**Core Concept**
Meliodosis is a severe bacterial infection caused by a gram-negative rod, Burkholderia pseudomallei. This bacterium is typically found in soil and water in tropical and subtropical regions, particularly in Southeast Asia.

**Why the Correct Answer is Right**
Burkholderia pseudomallei is the primary causative agent of meliodosis, which can manifest as a skin infection, pneumonia, or septicemia. The bacterium enters the body through cuts or wounds in the skin or through inhalation of contaminated water droplets. Once inside, it can cause significant tissue damage and systemic inflammation due to its production of exotoxins and lipopolysaccharides.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the causative organism of meliodosis is not Burkholderia cepacia, which is a different species that can cause respiratory infections in cystic fibrosis patients.

**Option B:** This option is incorrect because Pseudomonas aeruginosa is a different bacterium that can cause a range of infections, including pneumonia and urinary tract infections, but it is not associated with meliodosis.

**Option C:** This option is incorrect because Klebsiella pneumoniae is a different bacterium that can cause pneumonia and urinary tract infections, but it is not the causative agent of meliodosis.

**Clinical Pearl / High-Yield Fact**
Meliodosis can mimic other infections such as leptospirosis, plague, and tuberculosis, making it essential to consider this diagnosis in patients with severe infections who have traveled to or reside in endemic areas.

**Correct Answer:** C. Burkholderia pseudomallei