Bacillus Pyocyaneus, Gessard (1882). 



BACILLUS OF GREEN OR BLUE PUS. 



ORIGIN. In green pus. The color forms on exposure to air. Sev- 

 eral varieties have been described. It is very widely distributed in 

 nature. It has been found on the skin and in the mouth, nose, stoni- 

 ach and intestines. Not infrequently, it is found in the lungs, blood 

 and internal organs of men and animals; in dust, soil and in water. 

 In many respects it resembles the liquefying 1 , fluorescing bacillus. 



FORM. Small narrow rod like that of blue milk. At times 

 almost a coccus. The ends are rounded. It is usually single, may 

 form short threads of 4-6 cells, or even longer, spiral-like filaments. 



MOTILITY. Actively motile. Single polar whip. 



SPORULATION. Has not been observed. 



ANILIN DYES. It stains easily; also by Gram's method. 



GROWTH. Is rapid and abundant. Oxygen is necessary to the 

 formation of pigment. 



Plates. On gelatin plates a green fluorescing pigment develops quite early. The 

 surface colonies at first tend to spread; then produce funnel-shaped liquefactions. The deep 

 colonies appear as round, coarsely granular masses with serrated borders. They are yel- 

 lowish and may show radial markings. 



Stab culture. In. gelatin tubes funnel-shaped or cylindrical liquefaction results. The 

 upper layer is at first green but later the entire contents are colored. In very old cultures 

 the color changes to a brownish black. A scum forms on the surface. 



Streak culture. On agar a moist, slimy, yellowish growth develops and the medium 

 itself becomes bright green. When very old the agar becomes dark colored and the growth 

 has a peculiar scaly, metallic appearance. On potato a yellowish green or brownish slimy 

 growth forms. 



Milk. Grayish yellow spots form on the surface; the casein is precipitated (rennet 

 action); subsequently it is peptomzed with production of ammonia. 



Bouillon. Becomes very cloudy and a heavy deposit forms. A thick white scum 

 forms on the surface. The upper layer of the liquid is greenish. Indol is produced. 



OXYGEN REQUIREMENTS. Is a facultative anaerobe. No growth 

 under mica plates, but can grow in the body. The presence of air is 

 necessary to the production of the pigment, pyocyanin (p. 116). 



TEMPERATURE. Grows at ordinary temperature; best at 37. 



BEHAVIOR TO GKLATIN. Liquefies rapidly. Under anaerobic con- 

 ditions this property may be lost. 



AEROGENESIS. Produces a characteristic aromatic odor. Hydro- 

 gen sulphide, mercaptan, butyric acid, hydrogen, carbonic acid, etc. 



ATTENUATION. Artificial cultures diminish in virulence. More- 

 over, variation in pigment production will be met with. Even, color- 

 less varieties have been obtained. 



IMMUNITY. Injection of small amounts of the culture, or of steri- 

 lized cultures induces immunity. 



PATHOGENESIS. Subcutaneous injection, in guinea-pigs and rab- 

 bits, of about 1 c.c. of a fresh bouillon culture produces a rapidly 

 spreading edema, purulent inflammation and death. Incase of recov- 

 ery a local abscess forms. Intraperitoneal injections produce puru- 

 lent peritonitis and death. Bacilli are numerous in the tissues, blood, 

 organs, etc. Small amounts produce less marked results and recovery. 

 Virulent cultures will kill rabbits in about 2 days in a dose of T foj- c.c. 

 or less, subcutaneously. Cure of animals infected with anthrax by 

 inoculation with B. pyocyaneus. This bacillus was formerly consid- 

 ered as a harmless form, accidentally introduced into wounds. While, 

 in general, it is not markedly pathogenic for man, yet there are times 

 when it may take on toxic properties. 



DIAGNOSIS. It is to be distinguished from the ordinary fluorescing 

 bacteria. When an agar culture of B. pyocyaneus is whipped up 

 with chloroform, the latter becomes blue. Isolated colonies in deep 

 gelatin liquefy, whereas those of the fluorescing bacilli do not. 



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