Different toenail onychomycosis due to Rhodotorula mucilaginosa and Candida parapsilosis in an immunocompetent young adult

Candida parapsilosis (C. parapsilosis) and Rhodotorula mucilaginosa (R. mucilaginosa) have emerged as a potential pathogen in immunosuppressed hosts; they rarely induce onychomycosis in immunocompetent hosts without assistance from other pathogens. Here we present onychomycosis induced by two strains on different toenails in an immunocompetent young adult. The patient presented with onychomycosis on left and right first toenails due to R. mucilaginosa and C. parapsilosis, respectively. Based on the diagnosis, he had been orally treated with itraconazole 200 twice daily for one week every four weeks that repeated 7 times; however, the toenails did not respond satisfactorily to the treatment. After two months of drug cessation, we confirmed that the two toenails were infected with different fungi. R. mucilaginosa was isolated from the left first toenail, and C. parapsilosis was isolated from the right first toenail. Identifications were confirmed by morphological and cultural characteristics as well as by DNA molecular analysis. After determining in vitro drug susceptibility, the patient was successfully treated with a topical application of ketoconazole cream on the left toenail and oral itraconazole. It is the rare known case of different nails being infected by R. mucilaginosa and C. parapsilosis respectively.