TABLE 4.
Substitutions in GyrA found in fluoroquinolone-resistant and -susceptible clinical M. tuberculosis isolatesa
| Substitution in GyrA | No. of isolates by resistance type |
% of total substitutions in GyrA | Implication in FQ resistance in M. tuberculosis demonstrated in the literature (reference[s]) | |||
|---|---|---|---|---|---|---|
| FQ-R |
FQ-S |
|||||
| MDR | Non-MDR | MDR | Non-MDR | |||
| T80A | 1b | 7 + 1b | 6 + 1b | 19.9 | No (32, 33) | |
| G88C | 1 | 1.2 | Yes (34) | |||
| A90Ed | 1 | 1.2 | NDc | |||
| A90Gd | 1 | 1 | 2.4 | No (32, 33) | ||
| A90V | 14 + 4b | 22.2 | Yes (33) | |||
| S91P | 5 | 6.2 | Yese | |||
| D94A | 13 | 16.1 | Yese | |||
| D94G | 10 + 1b | 2 | 16.1 | Yes (33) | ||
| D94H | 3 + 1b | 4.9 | Yes (33) | |||
| D94N | 2 + 1b | 1 | 4.9 | Yese | ||
| D94Y | 2 + 1b | 3.7 | Yese | |||
| Q101E | 1 | 1.2 | ND | |||
| Total | 60 | 3 | 9 | 9 | 100 | |
a
Seven isolates harbored 2 substitutions.
b
Isolate harboring two substitutions.
c
ND, not demonstrated.
d
Substitution systematically associated with other GyrA substitutions (see Table 1 for details).
e
Considered to be implicated in FQ resistance despite the absence of unequivocal demonstration, since it is frequently observed in FQ-R strains (11) and is included in the MTBDRsl line probe assay.