Cryptococcus neoformans is a
fungus
gram-positive bacterium
gram-negative bacterium
prion
The correct answer and explanation is :
The correct answer is fungus.
Cryptococcus neoformans is a pathogenic yeast-like fungus that is commonly found in the environment, particularly in soil and decaying organic material such as pigeon droppings. It is known to cause infections primarily in immunocompromised individuals, such as those with HIV/AIDS, cancer, or those undergoing immunosuppressive treatments.
Explanation:
- Classification:
Cryptococcus neoformans is classified as a fungus belonging to the Basidiomycota division. It exists primarily in its yeast form, which distinguishes it from other fungi that might have filamentous structures. The yeast cells are typically spherical or oval and can form a thick, gelatinous capsule, which is a significant virulence factor. - Infection and Virulence:
The primary route of infection with Cryptococcus neoformans is through inhalation of airborne spores (conidia), which can then infect the lungs. The fungus is capable of crossing the blood-brain barrier, leading to central nervous system infections, most notably cryptococcal meningitis. This infection is particularly dangerous for individuals with weakened immune systems, as it can spread to the brain and cause severe neurological symptoms. - Capsule and Immune Evasion:
The thick polysaccharide capsule that surrounds Cryptococcus neoformans plays a crucial role in its pathogenicity. This capsule helps the fungus evade the host’s immune system by inhibiting phagocytosis by macrophages, thus enabling it to survive and proliferate within the host’s body. - Treatment:
Treatment of Cryptococcus neoformans infections typically involves antifungal medications such as amphotericin B and fluconazole. The treatment regime can vary depending on the severity of the infection and the patient’s immune status.
In summary, Cryptococcus neoformans is a fungus, not a bacterium or prion. It is an opportunistic pathogen that is capable of causing serious infections in individuals with weakened immune systems.