P087 A clinicomycological study of dermatophyte infection including antifungal susceptibility testing in patients attending a tertiary care hospital in north-western state of rajasthan

Abstract

 Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectivesTreatment-resistant ermatophytosis caused by Trichophyton rubrum (T. rubrum) or Trichophyton mentagrophytes (T. mentagrophytes)/Trichophyton indotineae have recently emerged as a global public health issue. This phenomenon is spreading, and is particularly important in endemic areas such as India. However, due to lack of focused studies on dermatophyte prevalence, there is paucity of such data from Rajasthan. Hence, for better understanding of the prevalence, antifungal susceptibility, and resistance pattern to enable best empiric treatment the present study was done.Materials & MethodsA total of 100 patients attending Dermatology and Venereology outpatient department during the period of December 2019-October 2020 were enrolled under this prospective study. Samples were subjected to KOH, culture examination, and identified by standard techniques at the mycology section of department of microbiology. Antifungal susceptibility testing was performed by Microbroth dilution as per CLSI guidelines (M38-A2) with the following drug concentration ranges—amphotericin B 0.0313-16 μg/ml; flucytosine 0.125-64 μg/ml, ketoconazole 0.0313-16 μg/ml. Itraconazole and voriconazole 0.0078-4 μg/ml, fluconazole 0.0625-32 μg/ml, caspofungin 0.0313-16 μg/ml and terbinafine 0.0156-8 μg/ml.ResultsAmong 100 clinical samples tested, culture positivity was found to be 63%, including dermatophytes (76.1%), non-dermatophytes molds (19.04%), and yeasts (∼ 4%). Among dermatophytes, T. mentagrophyte was the predominant isolate (33.3%) followed by T. rubrum (29.1%). Most common clinical type was tinea cruris (53%) followed by tinea corporis (23%). Itraconazole and voriconazole were found to be most effective at MIC range of 0.0078-4 μg/ml for T. mentagrophyte and at 0.0078-1 μg/ml for T. rubrum, mostly corroborating with clinical outcome. Itraconazole resistance was highest (57%) in T. rubrum, whereas terbinafine resistance (>0.2 μg/ml) was seen in ∼ 31-37% of these two major species.ConclusionIt is important for clinicians to emphasize upon microbiological diagnosis of dermatophytosis as these infections have many mimics, highlighting the need of confirmation by culture. High prevalence of terbinafine resistance in both T. mentagrophyte and T. rubrum and itraconazole resistance in T. rubrum is of concern and highlights the need to routinely perform antifungal drug susceptibility testing as a necessary adjunct to treatment and for surveillance.