High prevalence of non-albicans yeasts and detection of anti-fungal resistance in the oral flora of patients with advanced cancer

Abstract

Oral fungal infections frequently develop in individuals with advanced cancer. This study examined the oral mycological flora of 207 patients receiving palliative care for advanced malignant disease. Demographic details and a clinical history were documented from each participant. A tongue swab was collected and cultured on CHROMAgar Candida (CHROMAgar Paris, France). All yeasts were identified by germ tube test, API ID 32C profiles and, for Candida dubliniensis, by species-specific PCR. Susceptibility to fluconazole and itraconazole was determined by a broth microdilution assay according to the National Committee for Clinical Laboratory Standards (NCCLS). At time of sampling, 54 (26%) of the 207 subjects had clinical evidence of a fungal infection and yeasts were isolated from 139 (67%) individuals. In total, 194 yeasts were isolated, of which 95 (49%) were Candida albicans. There was a high prevalence of Candidia glabrata (47 isolates) of which 34 (72%) were resistant to both fluconazole and itraconazole. All nine isolates of C. dubliniensis recovered were susceptible to both azoles. No relationship was established between anti-fungal usage in the preceding three months and the presence of azole resistant yeasts. This study of patients with advanced cancer has demonstrated a high incidence of oral colonization with non-C. albicans yeasts, many of which had reduced susceptibility to fluconazole and itraconazole. The role of improved oral care regimes and novel anti-fungal drugs merits further attention, to reduce the occurrence of fungal infection in these patients.