Most common organism responsible for pseudomembranous colitis is
**Core Concept**
Pseudomembranous colitis, also known as Clostridioides difficile (C. difficile) infection, is a type of colitis caused by a bacterial infection. It typically occurs after antibiotic use, which disrupts the normal gut flora, allowing the pathogenic bacterium to overgrow and cause disease.
**Why the Correct Answer is Right**
The correct answer is Clostridioides difficile, a Gram-positive, spore-forming bacterium. C. difficile produces toxins A and B, which damage the intestinal lining and cause the characteristic pseudomembrane formation. The toxins also trigger an inflammatory response, leading to symptoms such as diarrhea, abdominal pain, and fever. The bacterium is highly contagious and can spread through contaminated food, water, or surfaces, as well as through direct contact with an infected person.
**Why Each Wrong Option is Incorrect**
**Option A:** Escherichia coli (E. coli) is a common cause of urinary tract infections and some cases of diarrhea, but it is not typically associated with pseudomembranous colitis.
**Option B:** Salmonella species can cause gastroenteritis, but they are not the primary cause of pseudomembranous colitis.
**Option C:** Staphylococcus aureus can cause food poisoning and skin infections, but it is not commonly associated with pseudomembranous colitis.
**Clinical Pearl / High-Yield Fact**
When treating C. difficile infection, it's essential to stop the causative antibiotic and initiate metronidazole or vancomycin therapy. Additionally, infection control measures, such as hand hygiene and environmental cleaning, are crucial to prevent transmission.
**Correct Answer:** C. Clostridioides difficile.