Murine evaluation of drug combinations. (a) Treatment induced bacterial reduction compared to the untreated control (isoniazid p = 0.0159, ethambutol p = 0.0159, NZX p = 0.0159). Combination treatment with ethambutol/NZX reduced bacterial load significantly more than ethambutol treatment alone (p = 0.0317), but not from NZX treatment alone (p = 0.4206). We found no significant difference between the other groups. Results presented as mean ± sd. All p values were calculated by unpaired Student’s t-test, Mann–Whitney or ANOVA (*p < 0.05). (b) Representative eosin (H&E) staining showing lung sections from M. tuberculosis H37Rv infected mice and uninfected control mice. H&E staining of untreated lungs showed tissue destruction and granuloma formation. Mice treated for four weeks with INH, NZX or NZX/EMB showed decreased tissue destruction. Scale bar 200 μm. (c) Results of the blinded lung inflammatory score. Data are presented as the mean ± SEM (n = 4–5). p values were determined using a one-way ANOVA with Tukey’s post hoc test. *p ≤ 0.05; **p ≤ 0.01.