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Modifying cerebral candidiasis by altering the infectious entry route
Abstract:
Diffuse leptomeningitis did not occur in healthy adult male Wistar rats with transient candidemia produced by the injection of organisms into the internal carotid artery, even though intraparenchymal microabscesses with yeasts and pseudohyphae were seen throughout the brain. Candida albicans was culturally identified in the brain and kidney. Injecting the organisms into the cisterna magna caused an infection characterized by lymphocytes and histiocytes and was confined to the leptomeninges. In this meningeal model, fungi were recovered only from the CNS. The overwhelming prevalence at autopsy of cerebral candidal microabscesses without diffuse leptomeningitis is apparently due to transient candidemia. Meningitis due to candidemia is rare and seems to require a microabscess that is accessible to the circulating CSF. This latter event is a late and overwhelming feature of cerebral candidiasis.
Insights
Transient candidemia in rats did not cause diffuse leptomeningitis, despite brain microabscesses. Meningitis occurred only when Candida albicans directly infected the meninges, highlighting rare routes of fungal brain infection.
Area of Science:
- Neuroscience
- Infectious Diseases
- Mycology
Background:
- * Candidemia, a bloodstream fungal infection, can potentially spread to the central nervous system (CNS).
- * The development of fungal meningitis from candidemia is considered rare.
- * Understanding the pathways of fungal CNS invasion is crucial for effective treatment.
Purpose of the Study:
- * To investigate the pathological outcomes of transient candidemia in the rat brain.
- * To differentiate between intraparenchymal fungal brain infection and fungal meningitis.
- * To explore the conditions under which candidemia may lead to leptomeningitis.
Main Methods:
- * Healthy adult male Wistar rats were subjected to transient candidemia via internal carotid artery injection of Candida albicans.
- * A separate group of rats received direct injection of Candida albicans into the cisterna magna to establish a meningeal infection model.
- * Brains and kidneys were examined for fungal presence, and histopathological analysis was performed on infected tissues.
Main Results:
- * Transient candidemia resulted in widespread intraparenchymal microabscesses in the brain, but not diffuse leptomeningitis.
- * Candida albicans was culturally confirmed in the brain and kidneys of rats with candidemia.
- * Direct injection into the cisterna magna led to leptomeningitis characterized by inflammatory cells, confined to the meninges, with fungi only recovered from the CNS.
Conclusions:
- * Intraparenchymal microabscesses from transient candidemia do not typically progress to diffuse leptomeningitis.
- * Fungal meningitis due to candidemia appears to necessitate a brain microabscess accessible to cerebrospinal fluid (CSF).
- * This accessibility is a late-stage complication of cerebral candidiasis, explaining the rarity of meningitis.