Discrimination between Candida albicans and Candida dubliniensis Isolated from HIV-Positive Patients by Using Commercial Method in Comparison with PCR Assay

Nineteen clinical isolates ofCandida albicans andC. dubliniensis were isolated from patients (majority of them HIV-positive) in Slovakia, Brazil, Thailand and Japan. Species discrimination was performed by using growth on CHROMagar Candida, commercial biochemical set API 20C AUX, germ-tube test in human serum, growth at 42 and 45°C on Sabouraud-dextrose agar as well as on CHROMagar Candida, assimilation ofd-xylose and methyl α-d-glucoside by glass-tube test, and production of chlamydospores. These tests were completed by PCR using Cd-oligo2/F and Cd-oligo2/R primer pair specific forC. dubliniensis. Six clinical isolates were confirmed to beC. dubliniensis, remaining 13 strains were determined asC. albicans. The use of conventional method showed that the determination is markedly influenced by personal evaluation suggesting the necessity of using the combination of many tests to obtain correct results comparing with accurate and rapid PCR assay. For discrimination betweenC. albicans andC. dubliniensis we recommend the combination of primo-cultivation on CHROMagar, followed by germ-tube test and PCR.