Zygomycosis: conventional laboratory diagnosis

Area of Science:

• Medical Mycology
• Pathology

Background:

• Zygomycosis, a serious fungal infection, is primarily caused by fungi in the order Mucorales.
• Accurate diagnosis is crucial for timely and effective treatment.

Purpose of the Study:

• To outline the diagnostic criteria for zygomycosis caused by Mucorales.
• To emphasize the importance of histopathological findings and fungal culture interpretation.

Main Methods:

• Histopathological examination of affected tissues to identify characteristic fungal elements.
• Fungal culture on standard media (e.g., Sabouraud dextrose agar) at 25-30°C.
• Special stains like Gomori methenamine-silver, periodic acid-Schiff, and Calcoflour white.

Main Results:

• Histopathology reveals broad, hyaline, ribbon-like hyphae with wide-angle branching, tissue necrosis, and angioinvasion.
• Mucorales exhibit rapid growth on fungal media.
• Positive cultures from sterile sites or repeated positives from non-sterile sites in high-risk patients are diagnostically significant.

Conclusions:

• Histopathological evidence of tissue invasion is essential for diagnosing zygomycosis.
• Interpretation of fungal cultures requires clinical correlation, especially from non-sterile sites.