PP 3 - Onychomycosis among adults in a Grama Niladhari Division, Anuradhapura, Sri Lanka

Madhuwantha KC, Adhikari AMAC, Gunathilaka MGRSS, Jayaweera JAAS , Department of Microbiology, Faculty of Medicine and Allied Science, Rajarata University of Sri Lanka

Abstract

Introduction

Onychomycosis is a fungal infection of the nails common in warm and humid regions in Sri Lanka, and there is limited local data on its prevalence, aetiology and antifungal susceptibility.

Objectives

To assess the prevalence of onychomycosis among adults in a Grama Niladhari Division, Anuradhapura District, and to identify and determine the antifungal susceptibility of the causative fungal organisms in the study population.

Design, setting, and methods

A descriptive cross-sectional study was conducted among adults residing in a Grama Niladhari Division, Anuradhapura District, Sri Lanka, and laboratory analysis was conducted at the Microbiology Laboratory, Faculty of Medicine and Allied Science, Rajarata University of Sri Lanka from September 30, 2025, to January 31, 2026. Subjects with clinically diagnosed onychomycosis were recruited following consent. Clinical and socio-demographic data were collected via interviewer-administered questionnaires. Nail clippings were evaluated by KOH mount, cultured on Sabouraud Dextrose agar, and incubated at 37°C and 26°C. Identification was done using phenotypic methods. Specimens isolating non-dermatophyte fungi were reevaluated for significance. Antifungal susceptibility testing was performed based on EUCAST AFST, with minimum inhibitory concentration (MIC) determined using the micro-broth dilution method. Data were expressed in measures of central tendency.

Results

Among 44 patients with suspected onychomycosis (58 ±13 years), 35 were females (79.5%) and presented with toenail involvement (84.1%). The point prevalence was 3.8%. Forty KOH mounts (90.9%) were positive for fungal structures. Eighty-two per cent (33) were having positive fungal growth, most commonly yielding dermatophytes and Aspergillus spp. (each 29.5%) followed by Candida spp. (13.6%) and Penicillium spp. (2.3%). Among dermatophytes, Trichophyton spp. (69.3%) were the commonest. A. niger was the commonest Aspergillus spp. isolated (53.8%), followed by A. fumigatus (15.4%) and A. terreus (7.7%). C. krusei accounted for 83.3% of candida infections and was speciated using CHROMagar. All Aspergillus isolates were susceptible to amphotericin B (MIC ≤1 µg/mL), whereas all exhibited resistance to ketoconazole. A. fumigatus (92.1%) was susceptible to itraconazole (MIC ≤1 µg/mL). Among dermatophyte isolates, 92% was sensitive to itraconazole (0.25 ECOFF (mg/L), 15.4% were susceptible to fluconazole (MIC ≤16 µg/mL), but all were resistant to ketoconazole, and 92.3% were having MIC₉₀ ≥2 µg/mL to griseofulvin. All Candida were resistant to amphotericin B, fluconazole, and ketoconazole whereas Penicillium spp. were susceptible to amphotericin B and resistant to ketoconazole.

Conclusions

Onychomycosis was caused mainly by dermatophytes and Aspergillus species. The susceptibility to itraconazole is still high, but increased resistance to other first-generation azoles among dermatophytes, Candida, and non-dermatophyte moulds points to the need to perform routine mycological investigations and antifungal susceptibility testing.