Evaluation of the efficacy of novel topical antifungal agents against dermatophytes in North India: A prospective study.

Background and purpose: Dermatophytosis, a fungal infection targeting keratinized tissue, is caused by dermatophytes, commonly affecting skin, hair, and nails. Prevalent in tropical regions, such as India, its treatment typically utilizes systemic and topical antifungal medications. Despite ample research on oral antifungals, data on the susceptibility of topical treatments, especially in India, where they are prevalent, remains scarce. This study aimed to investigate the antifungal susceptibility of efinaconazole, tavaborole, luliconazole, and sertaconazole against dermatophytes isolated from cases of dermatophytosis.

Materials and methods: Samples of all the clinically diagnosed cases of dermatophytosis were subjected to microscopy and culture. All 204 dermatophytes, namely Trichophyton rubrum (n=90), Trichophyton mentagrophytes/interdigitale (n=69), Trichophyton tonsurans (n=44), and Epidermophyton floccosum (n=1) were subjected to antifungal susceptibility testing for efinaconazole, tavaborole, sertaconazole, and luliconazole per Clinical Laboratory Standards Institute broth microdilution method (M38-A3).

Results: The minimum inhibitory concentration values for efinaconazole, tavaborole, sertaconazole, and luliconazole were within the ranges of 0.008-0.5, 1-2, 0.128-2, and 0.004-0.008 µg/ml, respectively across all dermatophytes. Epidemiological cutoff values (ECVs) were 0.004 µg/ml for luliconazole and 2 µg/ml for tavaborole for all dermatophytes. Sertaconazole ECVs were 2 µg/ml for T. rubrum and T. mentagrophytes/interdigitale, 0.5 µg/ml for T. tonsurans, and 1 µg/ml for E. floccosum. Tavaborole ECVs for T. mentagrophytes/interdigitale, T. tonsurans, T. rubrum, and E. floccosum were 0.5, 0.5, 0.25, and 0.016 µg/ml, respectively.

Conclusion: The results from the present study on the in vitro performance of newer topical antifungals suggested that they hold significant promise as prospective candidates for advancing the development of new antifungal treatments for dermatophytosis.