New molecular tools in the diagnosis of superficial fungal infections

Laboratory diagnosis is in a process of major change, with the rapid development of techniques that rely on the application of new scientific skills that provide more accurate and faster confirmation of the presence of infection. This chapter describes the evolution of molecular methods for use in dermatology and their current status. Although many of the techniques that have been published use different detection systems, the evidence shows that there is a growing consensus on the best ways forward. For instance, in dermatophytosis polymerase chain reaction (PCR)-based methods, such as real-time PCR, and detection of changes in the internally transcribed spacer regions are proving to be the most suitable for the detection of different species. Diagnostic application for detection of Candida infection has largely focused on systemic disease, although methods for the diagnosis of vaginal candidosis have been evaluated. It is difficult to separate diagnosis from the other benefits of molecular methodologies in mycology, such as their use in promoting our understanding of the pathogenesis and epidemiology of these diseases. A new gene-based taxonomy has also been necessary. These changes provide a challenge to the clinical dermatologist, because there is still an important task that relies on clinical expertise in relating the presence of molecular fragments of each organism to the presence of infection.