Chemotherapy of mice experimentally infected with Shigella flexneri.

A chronic infection with Shigella flexneri 2a has been established in mice for the evaluation of compounds for therapeutic potential. Evidence of infection is indicated by prolonged symptomless excretion in the feces and by positive isolation of organisms from different segments of the intestinal tract and from mesenteric lymph nodes. Serum antibody titer reaches a maximum after 9 days of infection and remains at a low level until 32 days postinfection. In this model, five drugs used in human shigellosis were evaluated for efficacy. Ampicillin was found to be the most active followed by oxytetracycline and kanamycin. Neomycin and colistin were the least active in this system.