Figure 4.

Antimycobacterial activity of PZA in cellular and necrotic lesions. (A) Effect of PZA on the bacterial burden of individual lesions in rabbits with active TB, after 5 and 10 wk of daily treatment. C, untreated controls. Median and 95% CI are shown (both median and 95% CI are at 10° for the PZA control groups in the cellular lesion category). Asterisks indicate statistical significance BY using the two-tailed Mann-Whitney U test. (B) Bacterial burden normalized to tissue weight in uninvolved lung tissue (“normal”) and in cellular and necrotic lesions. Because all CFU data are plotted on a log scale, all CFU values are converted to CFU + 1 order to include “zero CFU” data points. This method is not appropriate when normalizing to tissue weight because a difference of 1 would substantially skew the CFU-per-milligram dataset for the zero CFU subset. To visualize zero CFU data points, these were assigned an arbitrary low value of 10⁻⁴, then normalized to tissue weight. The median and 95% CI were calculated by using actual zero values. Medians that do not appear on the graph have a value of zero. (C) Effect of PZA treatment on lesion weight. Asterisks indicate statistical significance by using the Mann-Whitney U test. (D) Effect of PZA on the proportion of sterile lesions after 5 and 10 wk of treatment (actual numbers of sterile versus total lesions are indicated on top of each bar). Data from two independent experiments were combined to generate the plots. Statistically significant differences between two proportions were detected by using Fisher’s exact test. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (43 < n < 98 per treatment group).