Fluconazole Susceptibility and Genotypic Heterogeneity of Oral Candida albicans Colonies from the Patients with Cancer Receiving Chemotherapy in China

AIM: To identify heterogeneity of Candida albicans (C. albicans) isolated from the population with cancer in China by using identification medium, subculture molecular typing, and antifungal susceptibility test. METHODOLOGY: Oral cheek mucosal specimens from 52 cancer patients receiving chemotherapy were cultured on CHROMagar Candida(TM) plates for Candida identification. All the C. albicans colonies on the plates were subcultured and reconfirmed by API20C, then submitted to the antifungal drug susceptibility test with fluconazole and molecular typing using randomly amplified polymorphic DNA-PCR (RAPD) with primers RSD6 and RSD12. RESULTS: 54% (28/52) patients were oral yeast carriage in which C. albicans predominated. More than 7 C. albicans colonies were isolated from each of 12 patients (Group A), while less than 5 colonies were isolated from each of 16 patients (Group B). RSD6 and RSD12 were successful in eliciting 17 (A1-A17) and 2 (B1-B2) genotypes, respectively from among the 205 isolates. The two primers were combined to generate 21 genotypes. The C. albicans isolates obtained from the same patient and episode showed a diversity for fluconazole revealed by MIC(50) and MIC(90). CONCLUSION: The heterogeneity of the C. albicans colonies isolated from the same patients can be detected. C. albicans with varied fluconazole susceptibility and genotypic characteristics may coexist in the same oral Candida population.