The in vivo Action of Staphylococcus Bacteriophage in Presence of Staphylococcus Antitoxin

In a previous report it was shown, as it has been by others, that normal rabbit serum in broth inhibits the action of staphylococcus bacteriophage on staphylococci. However, when rabbit serum, immune to staphylococcus toxin was used in the place of normal serum, the bacteriophage remained active and subcultures taken from the higher concentrations of bacteriophage were sterile. This rinding suggested that a combination of staphylococcus antitoxin and bacteriophage might be an efficient therapeutic agent in the treatment of staphylococcus infections. The results of such therapy, which will be reported elsewhere in detail, were discouraging. However, an effect was obtained which seems to show an in vivo action that parallels the previously observed in vitro action. Nineteen rabbits were injected in the right marginal ear vein with 1 cc per kilo of a 48 hour broth culture of Staphylococcus aureus, strain Fs. Blood cultures were obtained from the left marginal ear vein 24 hours later. Six rabbits were then injected in the right ear vein with staphylococcus antitoxin (10 cc.) and bacteriophage (2 cc). Six rabbits were injected with bacteriophage alone (2 cc). The bacteriophage was active against strain Fs in dilutions of 1 x 10-9. The remaining 7 rabbits were kept as controls. This procedure was repeated daily until the 5th day when all of the treated animals, except one treated with bacteriophage alone, were dead. A similar mortality occurred in the untreated animals. Three of the animals treated with bacteriophage and antitoxin and 4 of the rabbits treated with bacteriophage alone were alive 72 hours after the injection of the bacteria. The blood cultures taken at this time and shown in the photograph were typical of the results obtained.