Spectrum of fungi causing onychomycosis in a tertiary care hospital in Bangalore

Introduction: Onychomycosis is a fungal infection of nails caused by dermatophytes, yeasts or non-dermatophyte moulds and represents about 30% of mycotic cutaneous infections. Onychomycosis manifests itself in various forms, notably onychodystrophy, onycholysis, subungual hyperkeratosis, or nail-plate discoloration. The objective of this study was isolation and speciation of various fungi by culture and to determine its prevalence. Materials and Method: The study was conducted from Jan 2014 - June 2016 at a tertiary care hospital, Bangalore. Nail-clipping and subungual debris of clinically suspected patients were subjected to Potassium hydroxide (KOH) preparation. Culture was done on Sabouraud’s dextrose agar (SDA) media. Species identification was done by colony character, pigment production, Lactophenol cotton blue (LPCB) staining, some special tests like germ tube test, inoculation into chrome agar in case of Candida and slide culture wherever necessary. Result: Out of 400 cases, the KOH preparation was positive for fungal elements in 288 (72%) cases and culture grew fungi in 268 (67%) cases. Among those 268 cases, the infective fungal agents were predominantly dermatophytes (59.7%) and the rest were due to moulds (22.38%) and yeasts (17.91%). Among the different species, Trichophyton rubrum (T. rubrum-37.5%) accounted for the majority of dermatophytes, Fusarium (60%) was the commonest mould and Candida albicans (37.5%) the predominant yeast. Conclusion: Direct microscopy and culture are extremely important in the diagnosis of onychomycosis and dermatophytes are the most common etiological agent in our region. Keywords: Dermatophytes, KOH, LPCB, Onychomycosis