Immunological Identification of Fungal Species

On-site detection of Sporothrix globosa using immunoglobulin Y, magnetic separation and loop-mediated isothermal amplification

BACKGROUND

Sporothrix globosa (S. globosa) is an agricultural activity-related but neglected pathogenic fungus responsible for sporotrichosis. Timely detection is crucial for managing and preventing its spread. However, due to the lack of efficient recognition elements for enriching S. globosa, the current approaches for detecting S. globosa are not simple and/or sensitive enough. This hinders their wider application of fast screening.

RESULTS

Herein, we successfully prepared immunoglobulin Y (IgY) targeting S. globosa, and developed a rapid and accurate detection method, improving upon current limited and inadequate detection approaches. Our method combined the use of IgY and loop-mediated isothermal amplification (LAMP) to enhance detection sensitivity and specificity simultaneously. The IgY was fabricated on magnetic beads to specifically concentrate S. globosa in samples, while LAMP amplified the captured target after simple boiling DNA extraction. By using our method, as low as 4.66 × 102 Cells mL-1S. globosa was accurately detected in soil and corn straw samples. We further integrated this assay into a portable toolbox for sample-to-result detection in resource-limited areas. By using this toolbox, we have colorimetrically detected soil and corn straw samples contaminated by S. globosa, suggesting the promising on-site detection potential.

SIGNIFICANCE AND NOVELTY

A new IgY recognizing S. globosa was prepared. Through the combination of IgY enrichment and LAMP amplification, the detection sensitivity and specificity were improved simultaneously. This method eliminated thermal cycling, simplified the operation, and reduced the analysis time. Compared to existing methods, our approach is more suitable for on-site detection and can significantly improve public health responses to sporotrichosis outbreaks.

Identification and production of novel potential pathogen-specific biomarkers for diagnosis of histoplasmosis

IMPORTANCE

Histoplasmosis is considered one of the most important mycoses due to the increasing number of individuals susceptible to develop severe clinical forms, particularly those with HIV/AIDS or receiving immunosuppressive biological therapies, the high mortality rates reported when antifungal treatment is not initiated in a timely manner, and the limitations of conventional diagnostic methods. In this context, there is a clear need to improve the capacity of diagnostic tools to specifically detect the fungal pathogen, regardless of the patient's clinical condition or the presence of other co-infections. The proposed novel pathogen-specific biomarkers have the potential to be used in immunodiagnostic platforms and antifungal treatment monitoring in histoplasmosis. In addition, the bioinformatics strategy used in this study could be applied to identify potential diagnostic biomarkers in other models of fungal infection of public health importance.