Candida infections of diabetic foot ulcers

Abstract

histopathologic diagnosis, microbiologic diagnosis SUMMARY The aims of the study were to determine the incidence of Candida infections of diabetic foot ulcers diagnosed by classic microbiologic and histopathologic methods, to study the influence of coexistent interdigital yeast colonization and dermatophytosis of one or both feet on the incidence of fungal ulcer infections, to propose the criteria for diagnosing fungal ulcer infections, and to describe the effect of Candida species on the clinical presentation of infected foot ulcers and treatment outcome. Over a 3-year period, we identified 22 of 509 diabetic outpatients with Candida foot ulcer infections confirmed by microbiologic and histopathologic methods. These infections had developed in chronically infected ulcers (from eighth week onward, in thirteenth week on an average), with C. parapsilosis as the most common causative agent of infection. Mixed (fungal-bacterial) infections were found twice as often as pure fungal infections, and mixed infections correlated with more severe underlying foot infections. In almost two thirds of the patients, without the help of antifungal therapy, the infected foot tissue had to be amputated. Coexistent interdigital dermatophytosis could not be found in any of the patients. In half of the patients no simultaneous interdigital colonization with yeasts could be found in either foot. In conclusion, it should be noted that the incidence of Candida infections of diabetic foot ulcers is low (4.3%), the histopathologic and mycologic analyses of ulcer tissue are complementary methods for diagnosing fungal foot ulcer infections, and interdigital colonization with yeasts and dermatophytosis of either foot does not correlate with the frequency of Candida ulcer infections.