Most common fungal infection in neutropenic patient is: September 2005
**Core Concept**
Fungal infections, particularly in neutropenic patients, are a significant concern in oncology and hematology. Neutropenia increases the risk of fungal infections due to compromised immune function, making these patients susceptible to opportunistic pathogens.
**Why the Correct Answer is Right**
Aspergillus species are the most common cause of fungal infections in neutropenic patients. This is because Aspergillus spp. are ubiquitous in the environment and can easily colonize the respiratory tract, leading to invasive aspergillosis. The pathogenesis involves the inhalation of Aspergillus spores, which germinate into hyphae that invade the lung tissue and disseminate to other organs. The lack of neutrophils in neutropenic patients hampers the body's ability to contain this fungal invasion.
**Why Each Wrong Option is Incorrect**
* **Option A:** While Candida species are common fungal pathogens, they are more commonly associated with mucosal and cutaneous infections rather than invasive disease in neutropenic patients.
* **Option B:** Histoplasma capsulatum is a dimorphic fungus that typically causes pulmonary disease in immunocompetent individuals, not neutropenic patients.
* **Option C:** Pneumocystis jirovecii is a fungal pathogen that primarily affects immunocompromised patients with CD4+ T-cell counts below 200 cells/μL, not neutropenic patients.
**Clinical Pearl / High-Yield Fact**
Aspergillus infections are more common in patients who have undergone bone marrow transplantation, have received broad-spectrum antibiotics, or have a history of corticosteroid use.
**Correct Answer:** C. Aspergillus.