CHAPTER XVI 

 PNEUMOBACILLUS OR BACILLUS OF FRIEDLANDER 



BACILLUS MUCOSUS CAPSULATUS 



Bacillus Friedlander is widely distributed in nature, it occurs in air, water, 

 soil, dust, milk, feces, saliva and sputum; in the mouth and sputum of some 

 healthy people and in tissue attacked by this organism. 



Morphology. The pneumobacillus is about i to 4 /A long and 0.5 to i.o n 

 broad, has rounded ends and is surrounded by a distinct capsule. This capsule 

 is apparent when organisms removed from tissue are observed; after cultivation 

 on media the capsule may disappear. Pneumobacilli are arranged singly, in 

 pairs and in chains. When in chains the capsules often merge as though one 

 capsule enclosed the chain. This bacillus is not motile. It stains with all the 

 usual stains and is Gram negative. Special stains are required to tint the 

 capsule. In preparations stained by any of the ordinary methods the un- 

 stained capsule appears as a light, colorless zone surrounding the pigmented 

 bacillus. 



Growth. The pneumobacillus grows well on all the ordinary media at 

 temperatures between i5C. and 40C. Slightly acid, neutral or faintly alkaline 

 media will do, but a slightly acid reaction is most favorable. Pneumobacillus 

 is an aerobic and facultative anaerobic organism. Bouillon shows growth in 

 24 to 36 hours; it is clouded, a whitish pellicle forms on the surface and later a 

 stringy whitish precipitate forms. 



Gelatin stabs incubated at room temperature show a whitish growth in 48 

 hours. It follows the line of the stab and gradually extends over the surface, 

 giving a tack-shaped growth. A few small gas bubbles may appear along 

 the stab ; the gelatin is not liquefied. 



Surface cultures on gelatin show round, raised, grayish-white colonies in 

 2 or 3 days. 



Agar. In 24 to 36 hours a confluent, moist, white, tenacious growth covers 

 the surface. On serum agar and LoefHer's medium growth is the same as on 

 agar. 



Milk is usually coagulated, rapidly by some strains and slowly by others; 

 occasionally pneumobacilli are encountered, which do not coagulate milk, or 

 at least fail until subcultured. 



Indol is not formed. Some pneumobacilli ferment all the sugars; another 

 group ferments all the sugars except lactose, and a third group ferments all 

 sugars except saccharose. 



The pneumobacillus does not form spores. 



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