 12.5 | ||
| 25.1 | 50 | C1339T | H447Y |
| 25.2 | 100 | C1339G | H447D |
| 50.1 | 50 | C1339T | H447Y |
| 50.2 | 50 | C1355T | S452L |
a
MICs (μg/ml) were determined in cation-adjusted Mueller-Hinton broth. Resistant strains were derived from the rough M. abscessus CIP104536T parental strain on Middlbrook 7H10 supplemented with either 25 or 50 μg/ml RFB. Single-nucleotide polymorphism identification in rpoB (MAB_3869c) and corresponding amino acid changes are also indicated. RFB, rifabutin; AA, amino acid.