ANALYSIS OF THE THERAPEUTIC EFFICACY OF DIHYDROSTREPTOMYCIN AND TETRACYCLINE AGAINST EXPERIMENTAL TULAREMIC INFECTIONS IN MICE

Abstract

The therapeutic efficacy of antibiotics against the experimental tularemia in mice was studied analytically, and that
1. The infectious features in experimental tularemia employed in the present experiment nearly resembled those in human typhoid diseases.
2. Both dihydrostreptomycin and tetracycline were strikingly effective against tularemia and the treatment with chloramphenicol, kanamycin and erythromycin was progressively less effective.
3. In both cases of dihydrostreptomycin and tetracycline treatments that resulted in survival of 100% of the mice infected with B. tularense, the serum levels attained by the former treatment was approximately 10-times greater than the latter.
4. Dihydrostreptomycin was rapidly bactericidal against B. tularense in vitro at a high concentration, whereas it was bacteriostatic in the blood stream. On the other hand, tetracycline was bacteriostatic chiefly against the organisms both in vitro and in vivo.
5. In the dihydrostreptomycin treatment of tularemia, the pathogenic organisms were eradicated rapidly from the blood stream and spleen, whereas they persisted for a long period of time in the spleen when treated with tetracycline.
6. Dihydrostreptomycin treatment in the early stages of tularemic infection did not suppress the development of immunity.
7. In the course of infection-treatment of the mice infected with virulent B. tularense, immunity (host resistance) developed rapidly from the early stage of the infection.