INI-CET 2026 — Microbiology

Q: A diabetic patient presents with facial pain, black nasal eschar and eye pain following corticosteroid therapy. What is the etiological agent?

Rhizopus. ***Rhizopus*** - This species belongs to the order Mucorales, the primary causative agents of **rhinocerebral mucormycosis** in immunocompromised hosts, especially in patients with **diabetic ketoacidosis**. - The clinical presentation of **facial pain**, **black nasal eschar** (due to tissue necrosis/infarction), and **eye pain** (orbital involvement) is the classic hallmark of this invasive fungal infection. *Candida tropicalis* - Typically causes **candidemia** or disseminated candidiasis in immunocompromised patients, but it does not classically present with necrotic nasal eschars. - It is a yeast, whereas the cause of this patient's condition is an **angioinvasive mold**. *Aspergillus fumigatus* - While it can cause sinusitis in immunocompromised patients, it typically presents with **allergic fungal sinusitis** or invasive disease without the classic black eschar. - It is characterized by **septate hyphae** with acute angle branching, differing from the broad, non-septate hyphae of Mucorales. *Cryptococcus neoformans* - Usually presents as **meningoencephalitis** or pulmonary infection, particularly in patients with advanced HIV/AIDS. - It is an encapsulated yeast and does not cause the rapid, destructive tissue necrosis associated with **black eschar** formation in the sinuses.

11 Questions — Page 2 of 2

Q11

A diabetic patient presents with facial pain, black nasal eschar and eye pain following corticosteroid therapy. What is the etiological agent?