Abstract
Disc diffusion method is a basic method for testing susceptibility of bacteria to antibiotics. The principle consists in placing antibiotic discs onto agar plates that have already been inoculated with selected sample of bacteria.
The plates are then incubated overnight. After incubation, the zones of inhibition surrounding the antibiotic discs can be seen.
In school conditions the nonpathogenic bacteria isolated from environment can be used very well for this test. If teacher chooses antibiotics with different mechanism of effect, students can after the test easily find out that each antibiotic has variously strong effect to one species/strain of bacteria.
This effect depends on metabolism and composition of bacteria. In the same manner the susceptibility of other microorganisms, e.g. yeast or mould, can be tested.
In this case, students can see no inhibition zones on the agar plate and can find out that antibiotics have no effect on yeast or mould. Experiments described in this paper can be used in inquiry-based education tasks.