Stassano and de Beaufort (1) discovered that the growth of certain phages was inhibited by the presence of citrate in the culture medium, and that this inhibition could be overcome by the addition of calcium salts. Bordet and Renaux (2) investigated a strain of Shiga phage which was unable to lyse the host cells in the presence of citrate or oxalate. This inhibition of lysis could be overcome by calcium or strontium salts.
Andrewes and Elford (3) investigated in some detail a “citrate sensitive” strain of coli phage. The addition of 0.75 per cent citrate to broth prevented multiplication of this phage and lysis of infected host cells. This concentration of citrate did not hinder the growth of uninfected host cells and did not inactivate unadsorbed virus particles. Furthermore, citrate did not inhibit adsorption of virus to host cell. Bacteria which adsorbed phage in the presence of citrate did not lyse, did not liberate phage and were unable to multiply.