Ultrastructure of Candida parapsilosis endocarditis

Area of Science:

• Mycology
• Medical Microbiology
• Biomaterials Science

Background:

• Candida parapsilosis is a significant cause of fungal endocarditis, particularly in patients with prosthetic heart valves.
• Vegetation formation on bioprosthetic valves is a hallmark of infective endocarditis, leading to serious complications such as systemic embolization.

Purpose of the Study:

• To elucidate the ultrastructural characteristics of Candida parapsilosis vegetations on porcine bioprosthetic valves.
• To correlate the structural features of the vegetations with the clinical complication of large emboli in Candida endocarditis.

Main Methods:

• Light microscopy was employed to examine the overall structure of the vegetations.
• Scanning electron microscopy (SEM) was used to visualize the surface morphology and cellular arrangement.
• Transmission electron microscopy (TEM) provided high-resolution details of the intercellular matrix and cellular interactions.

Main Results:

• SEM revealed a "mossy" amorphous surface with C. parapsilosis cells embedded within a flocculent or fibrillar matrix.
• Cracked vegetation areas exposed loosely adherent C. parapsilosis cells.
• TEM demonstrated a compact intercellular matrix and evidence of hyphal invasion into the valvular tissue.

Conclusions:

• The presence of a loose matrix binding large clumps of C. parapsilosis cells is a key factor contributing to the frequent occurrence of large emboli.
• Understanding the structural basis of vegetation formation is crucial for developing strategies to prevent or treat Candida endocarditis complications.