Effect of compound 1950 on F. tularensis infection. (A) Survival of mice (n = 10) infected i.n. with 1 × 103 CFU F. tularensis strain SchuS4 (10 × LD50). Treatment with saline (untreated), spectinomycin (50 mg kg−1, BID), or 1950 (50 or 75 mg kg−1, BID) administered s.c. started at 1 h post-infection and continued for 14 days. Mice were monitored for morbidity and mortality for 55 days. # Significantly different from untreated control (P ≤ 0.0001) and spectinomycin control (P ≤ 0.0013). (B) Survival of mice infected i.n. with 900 CFU F. tularensis strain SchuS4 (10 × LD50). Treatment with saline (untreated), spectinomycin (50 mg kg−1, TID), or 1950 (50 mg kg−1, TID) administered s.c. was initiated at 1 h post-infection and continued for 14 days. Mice were monitored for morbidity and mortality for 37 days. # Significantly different from untreated control (P < 0.0001) and the spectinomycin control mice (P = 0.0315).