An Efficient Workflow for Fungal Nucleic Acid Detection in Sputum

Area of Science:

• Medical Microbiology
• Molecular Diagnostics
• Infectious Diseases

Background:

• Respiratory fungal infections present diagnostic challenges due to vague symptoms and limitations of traditional methods.
• Accurate and timely diagnosis is crucial for effective treatment and management of these infections.

Purpose of the Study:

• To establish an integrated, rapid workflow for the detection of three common pathogenic fungi responsible for respiratory infections.
• To optimize nucleic acid extraction and develop a multiplex real-time quantitative PCR (qPCR) assay for enhanced diagnostic capabilities.

Main Methods:

• An optimized high-salt lysis method was employed for high-purity nucleic acid extraction.
• A TaqMan-based multiplex real-time qPCR system was developed and optimized for specificity, sensitivity, and reproducibility.
• Clinical validation was performed on sputum samples, comparing results with conventional culture methods.

Main Results:

• The high-salt lysis method demonstrated comparable or superior performance to commercial kits for nucleic acid extraction.
• The multiplex qPCR assay achieved high specificity, sensitivity, and reproducibility, with detection limits as low as 10 CFU/mL for certain fungi.
• Clinical validation showed high agreement with culture, and the assay successfully identified a low-load infection missed by conventional culture.

Conclusions:

• The integrated workflow provides a rapid, sensitive, and specific method for detecting respiratory fungal infections.
• This approach holds significant potential for improving clinical diagnosis and patient management of fungal respiratory diseases.