Rapid Detection of Dermatophytes in Primary School Children with Tinea Capitis

Fayed, Sahar Mohamad; El- Esawy, Fatma M.

doi:10.21608/ejmm.2019.283190

Rapid Detection of Dermatophytes in Primary School Children with Tinea Capitis

Document Type : New and original researches in the field of Microbiology.

Authors

¹ Department of Clinical and Chemical Pathology, Faculty of Medicine, Banha University, Egypt

² Department of Dermatology and Andrology, Faculty of Medicine, Banha University, Egypt

10.21608/ejmm.2019.283190

Abstract

Background: Tinea capitis is a dermatophyte infection of the scalp, eyebrows and eyelashes. The disease is common among preadolescent children and mainly caused by Trichophyton and Microsporum species. Accurate and rapid identification is challenging as conventional methods are slow and mostly based on morphological characteristics. Objective was to investigate the usefulness of nested polymerase chain reaction (PCR) and Dermatophyte Test Medium (DTM) for rapid, accurate & reliable diagnosis of tinea capitis and to identify the most common causative dermatophytes among primary school children. Methodology One hundred clinical specimens from children pre-diagnosed clinically as tinea capitis were collected and analyzed using conventional mycological methods (culture on SDA and KOH microscopy), culture on DTM and pan-dermatophytes nested PCR. Results 82/100 clinical sample were found positive with pan - dermatophyte nested PCR, followed by culture on DTM which could detect dermatophytes in 78 % of suspected cases. Hyphae and/ or spore structures were observed in 68% of samples with direct KOH microscopy and lastly, dermatophytes were isolated by conventional culture in (56%) of samples. Microsporum canis (42.9%) was the most prevalent strain, followed by T. mentagrophytes (23.2%). There was good agreement between both nested PCR and DTM with direct KOH microscopy and there was moderate agreement between both methods and conventional culture. However, there was very good agreement between the two investigated methods and our data indicated that the two methods yielded higher positivity in less time than conventional methods. Conclusion: By the use of nested PCR, rapid reliable results were achieved within 24 hour in contrast to the 4 weeks incubation required by conventional culture. This technique is not only rapid but also simple and inexpensive in comparison to other molecular methods. DTM is ideal for hospital practice as it can be used as a screening test for detection of dermatophytes but additional testing may be needed for species identification.

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