Profile of Dermatophytes and Antifungal Susceptibility Pattern: A Cross-sectional Descriptive Study in a Government Setup in Urban South Kerala, India

Introduction: Recently, there has been a change in the spectrum of dermatophytosis, shifting from Trichophyton rubrum, which was previously the most common species, to the more drug- resistant and chronic Trichophyton mentagrophytes. Although there have been several recent studies on dermatophytosis, the majority have focused on clinical presentation and histopathological features. Therefore, a study that focuses on the current trends in species of dermatophytes causing infection and their antifungal susceptibility is the need of the hour. The treatment options can be tailored accordingly and newer options can be considered. Aim: To determine the proportion of different species of dermatophytes affecting patients attending the Dermatology Outpatient Department (OPD) at a tertiary care centre in Kerala and to assess the antifungal susceptibility of the isolates to Fluconazole, Itraconazole and Terbinafine. Materials and Methods: The present study was a cross- sectional descriptive study, conducted over a period of one year at the Department of Microbiology at Government Medical College, Thiruvananthapuram Kerala, India. Data collection for the study commenced in July 2018 and concluded in June 2019. The study included all patients attending the dermatology OPD with clinically suspected dermatophytosis during the study period. Specimens of skin, hair and nails were collected. Direct examination was performed using 10% Potassium Hydroxide (KOH) for skin and hair samples and 40% KOH for nail samples. Identification was achieved through culture on Sabouraud’s Dextrose Agar (SDA) and Dermatophyte Test Medium (DTM). Antifungal susceptibility testing was conducted using Broth Microdilution testing (BMD). Results: A total of 270 samples were collected. Of these, 53 (19.6%) were culture positive. Among the isolates, 40 (75.47%) were T. mentagrophytes, 7 (13.21%) were T. rubrum and only 6 (11.32%) were Microsporum gypseum. For T. mentagrophytes, antifungal susceptibility testing revealed the Minimum Inhibitory Concentration (MIC) ranges of 1-8 μg/mL, 0.031-0.25 μg/mL and 0.031-0.5 μg/mL for Fluconazole, Itraconazole and Terbinafine, respectively. Other species also exhibited a similar pattern of susceptibility. Conclusions: In the present study, T. mentagrophytes was found to be the predominant species, followed by T. rubrum. Itraconazole was identified as the most effective drug according to antifungal susceptibility testing.