TABLE 3

Proportions of nude mice with selective amplification of resistance and emergence of resistance between month 2 and month 6

Treatment groupDrug regimenNo. of mice with indicated result/total no. of mice
Selective amplification onlyaResistanceb
0–2 mos2–6 mosHRH or RHRH or R
2P 5/7P 5/70/91/101/100/99/109/10
3RHZE 5/7RH 5/70/100/100/100/100/100/10
4P 1/70/100/100/100/101/101/10
5PH50 1/70/100/100/100/100/100/10
62wRHZE 5/7 + 6wRH25Z300E200 2/7RH25 2/70/100/100/100/100/100/10
7P 1/70/101/101/101/106/106/10c
8PH50 1/70/100/100/103/101/104/10
9P15H50 1/70/100/100/102/100/102/10
10P20H50 1/70/100/100/100/101/101/10
112wRH5ZE 5/7 + 6wRH12.5Z300E200 2/7RH12.5 2/70/101/10d1/104/10d0/104/10
12P 1/70/101/101/102/10d5/105/10d
13PH25 1/70/100/100/101/101/102/10
14P15H25 1/70/100/100/101/100/101/10
15P20H25 1/70/100/100/101/101/102/10
  • Drug doses (in mg/kg) if not otherwise specified: rifampin (R,10); rifapentine (P, 10); isoniazid (H, 10); pyrazinamide (Z, 150); ethambutol (E, 100).

  • a Selective amplification defined by 0.01 < H < 1% or 0.001 < R < 1% of resistance on H (0.2 μg/ml) or R (1.0 μg/ml).

  • b Resistance defined by resistant CFU comprising ≥1% of total CFU.

  • c One isolate was multidrug resistant (MDR) which was resistant to both H (0.2 μg/ml) and R (1.0 μg/ml).

  • d One isolate had heterogenous strains which were resistant to either H (0.2 μg/ml) or R (1.0 μg/ml) but not both.