Comparison of Dermatophyte PCR Kit with Conventional Methods for Detection of Dermatophytes in Skin Specimens

Abstract

The laboratory diagnosis of dermatophytosis is usually based on direct microscopic examination and culturing of clinical specimens. A commercial polymerase chain reaction kit (Dermatophyte PCR) has had favorable results when used for detection of dermatophytes and identification of Trichophyton rubrum in nail specimens. This study investigated the efficacy of the Dermatophyte PCR kit for detecting dermatophytosis in 191 hair or skin specimens from patients with suspected dermatophytosis. PCR was positive for 37 % of samples, whereas 31 and 39 % of the specimens were positive by culturing and direct microscopy, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value for PCR analysis were 83, 84, 71, and 91 %, respectively. The sensitivity of the PCR test was higher in specimens obtained from skin (88 %) than in those obtained from hair (58 %), while the specificity remained almost the same (84 and 86 % for skin and hair, respectively). Our results show that the Dermatophyte PCR kit is a promising diagnostic tool for detection of dermatophytosis in skin samples, providing clinicians with a rapid diagnosis.

Development and Evaluation of a Novel Real-Time PCR for Pan-Dermatophyte Detection in Nail Specimens

“…The DNA extraction method used was modified from a previous method [10,19,21]. Consistent with previous studies [22,23], we found that the process of bead beating improves the efficiency of DNA isolation from culture strains (data not shown).…”

Diagnostic performance of molecular and conventional methods for identification of dermatophyte species from clinically infected Arabian horses in Egypt

“…The most significant finding in this study was the rapid identification of dermatophyte species in clinical samples from Arabian horses directly from hair samples utilizing a PCR method. Previous reports have described PCR‐based assays that either identify only one or a few dermatophyte species or are unable to identify dermatophytes to the species level, or are not used directly on clinical material . Some studies have used nested or semi‐nested PCR or double‐round PCR, which are known to have a high risk of contamination .…”

PCR-reverse blot hybridization assay for fast and accurate identification of causative species in superficial fungal infections

“…PCR, a primary technique of DNA‐based analysis, can also be conducted using a real‐time protocol to quantify the relative levels of the transcript and estimate the viability of the sample, and it takes less time than cultures . Moreover, in a study comparing real‐time PCR with conventional diagnostic methods, real‐time PCR provided 100% sensitivity and 82% specificity, and had significantly fewer false‐negative results than conventional diagnostic methods . Real‐time PCR has excellent sensitivity and specificity, but unlike PCR‐REBA, it cannot determine a number of species at the same time.…”

“…3,14 Moreover, in a study comparing real-time PCR with conventional diagnostic methods, real-time PCR provided 100% sensitivity and 82% specificity, and had significantly fewer false-negative results than conventional diagnostic methods. 15,16 Real-time PCR has excellent sensitivity and specificity, but unlike PCR-REBA, it cannot determine a number of species at the same time. In vivo reflectance confocal microscopy and the fungal fluores- cence method can be used to diagnose dermatophytic infection, but they require expensive equipment and extensive technical training.…”