Table 2 Classification of isolates of Tuberculosis Regional Reference Laboratory in Mashhad (n = 123) based on antibiotic susceptibility testing and distribution of gyrA and gyrB genes mutation patterns
| Gene | Nucleotide change | Amino acid change | Clinical isolates (n = 111) |
MDR-TB (n = 12) |
Polydrug resistant (n = 0) | |
|---|---|---|---|---|---|---|
|
Pansusceptible (n = 108) |
FQ mono-resistant (n = 3)a | |||||
| gyrA | C(269) → T | Ala(90) → Val | – | – | – | – |
| T(271) → C | Ser (91) → Pro | – | – | – | – | |
| A(281) → G | Asp(94) → Gly | – | 1 (new case) | 2 (XDR)b | – | |
| gyrB | – | – | – | – | – | – |
| Phenotypically FQ resistant, without any gyrase mutations | – | 2 (1 new, 1 relapse) | 1 | – | ||
| All phenotypically FQ resistant | – | 3 | 3c | – | ||
