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Pathological studies in experimental Candida endocarditis
Abstract:
Mycotic endocarditis was produced in rabbits by indwelling intracardiac catheters filled with a suspension of Candida albicans. Grossly, cardiac lesions consisted of massive fungoid valvular vegetations and/or "sleeve thrombi" surrounding the catheter. Microscopically, platelet-fibrin aggregates were observed to be loosely attached to the valvular cusps. With time, the vegetations became organized and more firmly attached against the endocardium. Also observed was a heavy neutrophylic collar often containing Candida cells which infiltrate the subendothelial tissues of the valvular cusps. Sterile endocardial lesions were produced by retained catheters. The lesions consisted of discrete, glistening, hemispherical nodules in the right heart; and similar elevated plaques on the mural endocardium of the left ventricle. Microscopically, these lesions consisted of fibrous connective tissues devoid of inflammatory cells. The lesions in the left ventricle were more extensive, extending into the myocardium.
Insights
This study demonstrates how Candida albicans causes mycotic endocarditis in rabbits using catheters. It details the resulting cardiac lesions and sterile endocardial damage from retained catheters.
Area of Science:
- Cardiology
- Mycology
- Pathology
Background:
- Catheter-associated infections pose a significant clinical challenge.
- Fungal endocarditis, particularly Candida albicans, is a serious complication.
Purpose of the Study:
- To investigate the pathological changes associated with Candida albicans-induced mycotic endocarditis in a rabbit model.
- To differentiate fungal endocardial lesions from sterile lesions caused by indwelling catheters.
Main Methods:
- Indwelling intracardiac catheters filled with Candida albicans suspension were used to induce mycotic endocarditis in rabbits.
- Control rabbits had sterile catheters inserted to create sterile endocardial lesions.
- Gross and microscopic pathological examinations were performed on cardiac tissues.
Main Results:
- Candida albicans induced massive fungoid valvular vegetations and sleeve thrombi around catheters.
- Microscopically, platelet-fibrin aggregates, neutrophylic collars with Candida cells, and subendothelial infiltration were observed.
- Sterile endocardial lesions presented as nodules and plaques composed of fibrous connective tissue without inflammatory cells.
Conclusions:
- Candida albicans forms characteristic vegetations and inflammatory responses in mycotic endocarditis.
- Retained catheters alone can induce sterile, fibrotic endocardial lesions.
- This model effectively differentiates fungal from sterile catheter-induced cardiac pathology.