Superficial fungal infections in 102 renal transplant recipients: a case-control study.

BACKGROUND: Renal transplant recipients are predisposed to superficial fungal infections caused by graft-preserving immunosuppressive therapy. Reports have documented a wide range of prevalence rates for superficial fungal infections in this patient group.

OBJECTIVE: The aim of this study was to determine the prevalence and clinical and mycological features of superficial fungal infections in renal transplant recipients at our center.

METHODS: One hundred two consecutively registered renal transplant recipients (34 women, 68 men) and 88 healthy age- and sex-matched persons acting as controls (30 women, 58 men) underwent screening for the presence of superficial fungal infection. Skin scrapings and swabs were obtained from the dorsum of the tongue, upper part of the back, toe webs, and any suspicious lesions. Nail clippings were also collected. All samples were examined by direct microscopy and were stained with calcofluor white. The samples were cultured in Sabouraud dextrose agar, mycobiotic agar, and dermatophyte test medium. Candida species were identified on the basis of germ-tube production, spore formation in cornmeal agar, and results of biochemical testing. Dermatophytes were identified on the basis of colonial and microscopic morphologic features in conjunction with results of physiologic evaluation (in vitro hair perforation test, urease activity, temperature tolerance test, and nutritional test).

RESULTS: Sixty-five (63.7%) of the 102 renal transplant recipients had cutaneous-oral candidiasis, dermatophytosis, or pityriasis versicolor, whereas only 27 (30.7%) of controls had fungal infection. Pityriasis versicolor was the most common fungal infection in the patient group (36.3%), followed by cutaneous-oral candidiasis (25.5%), onychomycosis (12.7%), and fungal toe-web infection (11.8%). Pityriasis versicolor and oral candidiasis were significantly more common among the renal transplant recipients, whereas the frequency of dermatophytosis in patients and controls was similar. Candida albicans was the main agent responsible for oral candidiasis, and Trichophyton rubrum was the most common dermatophyte isolated. Analysis showed that age, sex, and duration of immunosuppression did not significantly affect the prevalence of superficial fungal infection. Cyclosporine treatment and azathioprine therapy were identified as independent risk factors for superficial fungal disease.

CONCLUSIONS: The prevalence of opportunistic infections with Pityrosporum ovale and C albicans is increased among renal transplant recipients, probably owing to the immunosuppressed state of this patient population. However, renal transplant recipients are not at increased risk of dermatophytosis.