Most common organism responsible for pseudo membranous colitis is –
**Core Concept**
Pseudo membranous colitis, also known as antibiotic-associated colitis, is a condition characterized by inflammation of the colon and the formation of a pseudo-membrane, leading to symptoms such as diarrhea, abdominal pain, and bloody stools. This condition is often caused by an imbalance of the normal gut microbiota.
**Why the Correct Answer is Right**
The most common organism responsible for pseudo membranous colitis is Clostridioides difficile (C. difficile). C. difficile is a gram-positive, spore-forming bacterium that overgrows in the gut when the normal bacteria are suppressed by antibiotics. The toxins produced by C. difficile, specifically toxin A and toxin B, cause damage to the intestinal lining, leading to the formation of a pseudo-membrane and the characteristic symptoms of pseudo membranous colitis.
**Why Each Wrong Option is Incorrect**
**Option A:** Escherichia coli (E. coli) is a common gut bacterium, but it is not typically associated with pseudo membranous colitis.
**Option B:** Klebsiella pneumoniae is a gram-negative bacterium that can cause various infections, but it is not the primary cause of pseudo membranous colitis.
**Option C:** Staphylococcus aureus is a gram-positive bacterium that can cause skin and soft tissue infections, but it is not commonly associated with pseudo membranous colitis.
**Clinical Pearl / High-Yield Fact**
C. difficile infection (CDI) is a significant cause of healthcare-associated diarrhea and colitis, and its diagnosis is often confirmed by toxin testing or PCR.
**Correct Answer:** C. Clostridioides difficile.