Bacteriophages in Bacterial Cultures.

Abstract

In carrying out examinations of fecal specimens for the presence of bacteriophage, the 11 strains of Eberthella typhi from the American Type Culture Museum were utilized, together with 14 cultures of other organisms from our own laboratory. It was noted that most of the strains of Eberthella typhi were sensitive to bacteriophage action, but that two cultures appeared to be very resistant. The relative susceptibility of these cultures is shown by results from 39 fecal samples which contained bacteriophage active against one or more typhoid strains. The findings of the third generation against the 11 typhoid strains and 2 strains of Escherichia coli are shown in Table I.

Of the Eb. typhi cultures it is seen that strains 191 and 196 were very resistant to bacteriophage action. As no lysis of Es. coli B71A occurred while B70A was lysed 6 times, it would appear that B71A was relatively resistant.

The resistance of these cultures might be due to the presence of a bacteriophage in the cultures. In testing for the presence of a bacteriophage 12 more cultures were added to the group, making a total of 25. The additional cultures were: 3 species of salmonella, 1 strain Eb. dysenteriae, 1 strain Eb. paradysenteriae, 1 strain Proteus vulgaris, 3 species of staphylococcus, 2 species of Aerobacter.

These organisms were inoculated. into plain broth and incubated for 24 hours. At the end of that time each culture was filtered through separate Berkfelt candles and the filtrates of each tested for activity against all 25 organisms. The test was performed by adding to a tube of plain broth 3/10 cc. of a 6 hour growth of the organism, and adding immediately following, 3/10 cc. of the fiiltrate to be tested.