Ground red hot pepper agar in the isolation and presumptive identification of Cryptococcus neoformans.

The study compared ground red hot pepper agar (GRHP) and Guizotia abyssinica creatinine agar (GACA), a medium routinely used for isolation of Cryptococcus neoformans. In order to confirm the capacity of GRHP to support the Cr. neoformans growth and pigment production, 15 strains were inoculated onto GRHP and GACA. No significant differences in the growth and pigmentation of the tested strains on the two media were noted. As heavily contaminated specimens, 50 samples of pigeon droppings were examined by plating on GRHP and GACA, which resulted in the isolation of 14 and nine Cr. neoformans strains, respectively. The results indicate that GRHP, as a result of its superior selectivity and significant reduction of contaminant growth, provides better conditions than GACA for isolation and presumptive identification of Cr. neoformans from heavily contaminated specimens.

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.