Chemotherapeutic Action of Various Forms of Penicillin on Hemolytic Streptococcal Infections in Mice. ∗

Abstract

Summary

The comparative efficacy of 4 forms of penicillin and random samples of “commercial” penicillin has been studied in experimentally-produced hemolytic streptococcal infections in mice. On a unitage basis the relative chemotherapeutic efficacy of penicillin X, G, F and K under the experimental conditions used, was on the order of 500, 100, slightly less than 100, and 60 respectively. On a gravimetric basis, the relative order of efficacy was 270 for X, 100 for G, slightly less than 92 for F and 82 for K. The values for penicillin F were obtained with a preparation which contained impurities, the action of which is not known.

All of the samples of “commercial” penicillin were 3 to 5 times as effective as crystalline penicillin G in protecting the animals against the infection. Moreover, the protective action exerted by these impure penicillins was of the same order regardless of the unitage per mg or the value of the Bacillus subtilis-Staphylococcus aureus differential ratio. The protective power of pure X is as great as that observed following the administration of the impure “commercial” penicillins. As the latter were manufactured by a process which presumably excludes the presence of X, it would not seem that the superiority of the impure penicillins over crystalline G could be attributed to the presence of X in the impure material.