FIGURE 4.

Comparative assessment of treatment efficacy of the standard and CFZ-containing regimens in a murine model of chronic progressive MAC-PI. (A) Schematic design of the in vivo experiment. BALB/c mice were infected with the M. avium SMC #7 clinical isolate via aerosolization, achieving a mean initial bacterial number of 2 × 10⁵ CFUs in the lungs. Two weeks and 4 weeks of therapy were initiated with the standard and CFZ-containing regimens at 8 weeks post-infection. The daily drug doses were 100 mg/kg for CLR and EMB, 10 mg/kg for RIF and 20 mg/kg for CFZ. The mice were euthanized, and the lungs were homogenized for histopathological examination and bacterial counts at 2 and 4 weeks post-treatment. Plotted infection data and mean CFU counts and bar graphs for the log₁₀ reduction in CFU from treatment initiation in the (B) lungs, (C) spleens and (D) livers were assessed after 2 and 4 weeks of treatment with the two regimens by plating serially diluted tissue lysates onto 7H10-OADC agar plates. The broken vertical line of each plotted data indicates the day of treatment initiation. The statistical significance in (B–D) was calculated by one-way ANOVA followed by Tukey’s multiple comparison test, and the results are represented as the mean value ± S.D. **p < 0.01, ***p < 0.001 and n.s., not significant. MAC-PI, M. avium complex-pulmonary infection; CTL, untreated control; CLR-EMB-RIF, standard regimen; CLR-EMB-CFZ, CFZ-containing regimen.