Discrimination between Candida albicans and Candida dubliniensis isolated from HIV-positive patients by using commercial method in comparison with PCR assay

摘要

Nineteen clinical isolates of Candida albicans and C. 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 degreesC on Sabouraud-dextrose agar as well as on CHROMagar Candida, assimilation of D-Xylose and methyl U-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 for C. dubliniensis. Six clinical isolates were confirmed to be C. dubliniensis, remaining 13 strains were determined as C. 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 between C. albicans and C. dubliniensis we recommend the combination of primo-cultivation on CHROMagar, followed by germ-tube test and PCR.