Mycologic ForumMolecular diagnosis of endemic and invasive mycoses: Advances and challengesDiagnóstico molecular de las micosis endémicas e invasivas: avances y retos
Section snippets
Challenges for molecular fungal diagnostic assays
To understand the challenges associated with any molecular diagnostic assay, one needs to understand the incidence and the pathology of the mycoses and the impact on the sample selection for the procedure (blood, serum, plasma, corporal fluids, or biopsy material, either fresh or paraffin embedded), and to carefully evaluate the basic steps of the molecular assay: first, nucleic acid extraction, second, selection of the fungal target(s) and third, amplification method.33, 68 While it is
Nucleic acid based diagnostics for invasive aspergillosis
The amplification of Aspergillus DNA by PCR has been described since the early 1990s, and many studies on the topic have been published. However, as mentioned earlier, protocols vary widely with respect to the PCR assays used, sample target and DNA extraction methods, and this variability makes it very difficult to compare the different “in house” methods developed through the years.20, 22, 33, 68 There are only a few standardized assays that are commercially available. They include LightCycler
Nucleic acid based diagnostics for invasive candidiasis
To date, a variety of nucleic based approaches have been studied for the diagnosis of IC, using a wide range of DNA extraction methods, primers and amplification and measurement approaches, and varied results have been reported for sensitivity (33.3% up to 100%) and specificity (greater than 75% with the exception of some nested PCR assays); see review by Kourkoumpetis et al.,33 PPVs are also extremely variable, with most of the studies reporting PPVs of approximately 50%. Of importance, NPVs
Nucleic acid based diagnostics for endemic mycoses
Several molecular methods have been described for the diagnosis of endemic and systemic mycoses including histoplasmosis, paracoccidioidomycosis, blastomycosis, and coccidioidomycosis. However, all PCR assays have been developed as “in-house” methods and have not been yet established as regular diagnostic tools, there is so far no nucleic acid assay commercially available for use in clinical samples, and the existing assays have not yet been fully standardized and validated by multi-centric
Conclusion
Molecular diagnostics brings many challenges to laboratories and clinicians. Rapid and accurate identification to the genus and species levels of fungal pathogens is crucial for correct management of fungal infections. Better understanding of the strengths and weaknesses of currently available diagnostic tools, and further strategies devised to best implement them either individually or in combination, would greatly improve early and accurate diagnosis of endemic and invasive fungal diseases
Conflict of interest
The author declares no conflict of interest.
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2018, Medical Mycology Case ReportsCitation Excerpt :Serological tests to detect Aspergillus-specific antibodies have not been reliable [6,9,10]. Once the mycotic infection is detected, culture and identification is required but can still remain challenging [11]. Treatment with systemic fungal agents has traditionally been poorly successful.
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2016, Journal of Equine Veterinary ScienceCitation Excerpt :Among the most used are the ITS region (internal transcribed spacer) of ribosomal DNA (rDNA) [99–102], followed by DNA sequencing for the identification of the fungal species. However, DNA sequencing-based techniques are not very useful in routine diagnostic laboratories, as they are costly and time demanding [103]. Other specific targets of each fungal genus have also been successfully explored.