284 A MANUAL OF BACTERIOLOGY 



Bacillus pyocyaneus [Pseudomonas pyocyanea] 



This is the organism found in green and blue pus, and 

 it also occurs on the surface of the body. Its presence in 

 wounds greatly retards healing, and occasionally a general 

 toxaemia may result from it. It has been met with in 

 otitis media and in the green pus of the pleural and peri- 

 cardial cavities. It is a slender bacillus measuring 3 to 

 4 fji, is frequently united in pairs and forms filaments. It 

 is actively motile, does not form spores, and is aerobic 

 and facultatively anaerobic. It does not stain by Gram's 

 method. On gelatin it grows freely with rapid liquefac- 

 tion, a greenish, fluorescent colour developing in the 

 liquid, and whitish flocculi of growth sink to the bottom. 

 On agar a whitish, moist layer develops, and the medium 

 is stained a greenish or bluish colour. On potato the 

 growth is dirty brown or sometimes greenish. 



Milk is coagulated, and a greenish colour develops. 

 Broth becomes turbid, and there is a slight film formation 

 with a yellowish -green colour. Oxygen is necessary for the 

 development of the pigment, which is generally a mixture 

 of a blue pigment, pyocyanin, and a yellow one, pyoxan- 

 those. Pyocyanin (C 14 H 14 N 2 0) is said to be an anthra- 

 cine derivative ; it is soluble in chloroform, and on oxida- 

 tion yields pyoxanthose. Gessard describes sixteen races 

 of the organism. 1 



Subcutaneous inoculation of a small amount of cul- 

 ture produces a local abscess ; larger amounts cause 

 oadema with purulent infiltration of the tissues and death. 

 Animals can be vaccinated by means of small quantities 

 of living cultures or by sterilised cultures. Sterilised 

 cultures will prevent infection (experimentally) by anthrax 

 if used early that is to say, if an animal be inoculated 

 with anthrax, and shortly afterwards injected with a 



1 Ann. de Vlnst. Pasteur, vol. xxxiv, 1920, p. 88, 



