**Question:** Donovanosis is caused by ?

**Core Concept:** Donovanosis is a chronic granulomatous inflammatory disease caused by the bacterium Klebsiella pneumoniae.

**Why the Correct Answer is Right:** Donovanosis is primarily caused by the bacterium Klebsiella pneumoniae, a Gram-negative facultative anaerobe. When the bacterium enters the human body, it invades the mucous membranes, particularly in the oral and genital regions, leading to the formation of ulcers and granulomas. This process results in the characteristic clinical features of the disease.

**Why Each Wrong Option is Incorrect:**

A. **Klebsiella oxytoca (Option A)** is another Klebsiella species, but it is not the causative agent of donovanosis.

B. **Klebsiella oxytoca (Option B)** is similar to Option A, but it is not responsible for donovanosis.

C. **Klebsiella rhinoscleromatis (Option C)** is another Klebsiella species, but it is not the causative agent of donovanosis.

D. **Klebsiella rhinoscleromatis (Option D)** is similar to Option C, but it is not responsible for donovanosis.

**Clinical Pearl:** Donovanosis is a rare disease, but it is prevalent in some parts of Africa, Asia, and South America. Early diagnosis and treatment are crucial to prevent severe complications, including bone and joint involvement.

**Correct Answer:** D. Klebsiella rhinoscleromatis (Option D) is not the correct answer since it is not the causative agent of donovanosis. The correct answer is Klebsiella pneumoniae (Option C).