Pneumonia death rate and types of pneumococci in Norway

Abstract

Avery, Chickering, Cole, and Dochez 1 give the death rate of patients with pneumonia not receiving serum treatment in the hospital of the Rockefeller Institute as nearly 30% ; the death rate of type 1 pneumonia they give as 25%, of type 2 as 32^, of type 3 as 45% and of type 4 as 16^. These are hospital figures and consequently probably somewhat higher than the figures for cases outside hospitals. The death rate from pneumonia in Norway is undoubtedly lower than in the United States, and we have made observations on the types of pneumococci in Norway in order to ascertain whether there is any difference in the distribution of the different types in the two countries. We obtained sputum from the hospitals in Christiania and from private practitioners, which we studied according to the accepted technic. Immediately on arrival in the laboratory the sputum is examined as to the various forms of bacteria present; a small particle is then emulsified in broth and injected into the peritoneal cavity of a white mouse; at the same time, a loop of sputum is streaked on the surface of a plate of agar with rabbit blood yc/c. As soon as dead, and usually death occurs within 20 hours, the peritoneal cavity of the mouse is washed out with salt solution and the suspension centrifugated so as to throw down the cells that may be present, and an agglutination test made with serum obtained either from the Rockefeller Institute or from the Health Department of New York City. The serum is used in a dilution of 1: 10, and the results are read immediately or after one hour in a water bath at 37 C. Further identification of the pneumococcus is made according to its growth on the surface of the blood agar, the fermentation of inulin and its solution in bile. According to this technic, 100 cases of typical lobar pneumonia gave 44 cases of type 1, 33 of type 2, 6 of type 3, and 17 of type 4. There is a close correspondence in these results with the results obtained in the United States, type 1 being apparently more prevalent in Norway, but on account of the comparatively small number of cases examined by