Further Studies on Staphylococcus Bacteriophage

Abstract

A Staphylococcus bacteriophage in pure state was obtained by extracting for 48 hrs. before filtration organisms scraped from massive cultures. Comparison of water and salts in varying strengths showed M/1000 K2HPO4 solution to give the most potent extract. Addition of K2HPO4 to the watery extract increased its potency slightly but less notably than when organisms were extracted directly. Comparison of acid and basic phosphates of Na and K showed best results with alkaline salts of either. Alkaline solutions were universally more active than acid, showing the sensitiveness of pure bacteriophage to changes in pH. Salt concentrations of more than M/100 were destructive to bacteriophage unaffected at M/1000. Activity decreased inversely with valence of anion or cation. It was impossible to precipitate bacteriophage from pure solution by alcohol or acetone, although they readily precipitated it from broth. Chloroform was found to be a suitable agent for sterilizing the solution without destroying the lytic principle. Collodion sacs made with 60-40 ether alcohol solvent withheld bacteriophage. More permeable sacs allowed rapid diffusion.