Figure 1. Lung CFU and relative lung weights of mice.

A: Relative lung weights were calculated as a percentage of total body mass (mean +− SE). Black squares: uninfected placebo, open squares: uninfected RIF+INH treated, black circles: infected placebo, open circles: infected RIF+INH treated mice. At start of treatment, relative lung weights were increased in infected mice compared to uninfected mice (p<0.001). After an initial increase within 3 days, relative lung weight started to decrease within 3–7 days after start of treatment with RIF+INH in the infected mice although remaining higher than in the uninfected mice until the end of the experiment (p<0.01). Treatment had no effect on lung weight in uninfected mice. B: CFU counts of lung homogenates of sacrificed mice. Median baseline level in infected mice prior to treatment was 1.3×10⁶CFU per lung (black squares) and similar levels were found after 7 and 21 days of placebo treatment (black circles, 3 days not available due to contamination of culture plates). Treatment with RIF+INH strongly reduced CFU counts within 7 days (open circles; detection limit 2×10³ CFU/lung). Counts from 1 mouse are not available due to contamination. Cultures of undiluted lung homogenates from uninfected mice yielded no TB colonies (not shown). ** p<0.01