Antifungal susceptibility pattern of dermatophytosis: Need of the hour for antifungal stewardship and policy

Abstract

Background: There has been increase in cases of Dermatophytosis in recent past with emergence of antifungal resistant strains due to inappropriate use of antifungals and poor antifungal policy. There is limited data in literature on antifungal susceptibility testing (AFST). The present study determines the profile and AFST of dermatophytosis.Methods and materials: A prospective study was conducted on patients with superficial fungal infections over a period of 11 months (October 2018 to August 2019). Skin scrapings, hair, and nail clippings were processed by standard fungal culture methods. AFST was performed by using E-test strips (HiMedia) of fluconazole, itraconazole and terbinafine on Sabouraud's Dextrose Agar plates and interpreted according to CLSI (M38A).Results: A total of 29 dermatophytes were isolated from 115 (skin = 63, Nail = 43, scales = 12, Hair = 7) samples (positivity = 25.2%). Out of 29 culture positive patients, 20 presented as tinea corporis, 4 as tinea cruris, 2 as tinea capitis, 1 as tinea incognito and 3 as onychomycosis. T. tonsurans was the most common dermatophyte, 42% (N=12), followed by T. rubrum, 35% (N = 10), T. mentagrophytes, 17% (N = 5) and M. canis, 3% (N=1) and T. megninii, 3% (N=1). AFST of all 29 isolates revealed that 25 isolates showed MIC in susceptible range for itraconazole (0.023 to 0.75 mcg/ml), while, one isolate of T. rubrum and one of T. tonsurans showed higher MICs. Two isolates of T. tonsurans showed lower MICs for itraconazole (0.023mcg/ml.). For terbinafine, (0.002-0.008mcg/ml), 18 isolates showed higher MICs. For fluconazole (range 0.5-4 mcg/ml) only four isolates showed MIC in range while rest 25 showed higher MICs (>256mcg/ml) .The results were communicated to the dermatologists and appropriate changes were made in patient's therapy. Conclusion:The emergence of drug-resistant dermatophytes highlights the need of AFST, antifungal stewardship and development of strong antifungal policy to aid clinicians for instituting appropriate antifungals empirically and to change, if needed, after antifungal sensitivity testing results become available.

Tinea Incognito

“…The initial type of immune response might be different in some individuals. 11 The emergence of antifungal resistance 12,13 might be a factor as well. For cases where fungal infections were suspected and not responding to topical or systemic antifungals, with the addition of low yield of fungal cultures, in some institutions this can lead to misdiagnosing and mismanagement of tineas with topical or systemic immunosuppressants with subsequent TI.…”

No evidence of resistance to itraconazole in a prospective real-world trial of dermatomycosis in India

“…Oral fluconazole, griseofulvin, itraconazole and terbinafine have been used extensively. Itraconazole has remained an important treatment choice for superficial fungal infections and has shown its clinical value in India due to increasing resistance to other antifungals [18][19][20], atypical and unusual presentations of dermatophytosis [21] and the Trichophyton mentagrophytes pandemic in recent years [4,22]. Cases of treatment failures have also been reported with itraconazole, though not linked to anti-fungal resistance [8,20,23].…”