CHAPTER 5 



BACTERIA AS ANTAGONISTS 



Following the work of Pasteur in 1877 on the antagonistic ef- 

 fects of bacteria against the anthrax organism, considerable attention 

 has been centered upon bacteria as agents possessing antibacterial prop- 

 erties. A systematic study of this phenomenon was first made by Babes 

 in 1885 (155), who demonstrated that this antibacterial action is due 

 to the formation of definite chemical substances. Garre (315) first in- 

 troduced, in 1887, suitable methods, such as the streak test, for demon- 

 strating the antagonistic effect of one organism upon another. The first 

 antibiotic substance, pyocyanase, was isolated in 1 899 by Emmerich and 

 Low (235). 



Freudenreich (298) found in 1888 that when certain bacteria were 

 grown in a liquid medium, the filtrate obtained by passing the culture 

 through a porcelain candle supported the growth of the typhoid or- 

 ganism not at all or only very feebly. Garre (315) observed that Ps. 

 futida inhibited the growth of S. aureus, E. tyfhosa, and Bacillus muco- 

 sus-cafsulatus but not of B. ant hr acts and other bacteria. It was soon 

 reported {S^'i)j however, that B. anthrach was also killed by the 

 Pseudomonas antagonist, whereas the growth of S. aureus and V . 

 comma was only retarded j no effect at all was exerted upon E, typhosa 

 or E. coli. In consequence, the antagonist was claimed to be active 

 against B. anthrach but not against other bacteria. Olitsky (691) con- 

 cluded that Ps. -fluorescens inhibited the growth not only of E. typhosa 

 but also of B. anthracis, V. comma, S. marcescens, and S. aureus. These 

 and other apparently contradictory results were undoubtedly due to 

 differences in the specific nature of the strains of the organisms used by 

 the various investigators and to different methods of cultivation. 



The presence of Ps. fluorescens in sewage was found (551 ) to reduce 

 greatly the period of survival of the typhoid organism. The latter did 

 not develop even in gelatin upon which Ps. fluorescens had previously 

 grown, and it could not be detected in sterile sewage in which the an- 

 tagonist was present for seven days. According to Frost (303), E. ty- 



