Beef Blood as a Source for Antistaphylococcal Substances.

Various beef tissues such as brain, spleen, heart, kidney, and liver have been shown to be potential sources of antistaphylococcal factors (Nutini and Lynch, J. Exptl. Med. 84:247, 1946; J. Bacteriol. 52:681, 1946; J. Pharmacol. Exptl. Therap. 90:313, 1947; Berger et al., Nature 179:588, 1957). We now wish to report that a similar substance was found in beef blood. Zil'ber and Yakobson (Zh. Mikrobiol. Epidemiol. i Immunobiol. 12:3, 1946) isolated the antibiotic erythrin from the blood of various mammals and found it to have antibacterial effect both in vivo and in vitro. Fresh beef blood, obtained from a local abattoir the filtrate was deproteinized and prepared for assay by the procedure outlined for fraction A. In addition, a separate batch of whole defibrinated blood was deproteinized directly by the addition of 95% ethanol until an alcoholic concentration of 80% was reached. The deproteinized extract was evaporated on a water bath, and the residue was redissolved in distilled water to give an approximate dry weight of 100 mg/ml, neutralized, and sterilized as above. Fractions A and B were assayed prophylactically against a penicillin-resistant strain of Staphylococcus aureus (Columbus 9347). The experimental mice, derived from Rockland