TABLE 1.
Distribution and prevalence of fluoroquinolone-resistant strains in China
| FQ | No. of strains with indicated MIC (mg/liter) |
Breakpoint MIC for resistance (mg/liter) | No. (%) of resistant strains | Prevalence of resistant strains (%)a | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | ||||
| OFX | 0 | 0 | 0 | 8 | 48 | 36 | 36 | 8 | 2 | 2.0 | 130 (94.2) | 3.76 |
| LVX | 0 | 3 | 4 | 21 | 73 | 30 | 6 | 0 | 1 | 2.0 | 110 (79.7) | 3.18 |
| MOX | 10 | 20 | 21 | 31 | 29 | 15 | 11 | 1 | 0 | 0.5 | 108 (78.3) | 3.12 |
| GAT | 29 | 63 | 29 | 13 | 2 | 1 | 0 | 1 | 0 | 0.5 | 46 (33.3) | 1.33 |
| SPX | 21 | 51 | 25 | 26 | 13 | 1 | 0 | 0 | 1 | 0.5 | 66 (47.8) | 1.91 |
a
Considering the loss of failure of subculture for 9 strains, the mean prevalence of FQ resistance was estimated according to the formula n = (N × 145)/(138 × 3,634), where n is the prevalence of FQ resistance, N is the total number of FQ-resistant strains, and 145 is the total number of OFX-resistant strains among the 3,634 strains isolated from the national survey of drug-resistant tuberculosis in China.