Comparative Effects of Sulfapyridine and Sulfanilamide in Type II Pneumococcic Infection of Mice

While sulfapyridine is somewhat more potent than sulfanilamide in the treatment of Type II pneumococcic infection in mice, it does not cure the animals, but only delays death. Untreated mice survived the infection for 1 day. Twenty-four percent of sulfanilamide-treated animals lived 2 days, while about an equal number of sulfapyridine-treated animals, namely 26%, survived 4 days. The superiority of sulfapyridine over sulfanilamide is only in the delay of death by 2 days. Similar experiments were made in Types I and III pneumococcic infection, and the results obtained were about the same as in Type II. In view of the reported good results observed with sulfapyridine in the treatment of pneumonia, our findings in experimental pneumococcic infection in mice are less encouraging than in human infection.