BACILLUS PYOCYANEUS 381 



tion as blue needles. It forms salts 'with acids, and exists as a leuco- 

 base in cultures from which oxygen is excluded. The color changes 

 to a brownish-red in old cultures. 



Enzymes. One of the noteworthy products of Bacillus pyocyaneus 

 is a soluble proteolytic enzyme, a protease, which dissolves gelatin, 

 casein, coagulated blood serum and fibrin. 1 Breymann 2 showed that 

 the bodies of the bacteria, freed from culture media, contained the 

 same or a similar enzyme. Emmerich and Low 3 isolated a proteolytic 

 enzyme, called by them pyocyanase, which possessed the remarkable 

 property of dissolving alien bacteria. This enzyme has been used 

 therapeutically with some success. Whether pyocyanase is identical 

 with the protease mentioned above has never been clearly determined. 



No diastatic enzymes have been detected in cultures of Bacillus 

 pyocyaneus. 4 



Toxins. Wassermann 5 found that filtered cultures of Bacillus 

 pyocyaneus or cultures killed with toluol would kill guinea-pigs when 

 injected intraperitoneally in amounts of 0.2 to 0.5 c.c. The organisms 

 themselves were decidedly less toxic. The toxicity is not attributable 

 to the specific pigment, pyocyanin, but to substances of unknown 

 composition. 



Pathogenesis. Animal. Bacillus pyocyaneus is pathogenic for 

 small laboratory animals, guinea-pigs being the most susceptible. 

 A cubic centimeter or less of an actively growing broth culture intro- 

 duced into the peritoneal cavity causes death within twenty-four hours 

 as a rule. There is edema, leukocytosis, and the peritoneal fluid 

 increased in amount swarms with the bacilli. Rabbits are less sus- 

 ceptible; rats and mice are relatively refractory. The subcutaneous 

 injection of cultures of the organism, especially if the virulence is not 

 great, leads to a chronic, wasting infection which usually terminates 

 fatally. The subcutaneous tissue becomes edematous and necrotic, 

 and ulceration frequently occurs. 



Human. Besides the focal lesions, abscesses, ulcers, otitis media, 

 less commonly liver abscesses, and bronchopneumonia, Bacillus pyo- 

 cyaneus occasionally produces severe gastro-intestinal infection, 

 especially in young children, generalized sepsis, and inflammation of 

 serous surfaces, the pleura, pericardium, and peritoneum. 



1 Jakowski, Ztschr. f. Hyg., 1893, xv, 474; Fermi, Centralbl. f. Bakt., 1891, x, 401; 

 Kendall, Day and Walker, Jour. Am. Chem. Soc., 1914, xxxvi, 1966, and others. 



2 Centralbl. f. Bakt., Orig., 1902, xxxi, 481. 



3 Ztschr. f. Hyg., 1899, xxxi, 1. 



4 Fermi, loc. cit. 6 Ztschr. f. Hyg., 1896, xxii, 263. 



