Effectiveness of Sabouraud’s Dextrose Agar and Dermatophyte Test Medium in Detection of Candidiasis and Dermatophytosis in Superficial Skin Lesion

Abstract

Introduction: As time evolves fungal infections have increased its prevalence. Among the fungal infections, superficial fungal infections are the most common type. They can be either chronic or recurrent, therefore simple incidence figures are not the most useful means of understanding the burden of disease. Aim: Isolation and identification of pathogenic fungi from clinically suspected cases of dermatophytosis and candidiasis of skin, also to compare two media used in isolation of the fungus. Materials and Methods: A cross-sectional study was conducted over a period of one year, clinically suspected cases of dermatophyte infection and candidiasis who attended the Outpatient Department of Dermatology and Venereology Government Medical College, Thrissur, Kerala, India, were included randomly in the study. Sample size was taken as 150. Samples were collected from clinically suspected cases of dermatophytic infections and candidiasis of skin and was transported to the Microbiology Department in sterile bottles. Direct examination under KOH (Potassium hydroxide) solution was done. Culture of these samples on Sabouraud’s Dextrose Agar (SDA) with chloramphenicol/gentamycin and Dermatophyte Test Medium (DTM) was analysed. Statistical analysis was done using Statistical Package for the Social Sciences (SPSS) software. Results: Trichophyton mentagrophytes was the commonest isolate 57%, followed by Trichophyton rubrum 27%. Out of six clinically suspected cases of candidiasis, no organism was isolated in the cultures. Almost all dermatophytes isolated were grown in DTM within one week of incubation except Trichophyton rubrum which appeared in the second week, while in SDA only 31% of isolates were grown. Direct smear positivity was found in 95% of the cases, while culture positivity was 45%. All isolates were grown in DTM while 31% were grown in SDA. Conclusion: Trichophyton mentagrophytes was the commonest species isolated. The next common isolate was Trichophyton rubrum. DTM was more useful as a screening medium as opposed SDA as identification medium and the isolation is more rapid.