CHAPTER XXIII 



NON-SPECIFIC PYOGENIC BACILLI 



MANY bacilli have been isolated from suppurative infections. 

 Some of these undoubtedly have no causal relationship to the pus- 

 production and are purely saprophytic; others, as the colon bacil- 

 lus, are normally non-pathogenic, but under certain conditions 

 may cause pus-infection; others, as the typhoid bacillus, normally 

 cause specific diseases, but occasionally produce a secondary 

 pyogenic infection, while others are known only from their associa- 

 tion with suppurative processes, and may be termed true pyogenic 

 bacilli. Two organisms belonging to the latter class are worthy 

 of specific mention Bacillus pyocyaneus and B. pyogenes suis. 

 They are grouped here solely because of their pyogenic properties, 

 and not on account of any relationships existing between them. 

 Their only common characteristics are their shape and ability to 

 incite suppuration. Our knowledge of the B. pyogenes suis is 

 unsatisfactory. It probably should be grouped with some other 

 forms, possibly with the Bacillus pseudotuberculosis. 



Bacillus pyocyaneus 



Synonyms. Pseudomonas pyocyanea; Ps. aeruginosa; bacillus 

 of green or blue-green pus in man and animals. 



Gessard, in 1882, described the Bacillus pyocyaneus from blue- 

 green pus. Since that time it has been isolated and studied by 

 numerous investigators, both in Europe and America. 



Distribution. This organism has been isolated from the feces 

 of man and animals, from sewage and surface waters, from the 

 soil, and from air and dust. It is usually saprophytic or com- 

 mensal in its growth, and is only rarely pathogenic. 



Morphology and Staining. B. pyocyaneus is a slender rod with 

 rounded ends, about 0.6 by 2.6 u or smaller, usually single, rarely 

 in chains of 2 to 6 individuals. It is motile by means of a single 

 terminal flagellum. No spores or capsules are produced. It 

 stains readily by the ordinary anilin dyes, and is gram-negative. 



228 



