Diagnostic Performance of Direct Microscopic Techniques and Culture Media for Fungal Isolates from Hair Specimens

Abstract

Objective: To compare the diagnostic performance of direct microscopic techniques and culture media for detecting fungal isolates in hair specimens.
Study Design:  Cross-sectional study.
Place and Duration of Study: The study was conducted at the Department of Microbiology, Basic Medical Sciences Institute, Karachi, Pakistan, from January 2021 to June 2021.
Materials and Methods:  A total of 207 hair specimens were collected from the patients with superficial mycoses of the scalp. The specimens were collected under aseptic techniques using clean glass slides and forceps which were processed for Potassium hydroxide mount and Calcofluor white staining. The mycological cultures were performed on a Dermatophyte test medium and Sabouraud Dextrose agar with and without antibiotics. The data was recorded and analyzed on SPSS version 21. The frequencies, percentages, means, and ratios were calculated using Descriptive statistics. The association between variables were analyzed by the Chi-square test and kappa index.
Results: Potassium hydroxide mount revealed fungal spores and hyphae in 154(74.3%) specimens, while Calcofluor white staining showed fungal elements in 179(86.5%) specimens. Out of 207 specimens, 106(51.2%) were culture positive and 101(48.8%) were declared culture negative. Out of culture-positive specimens, dermatophytes were yielded in 61(57.5%) and non-dermatophytes in 45(42.5%) specimens. Among all culture media, the highest number of dermatophytes was yielded by plain Sabouraud dextrose agar (59; 96.5%), followed by dermatophyte test medium (55; 90%), and Sabouraud dextrose agar with antibiotics (54; 90.1%). On the contrary, the primary isolation of non-dermatophytes on the plain was Sabouraud dextrose agar s 32(71.1%), Sabouraud dextrose agar with antibiotics 31(68.2%), and dermatophyte test medium 13(28.8%).
Conclusion: In our study, we found Calcofluor white staining technique as the most sensitive method to detect fungal elements from the given hair specimens. For mycological culture, all tested culture media were equally effective for the retrieval of dermatophytes. However, for non-dermatophytes, plain SDA and SDA with antibiotics were found to be better media for isolation.