PCR-Based Microarray Enhances Diagnosis of Culture-Negative Biopsied Tissue in Patients with Invasive Mold...

Area of Science:

• Medical Mycology
• Molecular Diagnostics
• Infectious Diseases

Background:

• Invasive mold infections (IMIs) pose diagnostic challenges, particularly in immunocompromised patients.
• Current diagnostic methods like culture and histology have limitations in sensitivity and speed.
• Oligonucleotide microarrays combined with PCR offer a potential rapid detection method for fungal pathogens.

Purpose of the Study:

• To evaluate the performance of a fungal polymerase chain reaction (PCR) coupled with an oligonucleotide microarray assay for diagnosing IMIs from tissue samples.
• To compare the diagnostic accuracy of the PCR/microarray method against conventional culture and histology.
• To assess the clinical utility of this molecular diagnostic approach in difficult-to-diagnose cases.

Main Methods:

• DNA extraction from biopsied tissue samples.
• Nested PCR amplification of the internal transcribed spacer (ITS) region of fungal DNA.
• Hybridization of amplicons with an in-house oligonucleotide microarray containing probes for various mold species.
• Comparison of PCR/microarray results with clinical diagnosis, culture, and histology.

Main Results:

• The study analyzed 80 clinical samples from 74 patients with suspected IMIs.
• The PCR/microarray test demonstrated a sensitivity of 70% and specificity of 95.7% for diagnosing IMIs.
• Compared to culture (10% sensitivity) and histology (40% sensitivity), the PCR/microarray provided more sensitive results.
• Positive PCR/microarray findings influenced clinical management, leading to antifungal therapy initiation in some cases.

Conclusions:

• The fungal PCR/microarray assay is a valuable tool for the rapid and precise diagnosis of IMIs, especially when conventional methods are inconclusive.
• Combining PCR/microarray with fungal culture and histology enhances diagnostic accuracy for challenging IMI cases.
• This molecular approach can provide crucial microbiological evidence to support clinical decision-making in suspected invasive fungal infections.