Isolation, identification and antifungal susceptibility of dermatophytes from clinical specimens in a tertiary care hospital in South Kerala

Abstract

Dermatophtyosis is common, more prevalent in tropical and subtropical countries including India. Though not life threatening it can cause great discomfort, especially in immunocompromised conditions. In the last few years a number of new less toxic antifungal drugs have become available for clinical use. Lack of clinical response may occur in 20%.125 clinically suspected cases of dermatophytosis were studied.The samples were subjected to direct microscopy and culture. Identification of the causative pathogen was done by performing slide culture, lacto phenol cotton blue mount, hair perforation tests and urease tests. In this study we evaluated the efficacy of seven antifungal medications using CLSI broth microdilution method (M38-A). The antifungals used were sertaconazole, terbinafine, griseofulvin, fluconazole, itraconazole, voriconazole and amphotericin B.Out of 125 samples, dermatophytosis manifested clinically more in the age group of 21-30 yrs. In our study, KOH positivity rate was 60.8% and culture positivity rate was 32%. Dermatophytosis was more common in females. Tinea corporis was the most common lesion (54.4%) followed by Tinea cruris (25.6%), Tinea pedis (8%), Tinea unguium(7.2%) and Tinea faciei (0.8%). was the commonest aetiological agent (50%) followed by (35%), (7.5%), (5%) and (2.5%). The range of their minimum inhibitory concentration endpoint by broth microdilution technique for the seven antifungal drugs were as follows, sertoconazole <0.06-4 μg/ml , griseofulvin 0.25-1 μg/ml, terbinafine <0.06-2 μg/ml, voriconazole 0.06-0.5 μg/ml, itraconazole <0.06-1 μg/ml, fluconazole 2-8 μg/ml and amphotericin B 2-8 μg/ml. This study gives an insight about the aetiological agents of dermatophytosis in this part of South Kerala, India. Both direct microscopy and culture are important tools for diagnosis of the superficial fungal infections. Majority of strains in the study were inhibited by relatively low concentration of the antifungals tested.