Epidemiological and Microbiological Study of Onychomycosis

Abstract

Introduction: Onychomycosis is a common fungal infection of nail. It may be caused by dermatophytes, non-dermatophytic moulds or yeasts involving nail bed, nail plate or matrix of nail. As the fungi show variable susceptibility to antifungal drugs and treatment requires long duration of antifungal therapy, so it’s prevalence as well as proper laboratory diagnosis and antifungal susceptibility testing is essential for effective therapy. Aim: To find the prevalence of onychomycosis with demography along with various aetiology and the suitable antifungal drugs used for treatment. Materials and Methods: For this prospective study, over a period of two years a total of 300 nail samples were processed in the Department of Microbiology at IMS and SUM Hospital, Bhubaneswar, Odisha, India. The wet mount for microscopic examination was prepared using 20% Potassium Hydroxide (KOH) and examined after overnight incubation. Culture was done in duplicate in Sabouraud’s Dextrose Agar (SDA) tubes; one with actidione and another without it and both were incubated at 25°C in Biological Oxygen Demand (BOD) incubator. Culture tubes growing yeasts were further subjected to speciation by germ tube test, culture on Chromogenic (CHROM) agar and on cornmeal agar. In-vitro antifungal susceptibility testing was performed against Candida species using disc diffusion method on Muller Hinton agar. Chi-square test was used for statistical analysis of the results. Results: Onychomycosis can affect a wide age group though seen commonly at 31-40 years equally in both male and females. Fingernail infection was observed mostly in female cases. It was caused by Candida species (66%), moulds (24%) and dermatophytes (10%) and out of Candida sp. C.albicans was the main culprit. Although all the Candida strains were susceptible to amphotericin B, still some of them showed resistance to the commonly used antifungals like fluconazole and itraconazole. Conclusion:Candida albicans was the most common aetiological agent which contributed for onychomycosis and showed a variable resistance pattern to the commonly used antifungals. Proper laboratory diagnosis and selection of antifungal drug is essential prior to institution of therapy for successful treatment of this disease.