Differential growth inhibition as a tool to increase the discriminating power of killer toxin sensitivity in fingerprinting of yeasts.

A panel of 27 cell-free crude killer toxin preparations were used in fingerprinting 45 Saccharomyces cerevisiae and 11 Saccharomyces exiguus strains. The differential sensitivity to different mycocins was evaluated both as binary data matrix (presence-absence of killing effect), and by considering the growth inhibition areas (measured by agar diffusion well bioassay). The first approach gave an individual fingerprinting of 68% of sensitive strains, whereas the second gave a total and reproducible (P<0.01) discrimination of all tested strains.