98 BACTERIA AS ANTAGONISTS 



comma cells and in a few seconds rendered inactive such bacterial toxins 

 as that of diphtheria. Since the bacteriolytic action of pyocyanase was in 

 direct proportion to the time of its action and concentration, and in in- 

 verse proportion to the numbers of bacteria acted upon, its enzymatic 

 nature was believed to be substantiated. The preparation withstood 

 heating in flowing steam for 2 hours. 



It has been established that pyocyanase has a lytic effect against the 

 diphtheria organism, streptococci, meningococci, the typhoid organism, 

 pneumococci, P. festis. Vibrio metchnikovi, V. commas and many other 

 bacteria. There has been considerable disagreement, however, concern- 

 ing the chemical nature and therapeutic action of pyocyanase, due 

 largely to the variation in the nature of the preparations obtained. 

 Kramer, for example, has shown (529) that the activity of the sub- 

 stance depends on three factors: nature of strain, not all strains being 

 equally effective} composition of medium, glycerol-containing media 

 being most favorable} and method of extraction of active substance 

 from culture media. The enzymatic nature of pyocyanase was not uni- 

 versally accepted, largely because of the thermostability of the sub- 

 stance, its solubility in organic solvents, and the fact that temperatures 

 of o to 37° C. fail to influence its activity (59, 420, 737). 



Vs. aeruginosa produces, in addition to pyocyanase, a blue pigment, 

 pyocyanin. Both substances possess lytic properties, i : 1,000 dilution of 

 the pigment being able to lyse E. coli in 6 hours. Pyocyanin was said to 

 be more effective in younger cultures, and pyocyanase in older. Pyo- 

 cyanin had a bactericidal action also upon S. hemolyticusy S. albus, S. 

 aureus, C. dl-phtheriae , M. tuberculosis, V. metchnikovi, and the 

 Y-Ruhr bacillus, but not upon P. vulgaris, E. coli, or the typhoid organ- 

 ism. In general, gram-positive bacteria were largely affected. Numer- 

 ous other substances have been isolated from the cells of the organism 

 or from the culture medium of Ps. aeruginosa. It is sufficient to men- 

 tion the pyo-compounds and pyolipic acid. 



In order to test the action of Ps. aeruginosa upon other bacteria, 

 Kramer (529) placed a drop of a suspension of this organism upon a 

 plate inoculated with M. tuberculosis or with V. metchnikovi. In 24 

 hours, a sterile zone surrounded the colony of the antagonist, the width 



