B. Pyocyaneus as a “Carrier” of B. Coli Bacteriophage

Abstract

The phenomenon here reported was first observed in the course of an unsuccessful attempt to discover among a number of specimens of B. coli bacteriophage one that would be active upon B. pyocyaneus. Of 25 filtrates showing marked lysis of one or more strains of B. coli none could be demonstrated to have any lytic power for any of the 7 strains of B. pyocyaneus tested. The bacteriophage specimens were obtained from the following sources: sewage 4; urine 7; feces 15; pus 2; unknown source 1. The phages were tested on the pyocyaneus cultures both as fresh filtrates and after their lytic power for B. coli had been materially enhanced by repeated passage. Neither clearing of young broth cultures nor plaque formation could be demonstrated with any of the strains of B. pyocyaneus.

An attempt was then made with one bacteriophage specimen to bring about pyocyaneus lysis by serial passages upon cultures of the latter organism. A filtrate having marked lytic activity on several strains of B. coli was chosen for this test and its activity was brought to a maximum by a number of passages upon a strain of B. coli, S 1. This coli strain was isolated from a case of pyelitis, belonged to the slow lactose-fermenting group, gave gas on saccharose and marked hemolysis on blood agar plates. One one-hundred-millionth (10^-8) cc. of the lytic filtrate produced complete lysis of a young broth culture in less than 18 hours and, spread upon agar, gave numerous plaques.

Three pyocyaneus strains were used in the test. These all gave the typical abundant growth on agar with the characteristic blue-green pigments and funnel shaped gelatin liquefaction. There was a striking difference in the fermentation reactions of the 3 strains.