A vitreous aspirate from a case of metastatic endophthalmitis on culture yields Gram-positive round to oval cells, 12-14 m in size. The aspirate on Gram staining shows the presence of pseudohyphae. Which of the following is the most likely aetiological agent

**Core Concept**
The question requires the identification of a microorganism based on its morphological characteristics and the presence of pseudohyphae. **Fungal endophthalmitis** is a severe infection of the inner eye, and the description points towards a **fungal** aetiology, specifically one that is **Gram-positive** and exhibits **pseudohyphae**.

**Why the Correct Answer is Right**
Given the description of Gram-positive round to oval cells, 12-14 μm in size, and the presence of pseudohyphae, the most likely organism is **Candida** species. **Candida** is known for its ability to form pseudohyphae, which are characteristic of its pathogenic form. This fungus is a common cause of endophthalmitis, especially in immunocompromised patients or those with a history of intraocular surgery or intravenous drug use.

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because the description does not match the typical presentation of the organism associated with this option.
**Option B:** Similarly, this choice does not align with the characteristics provided in the question.
**Option C:** This option is also incorrect as it does not fit the morphological description given.
**Option D:** This is not the correct answer because, although it could be a fungal infection, the specific details in the question point more accurately to another organism.

**Clinical Pearl / High-Yield Fact**
In cases of suspected fungal endophthalmitis, particularly with **Candida**, prompt diagnosis and treatment are crucial to prevent severe visual loss. The presence of pseudohyphae is a key diagnostic feature, indicating the pathogenic form of the fungus.

**Correct Answer:** D. Candida albicans

✓ Correct Answer: C. Candida