Onychomycosis in Diabetes Mellitus Patients: In Vitro Susceptibility Testing of Four Antifungal Drugs Against Fungal Isolates

Abstract

Introduction: Despite recent advances in the development of antifungal drugs, onychomycosis is still difficult to treat. It negatively affects the quality of life of affected patients. Antifungal susceptibility testing may provide insight into the use of appropriate antifungal medications, thus improving patients' care. 

Objectives: The study aimed to compare the in-vitro susceptibility of fungal isolates' sensitivity patterns against four antifungal drugs among diabetic and non-diabetic patients with onychomycosis. 

Methodology: This cross-sectional study was conducted at the Sub-Department of Dermatology, University of Nigeria Teaching Hospital, (UNTH) Ituku-Ozalla, Enugu, Nigeria. Single colony isolates from clinically suspected cases of onychomycosis among diabetics and non-diabetics were used for the antifungal susceptibility. The inoculum was streaked on Muller Hinton 2% glucose/ methylene blue agar and four commercially prepared available drugs (HIMEDIA, India), namely Fluconazole (25 μg), Itraconazole (30 μg), Terbinafine (e-test 0.002-32 μg) and Voriconazole (1 μg) were applied. The data was analyzed using the IBM Statistical Package for Social Science (version 25).

Results: A total of 276 isolates but single colonies were 217: non-dermatophyte moulds 94, dermatophytes 84, and candida species 39, and were tested against the four antifungal discs. Voriconazole had the highest diameter of inhibition against the three classes of pathogenic fungi among the DM participants (73.9%-100%) and was found to be highly statistically significant (P-value < 0.002).

CONCLUSION: Because of this, voriconazole may be recommended for diabetics with recalcitrant cases, while itraconazole, terbinafine, and fluconazole may be used as empirical treatment of dermatophytes, non-dermatophyte moulds, and yeasts.

KEYWORDS: Onychomycosis, Diabetes Mellitus, Antifungal Susceptibility Testing.