DNA chip‐based diagnosis of onychomycosis and tinea pedis

Abstract

Summary Background and objectives Onychomycosis (OM) and tinea pedis (TP) are common fungal infections. Currently, diagnosis is based on direct microscopy and culture that have a low to moderate sensitivity and/or require up to 3–4 weeks until results are obtained. PCR techniques have emerged for the diagnosis of fungal infections, but little is known about their sensitivity and specificity in diagnosing. Here, we compared the diagnostic value of a DNA‐chip technology, that detects 56 fungal pathogens, in a single‐center prospective diagnostic study with microscopy and culture in suspected OM/TP. Patients and methods Microscopy, culture and DNA microarray assays were performed on scraping material from patients with suspected OM (n = 67) or TP (n = 73). To test whether swabs can be used as an alternative for scraping, PCR yields were compared in a further 13 patients with OM and 11 patients with TP. Results DNA microarrays had the highest sensitivity. Combination of DNA‐chip technology with microscopy further increased the sensitivity, and results from this combined laboratory diagnosis can be obtained within 24 hours. Comparison of sampling techniques (scraping, dry or wet swab) for DNA‐chip assays showed similar results in suspected OM or TP. Conclusions DNA‐chip technology shows high sensitivity for OM and TP diagnosis, especially when combined with microscopy.

Risk factors and sequelae of epidermolysis bullosa acquisita: A propensity-matched global study in 1,344 patients

“…Because EBA is such a rare disease, we believe that implementation of preventive measures based on the identification of risk factors is, for the most part, impracticable. For example, the identified EBA risk factors dermatophytosis and candidiasis are common diseases ( 26 ). The effort to screen for EBA in these patient populations would not justify the potential benefit.…”

Tinea pedis: an updated review

“…More recently, a DNA-chip assay of the clinical specimen has been developed that allows rapid diagnosis of tinea pedis. 86 In the DNA-chip assay, fungal DNA is amplified by using multiplex polymerase chain reaction with subsequent determination by hybridization on a microarray chip. 86 The DNA-chip assay has a high sensitivity (90.7%).…”

“… 86 In the DNA-chip assay, fungal DNA is amplified by using multiplex polymerase chain reaction with subsequent determination by hybridization on a microarray chip. 86 The DNA-chip assay has a high sensitivity (90.7%). 86 The sensitivity can be further increased to 96.3% by factoring results from microscopic examination of KOH wet-mount preparation or direct immunofluorescence microscopy.…”

Dermatophyte Infections Worldwide: Increase in Incidence and Associated Antifungal Resistance

“…In addition, morphological interspecies differentiation can be difficult in some cases such as T. indotineae, T. mentagrophytes, and T. interdigitale, and in general, requires great experience for accurate identification [95,96]. Molecular diagnostic methods, on the other hand, are becoming a more preferable option, as they can provide quicker and more accurate results [97]. Although this may require special training and advanced equipment, the benefits of utilizing such techniques outweigh this hurdle.…”

“…Several methods have been used in this regard including polymerase chain reaction (PCR) based on internal transcribed spacer (ITS) sequencing, real-time PCR, DNA microarray, and next-generation sequencing [98]. Currently, studies have shown that the best accuracy can be obtained by using both conventional and molecular techniques [97]. Thus, incorporating molecular techniques into routine diagnosis of dermatophytosis can help in overcoming the limitations of the traditional methods.…”