Comparison among Different Culture Media for the Detection of Dermatophytes

Dermatophytes are a group of closely related fungi that have the capacity of invading the keratinized tissue of human to produce infections known as dermatophytosis which is commonly referred to as ringworm. Other than routine microscopy, different culture media are available for the detection of dermatophytes from patient's specimen. This cross sectional study was designed to evaluate the outcome of three different culture media and microscopy for the detection of dermatophytes from clinical samples. Skin, hair and nail samples from 84 clinically suspected cases of dermatophytosis who attended at OPD of Dermatology Department, Sylhet MAG Osmani Medical College Hospital, Sylhet, Bangladesh from July 2014 to June 2015 were screened by direct microscopic examination using potassium hydroxide (KOH) mount. All the samples were inoculated for culture in Sabouraud's Dextrose Agar (SDA), Dermatophytes Test medium (DTM) and Sabouraud's Cycloheximide Chloramphenicol Agar (SCCA). The percentage of samples positive by microscopy was 37.5%, whereas the rate of positivity by culture was 47.6% which showed that culture was more sensitive than microscopy for the diagnosis of dermatophytosis. The efficiency of SDA and SCCA was found to be almost equal. There was no statistically significant difference between SDA and DTM in primary isolation of dermatophytes, though isolation rate was slightly higher in DTM. Though direct examination by microscopy is an efficient screening technique, culture should be done for accurate diagnosis. As DTM is easy to evaluate even without handling the growth of culture in the laboratory, it is recommended to use as screening medium for the detection of dermatophytes.