Evaluation of different DNA extraction methods based on steel-bullet beating for molecular diagnosis of onychomycosis

Novel Discoveries and Clinical Advancements for Treating Onychomycosis: A Mechanistic Insight

Onychomycosis continues to be the most challenging disease condition for pharmaceutical scientists to develop an effective drug delivery system. Treatment challenges lie in incomplete cure and high relapse rate. Present compilation provides cumulative information on pathophysiology, diagnostic techniques, and conventional treatment strategies to manage onychomycosis. Novel technologies developed for successful delivery of antifungal molecules are also discussed in brief. Multidirectional information offered by this article also unlocks the panoramic view of leading patented technologies and clinical trials. The obtained clinical landscape recommends the use of advanced technology driven approaches, as a promising way-out for treatment of onychomycosis. Collectively, present review warrants the application of novel technologies for the successful management of onychomycosis. This review will assist readers to envision a better understanding about the technologies available for combating onychomycosis. We also trust that these contributions address and certainly will encourage the design and development of nanocarriers-based delivery vehicles for effective management of onychomycosis.

Candida spp. DNA Extraction in the Age of Molecular Diagnosis

The standard procedure for the detection of candidemia is blood culture, a method that might require 3-5 days for a positive result. Compared with culturing, molecular diagnosis techniques can provide faster diagnosis. The current paper aimed to present the main strengths and constraints of current molecular techniques for Candida spp. DNA extraction, analyzing their efficiency from a time, price, and ease of usage point of view. A comprehensive search was conducted using the PubMed NIH database for peer-reviewed full-text articles published before October 2022. The studies provided adequate data on the diagnosis of the infection with the Candida spp. DNA extraction is a relevant step in yielding pure qualitative DNA to be amplified in molecular diagnostic techniques. The most used fungal DNA extraction strategies are: mechanical (bead beating, ultrasonication, steel-bullet beating), enzymatic (proteinase K, lysozyme, lyticase), and chemical extraction (formic acid, liquid nitrogen, ammonium chloride). More clinical studies are needed to formulate adequate guidelines for fungal DNA extraction as the current paper highlighted discrepancies in the reported outcome.

Direct molecular analysis of Malassezia species from the clinical samples of patients with pityriasis versicolor

Background and Purpose

Species identification of Malassezia using culture-dependent methods is time-consuming due to their fastidious growth requirements. This study aimed to evaluate a rapid and accurate molecular method in order to diagnose the pityriasis versicolor (PV) and identify Malassezia species from direct clinical samples.

Materials and Methods

Skin scraping or tape samples from patients with PV and healthy volunteers as the control group were collected. Diagnosis of PV was confirmed by direct microscopic examination. The DNA extraction was performed according to the steel-bullet beating method. Polymerase chain reaction-restriction fragment length polymorphism assay using HhaI restriction enzyme was applied for the identification and differentiation of Malassezia species.

Results

The PCR method was able to detect Malassezia in 92.1% of specimens which were also confirmed with microscopic examination. Statistically, a significant association was observed between the results of the two assays (P < 0.001). Moderate agreement was identified between the two methods to diagnose the PV in both populations (Kappa: 0.55). Considering microscopic examination as the gold standard method for confirmation of PV, the sensitivity, specificity, positive predictive value, and negative predictive value values of the PCR assay for recognition of PV were 85%, 75%, 92%, and 60%, respectively. M. globosa and M. restricta were the most prevalent species isolated from patients.

Conclusion

In this study, the two-step molecular method based on the amplification of the D1/D2 domain and digestion of the PCR product by one restriction enzyme was able to diagnose and identify Malassezia directly from clinical samples. Consequently, it can be said that the molecular-based method provides more facilities to identify fastidious species, such as M. restricta.