Analysis of ERG 11 expression in clinical isolates of dermatophytes in patients with resistant Tinea infection.

Abstract

Background: Dermatophytes are keratinophilic groups of microorganisms which invade keratinized tissue. Objective:1 - Isolate and identify the dermatophyte species from samples collected from patients suffering from onychomycosis, tinea corporis and tinea cruris; and perform in vitro microbroth antifungal susceptibility testing. Objective:2 - Further, the expression of Ergosterol 11 (ERG 11) amongst the isolates from responders and non-responders to antifungal treatment was studied by Real-time PCR. Methods & Results: A total of 120 dermatophytosis cases attending a dermatological clinic in a tertiary care hospital were included in the study. Microscopy of KOH mount was positive in 90 isolates while 60 were culture positive. The most common dermatophytes implicated were Trichophyton mentagrophytes (75%) followed by Trichophyton rubrum (25%) which were molecularly confirmed by PCR using the species-specific primer. Higher MIC was detected for fluconazole (10 %), itraconazole (3.33 %), terbinafine (10 %) and griseofulvin (5 %), for T. mentagrophytes and T rubrum, while all strains showed lower MIC for voriconazole and luliconazole. Interpretation & Conclusion: The study observed a predominance of T. mentagrophytes causing chronic dermatophytosis. The rising MIC to terbinafine and griseofulvin among the isolates raises a concern for effective management. The real-time PCR analysis of ERG 11 expression in certain isolates demonstrated up-regulation in patients not responding to treatment as compared to responders, the impending failure of azoles as a line of treatment in dermatophytosis.