Use of Sulfanilamide in the Treatment of Type XIV Pneumococcus Infections in Mice

Abstract

Rosenthal 1 showed that sulfanilamide (p-aminobenzenesulfonamide), used therapeutically, prolonged the lives of mice infected with 10 to 100 M.L.D. of types I, II, and III pneumococci. Cooper, 2 independently, made a similar finding in type III pneumococcus infections. Similar experiments of our own, which had been in progress prior to these publications, confirmed Cooper's results. This observation suggested the use of such therapy in infections with other types of pneumococci—IV to XXXII—and particularly in those types for which potent antisera are not readily available. The present report concerns experiments with type XIV pneumococci; this organism causes about 16% of all pneumococcus pneumonias in children less than 12 years of age and 2.5% of such pneumonias in persons older than 12 years. 3

A type XIV pneumococcus, freshly isolated from the bloodstream of a patient suffering from bronchopneumonia, was passed through mice until maximal virulence was obtained. This organism was only moderately virulent for mice; 0.5 cc. of a 1–10,000 dilution of an 18-hour broth culture, injected intraäbdominally, invariably killed mice within 48 hours. Forty-eight mice were injected intraäbdominally with 0.5 cc. of a 1–1000 dilution of an 18-hour broth culture of this organism; 8 of these mice were untreated controls. The remaining mice were divided into 5 groups; all received subcutaneous injections of 5 mg. of sulfanilamide∗ (0.5 cc. of a 1% aqueous solution) every 4 hours. This therapy was started 2 hours after infection in group A and 4, 8, 12, and 24 hours after infection in groups B, C, D, and E (Fig. 1).

When treatment was started within 4 hours of the time of infection, all of the mice survived; less protection was afforded when therapy was delayed for 8 and 12 hours although the survival time was prolonged.