[An experimental study on pyogenic osteomyelitis with special reference to the analysis of the therapeutic effects of antibiotics in vivo (author's transl)].

Experimental osteomyelitis was produced in mice by the Ueno's method for the purpose of evaluating therapeutic effects of the antibiotics. The results were as follows: 1) Experimental osteomyelitis produced with penicillin-G sensitive bacteria was completely cured by PC-G 1.8 mg per mouse a day, which provided maintenance of the concentration in serum more than 10 times of MIC for over 12 hours. The dosis of 0.18 mg per mouse per day was insufficient to bring a complete healing. 2) Experimental osteomyelitis produced with penicillin-G resistant bacteria did not heal completely, despite the administration of MPI-PC, a synthetic penicillin designed against penicillin resistant staphylococci, in a dosis of 5 mg twice a day, probably by the following reasons. Since MPI-PC is water-soluble, it is difficult to maintain the concentration in serum more than 10 times of MIC for over 1 hour. In other word, the bacteria was exposed to the effective antibiotic concentration for only one hour twice a day. 3) It was experimentally proved that earlier administration of antibiotics following inoculation provided quicker elimination of bacteria. 4) When bactericidal antibiotics were used, administration twice a day in half dosis gave better results compared with the full dosis once a day. 5) This experimental model of osteomyelitis proved quite useful for quantitative analysis of the effects of antibiotics, which would be applicable as a good method for evaluation of antibiotics to be developed in the future.