Ground red hot pepper agar in the isolation of yeasts of Candida spp.

The purpose of this study was to investigate and determine the value of a novel, simple and inexpensive selective medium for isolation of yeasts of Candida spp. - ground red hot pepper agar (GRHP). The study compared GRHP and Sabouraud dextrose agar (SDA), an insufficiently selective medium routinely used for primary isolation of yeasts. The comparison was based on qualitative and quantitative characterisation of growth of 25 bacterial strains, measurement of growth of 22 yeast strains and testing on clinical specimens. Qualitative tests on bacteria showed either significantly less growth on GRHP than on SDA, or no growth on GRHP. Quantitative tests confirmed these results; the number of colonies of all tested bacterial species and strains on GRHP was significantly lower than on SDA. With regard to the isolation of Candida spp., GRHP had the same properties as SDA. Statistical analysis showed no significant differences in the growth of Candida spp. and strains on the two media. All these results were confirmed by tests on clinical material. The results clearly show that GRHP agar is an economical medium for the isolation of yeasts of Candida spp., with excellent selectivity.