[Various ways of standardizing and unifying biological methods of determining the activity of antibiotics].

It was shown possible to use nutrient media containing only salt components and agar-agar for determination of biological activity of tetracyclines (tetracycline, morphocycline, oxytetracycline and chlortetracycline), erythromycin and oleandomycin. A uniform nutrient medium containing ammonium chloride, trisubstituted sodium citrate, disubstituted sodium phosphate and agar-agar was developed. Glucose is added to this medium simultaneously with the test microbe, B. subtilis ATCC 6633. The medium of the above composition provided readily reproducible results.