Sulfapyridine and Sulfanilamide in Experimental Pneumococcal,Meningococcal,Welch Bacillary and Friedländer's Bacillary Infections in Mice. ∗

We 1 , 2 have discussed the comparative therapeutic efficiency of sulfapyridine and sulfanilamide in the treatment of experimental hemolytic streptococcal and Type I pneumococcal infections in mice. These reports were based upon results obtained in mice the origins of

which were unknown. Recently, we have used pure bred mice (strain CF1) whose genetic formula is ccaabb, as test animals for the study of the effects of chemotherapeutic agents upon various types of experimental infections. We believe the use of pure bred mice eliminates the factor of variations in host susceptibility.

In this report we will present data concerning the comparative therapeutic effects of sulfapyridine and sulfanilamide upon experimental infections in mice produced by several types of microörganisms. With the exception of the Welch bacillus and meningococcus, the strains of organisms were virulent for mice in dilutions of 10⁸ to 10⁹, and the meningococcus was made highly virulent by suspension in mucin. The technic of producing these infections has already been described by us. 3 , 4 The data presented in each instance represent the average of several experiments.

As will be noted in Table I, the chemotherapeutic effect of sulfa-pyridine in experimental Types I, II, and III pneumococcal infections in mice is superior to that of sulfanilamide. The results obtained by us are distinctly inferior to those reported by Whitby, 5 but this may be explained by the higher mouse virulence of the strains of pneumococci which we employed and the fact that we used slightly smaller, though more frequently repeated, doses of sulfapyridine.

Little difference was noted in the chemotherapeutic effects of the two compounds in the control of experimental meningococcal or Welch bacillary infections in mice.