[Effect of certain factors on the determination of the biological activity of amphotericin B].

Sensitivity of the test-microbe to amphotericin B was studied. It was shown that composition of the nutrient medium, the innoculum amount and preincubation may significantly change the conditions of determination of the test-microbe sensitivity to amphotericin B and affect the accuracy of the microbiological method of determination of the antibiotic activity. The size of the inhibition growth zones of the test-microbe at amphotericin B concentrations within 0.06 to 1000 gamma/ml were measured. The angle of the dose response curve was the least at amphotericin B concentrations within 0.06 to 1.0 gamma/ml. Therefore, they were most suitable for plotting the standard curves. The population growth character of a number of test-cultures was investigated. A new test-culture, i.e., C. scotti Tul-I was proposed as one being most sensitive to amphotericin B, having prolong lag-phase of the population growth, forming even growth and clear inhibition zones.