SPECIFIC INFECTIOUS DISEASES PRODUCED BY COCCI 215 



Streptococcus pneumonias 



Synonyms. Pneumococcus; Diplococcus pneumonia; Diplo- 

 coccus lanceolatus; Streptococcus pneumonice; Micrococcus pneu- 

 monice; Micrococcus lanceolatus. 



Disease Produced. Pneumonia in man, and probably some 

 animals, particularly the horse. 



Sternberg, in 1880, described this organism from normal 

 sputum, but Frankel, in 1885, first definitely associated the organ- 

 ism with croupous pneumonia. Considerable difficulty early 

 arose, due to the confusion of two distinct organisms; namely, 

 the form under consideration with the pneumobacillus of Fried- 

 lander. A somewhat similar organism, possibly a gram-negative 

 variety of this form, has been 

 found by Mayer associated with 

 pneumonia in the horse. 



Distribution. Throughout 

 the world, in diseased and 

 healthy individuals. 



Morphology and Staining. 

 Usually occurs in twos, more 

 rarely in chains of four or six, 

 spherical or more generally flat- 

 tened at the point of contact, 

 and with opposite side some- 

 what elongated and pointed, 

 whence the name, lanceolatus. 

 Capsules may be demonstrated 



in the body, but do not appear in culture-media except in 

 serum broth. It stains readily with ordinary anilin dyes, and is 

 gram-positive. There is some doubt as to whether the organism 

 is a Micrococcus or a Streptococcus. The occurrence of chain- 

 formation and lack of any other grouping would make the latter 

 more probable. 



Isolation and Cultural Characters. The organism may in some 

 cases be isolated from the blood directly in pure cultures. It 

 is most readily obtained from the sputum by animal passage. 

 Growth occurs on most laboratory media except potato. Growth 

 is never luxuriant, the organism developing as discrete, transparent, 



Fig. 90. Streptococcus pneumonice 

 in pure culture (Weichselbaum) (Kolle 

 and Wassermann). 



