Antifungal Susceptibility of Candida Species Isolated from Cancer Patients with Oral Lesions Undergoing Chemotherapy

Oral candidiasis is the most common opportunistic infection of the oral cavity in patients undergoing chemotherapy. Identification of Candida species and the corresponding susceptibility to antifungal agents can be helpful in the management of cancer patients.
The purpose of this study was to determine the susceptibility patterns of Candida species against 3 antifungal agents and define clinical practice guidelines for the prevention and treatment of oral candidiasis in cancer patients.
A total of 12 positive samples of oral lesions caused by Candida species were isolated from patients undergoing chemotherapy through direct examination and culture on CHROMagar Candida medium. Stock cultures were grown on sabouraud dextrose agar and DNA extracts. Then, polymerase chain reaction (PCR) was performed and the products were sequenced. The microdilution method was applied at different concentrations of fluconazole, amphotericin B, and nystatin. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each species were compared.
The species distribution of Candida isolates was as follows: C. albicans, 6 (50%); C. krusei, 3 (25%); and C. tropicalis, 3 (25%). The male-to-female ratio was 8:4, and the mean age of cancer patients was 51.25 years (range, 25-81 years). Overall, 100% and 83% of C. albicans were resistant to nystatin and fluconazole, respectively. All Candida species showed the lowest and highest resistance to amphotericin B (8.3%) and nystatin (66.7%), respectively.
DNA sequencing showed that C. albicans is the most commonly identified species in the oral cavity of cancer patients. Amphotericin B, compared to fluconazole and nystatin, is a more suitable antifungal drug for oral candidiasis. Oral hygiene involves dental cleaning, and management of poor denture hygiene and xerostomia can be helpful in eliminating Candida species in patients undergoing chemotherapy.