NON-SPECIFIC PYOGENIC BACILLI 229 



Isolation and Culture. This organism is readily isolated by 

 plating out pus which contains it, as the colonies are quite charac- 

 teristic on account of the green pigment which they diffuse. 

 It grows readily on all the common laboratory media. Upon 

 agar and gelatin plates the thin, poorly denned colonies are charac- 

 terized by the fluorescent pigment surrounding them. Upon 

 slant agar the color diffuses until the whole of the medium is a 

 light green, then a darker blue-green, and finally a brown or brown- 

 red. Gelatin is rapidly liquefied. Bouillon is clouded, a pellicle 

 forms, and the fluorescent pigment diffuses from the top downward. 

 Potatoes support a slimy growth 

 and turn green, then brown. 

 Milk is coagulated by a rennet- 

 like enzyme, and the curd pep- 

 tonized. 



Physiology. This organism 

 is preferably an aerobe, and 

 grows most luxuriantly in the 

 presence of oxygen, but growth 

 will continue under anaerobic 

 conditions. Proteolytic fer- 

 ments which will digest gelatin, 



rig. 97. Bacillus pyocyaneus (Kolle 

 fibrin, and casein are produced. and Wassermann). 



Two pigments are usually 



formed one green and fluorescent (fluorescin), the other (pyo- 

 cyanin) bluish. Pigment is not produced in the absence of 

 oxygen. In old cultures the pigments become yellow or brown. 

 Autolytic disintegration of the cells takes place in old cultures. 

 Mucin, a compound made up of a protein and a carbohydrate, 

 has been found present in cultures. To this may be ascribed its 

 slimy consistency on agar or even in bouillon. The organism is 

 resistant to desiccation. 



Pathogenesis. Experimental Evidence. Injection of cultures 

 of B. pyocyaneus subcutaneously into the guinea-pig or rabbit 

 causes rapidly spreading edema, suppuration, septicemia, and death 

 within a day or two. Not all cultures are equally pathogenic. 



Character of Infection Produced. The B. pyocyaneus is usually 

 a secondary invader, although in man it has been found causing 



