TABLE 1.
Mutations at codon 315 of katG and in the mabA-inhA regulon detected by DNA sequencing in INH-resistant M. tuberculosis clinical isolates
| DNA target | No. of isolates tested | Nucleotide substitution | Amino acid change | No. (%) of isolates with mutations |
|---|---|---|---|---|
| katG gene fragment | 223 | AGC→ACC | Ser→Thr | 187 (83.9) |
| AGC→ACA | Ser→Thr | 1 (0.4) | ||
| AGC→CGC | Ser→Arg | 1 (0.4) | ||
| AGC→AAC | Ser→Asn | 2 (0.9) | ||
| AGC→ATC | Ser→Ile | 1 (0.4) | ||
| None | None (wild type) | 31 (13.9) | ||
| mabA-inhA regulon | 52a | −15C→Tc | 7 (13.5) | |
| 52b | −15C→Tc | 10 (19.2) |
a
Isolates carrying wild-type codon 315 of the katG gene.
b
Isolates carrying mutations at codon 315 of the katG gene.
c
The mutation designation is given as the nucleotide base pair relative to the initiation codon (+1) of the mabA gene according to the study of Ramaswamy and Musser (11).