Kidney homogenate, a test medium to determine the inhibitory effect of antimycotics on yeasts

The test procedure described in this paper aims at assessing the effectiveness of antimycotics against yeasts. The inhibitory effect on Candida albicans growth is determined in the presence of kidney homogenate, an in vitro test medium offering fungal growth conditions similar to physiological conditions. The inoculum consists of kidney material from Candida-infected mice. By dilution with kidney material from uninfected mice the initial number of viable particles is standardised. Specimens withdrawn from this inoculum are mixed with different concentrations of the test substance and incubated for 24 hours. The inhibition of fungal growth is assessed on the basis of the number of colony-forming units in comparison with controls to which no test substance was added. The growth phase of C. albicans during incubation in vitro resembles that observed in the kidney in vivo, i.e. besides yeast cells, the fungus produces a great number of pseudomycelia and mycelia. The results of the tests conducted with the top-ranking antimycotics give good evidence of their therapeutic efficacy. The testing of further active substances revealed advantages of the new test model over existing test methods.