Which is not true of cryptococcus neoformans –
**Core Concept**
Cryptococcus neoformans is a type of encapsulated yeast that causes cryptococcosis, primarily affecting immunocompromised individuals. It is a major cause of fungal meningitis and pneumonia in HIV/AIDS patients.
**Why the Correct Answer is Right**
Cryptococcus neoformans is known for its polysaccharide capsule, which is composed mainly of glucuronoxylomannan (GXM). This capsule is crucial for its virulence and ability to evade the host's immune system. The organism is typically acquired through inhalation of spores from contaminated soil or bird droppings. Upon infection, it primarily affects the lungs and the central nervous system (CNS), leading to cryptococcal meningitis.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because Cryptococcus neoformans is indeed a type of encapsulated yeast.
**Option B:** Incorrect because the organism is typically acquired through inhalation of spores, not ingestion.
**Option C:** Incorrect because the polysaccharide capsule of Cryptococcus neoformans is indeed composed mainly of glucuronoxylomannan (GXM).
**Clinical Pearl / High-Yield Fact**
Early diagnosis and treatment of cryptococcal meningitis are crucial, as it can lead to significant morbidity and mortality. Amphotericin B and flucytosine are the recommended antifungal agents for treatment, often followed by fluconazole for maintenance therapy.
**Correct Answer: D.**