BACILLUS PYOCYANEUS 229 



obtained in about 97 per cent of all positive cases of the disease. 

 The test is conducted as described in Chapter XIII, save that 

 several strains of B. mallei are used together as an antigen. 



All attempts to produce artificial immunity against glanders 

 have so far been unsuccessful. 



BACILLUS PYOCYANEUS 



The blue green color occasionally seen in the purulent dis- 

 charge of wounds of long standing was shown by Gessard, in 1882, 

 to be due to a chromogenic bacillus to which was given the name 

 B. pyocyaneus. 



Morphology and Staining. The organism is a slender rod 

 from 2 to 6 /i long and 0.3 to 1 p broad ; it possesses a single 

 flagellum at one end and is actively motile. It stains with the 

 ordinary aniline dyes, is Gram negative, and does not form spores. 



Cultivation. The bacillus is an aerobeand facultative anaerobe. 

 It grows readily on all artificial culture media and gives to most of 

 them a bright green color. On gelatin growth rapidly develops, 

 imparting to the medium the characteristic hue; liquefaction 

 commences about twenty-four hours after inoculation and soon 

 the entire medium becomes fluid. On agar a wrinkled yellowish 

 white surface growth appears, the agar itself being a brilliant 

 green. In broth a heavy pellicle is formed and indol is produced ; 

 milk becomes curdled and shows an alkaline reaction. 



The bacillus produces two pigments : one a fluorescent green 

 which is soluble in water but not in chloroform and which is 

 common to many bacteria ; and another, pyocyanin, which is of 

 a blue color and soluble in chloroform. Pigment production is 

 most abundant in the presence of oxygen and at a temperature 

 of about 22 C. 



In addition to the ferment causing the liquefaction of gelatin 

 another enzyme, pyocyanose, is produced, which acts on albumin 

 and is able to dissolve bacteria. It has been applied locally in 

 cases of diphtheria. The results, however, have not been markedly 

 beneficial. 



