[Comparative evaluation of the effectiveness of fluoroquinolones in experimental anthrax infection]

Comparative antibacterial activity and protective efficacy of ciprofloxacin, pefloxacin and lomefloxacin were estimated in a model of anthrax. The MICs of the three drugs determined by the method of serial dilutions for three vaccinal strains of Bacillus anthracis were 0.5 to 1.0 microgram/ml. The protective efficacy of the chemotherapeutics in experimental anthrax induced by the spores of the vaccinal strain 71/12, Tsenkovsky was evaluated in mathematically designed four-factor experiments. It depended on the infective dose and the chemotherapy term and amounted in the protective use of the drugs in the daily doses, equivalent to those for humans, to 80-100-percent protection of the animals infected with 10 LD50 of the biological agent, to 50-80-percent protection with the use of 100 LD50, to 40-70-percent protection with the use of 1000 LD50 and to 50-90-percent protection in the therapeutic use of the fluoroquinolones. This was indicative of the fact that the fluoroquinolones were chemotherapeutically highly active in the treatment of experimental anthrax. The marked therapeutic efficacy of the fluoroquinolones and the high percentage of the animal protection after their urgent prophylactic use in a single dose are their obvious merits. The total values of the protective efficacy of the three fluoroquinolones with respect to anthrax were practically the same.