Preliminary report on a typhoid bacteriophage

Abstract

I would like to report briefly on a lytic principle isolated by the d'Herelle technique from the stool of a typhoid convalescent, kindly sent to me by the Research Laboratory of the Health Department. A small particle of feces was emulsified in broth and incubated overnight. The next day about twice the volume of broth was added and the emulsion was centrifuged and filtered through a Berkfeld. The original filtrate was both inhibitory and lytic, that is, a small amount of the filtrate added to a tube of broth would, in spite of heavy inoculation with the homologous typhoid strain, prevent growth, and young turbid broth cultures became transparent on the addition of small quantities of the filtrate. The lytic principle could then be transmitted in series from both the inhibited and the dissolved cultures.

The lytic principle thus obtained corresponds, for the most part, to those described by d'Herelle. The action is non-specific. It acts on Shiga and Mt. Desert dysentery cultures, as well as on the homologous strain of typhoid and on other typhoid strains. It has no action on the strains of Para A and B that I have tried, and I have not undertaken any experiments to see whether the lytic principle could become acclimatized to these organisms as described by d'Herelle. It also has no action on B. Coli communis, or communior. It does not seem to dissolve or inhibit Gram positive organisms such as the pneumococcus.

It is fairly thermostable. It is not destroyed by a temperature of 70° C. for 30 minutes. It loses its activity, however, after an exposure at 75° C. for 30 minutes. The lytic principle does not maintain its activity for any length of time in sterile broth, and cannot be transmitted in series in this medium.