The bacterium causing pseudomembranous colitis is
a. Clostridium difficile
b. Streptococcus pyogenes
c. Mycobacterium avium-intracellulare
d. Corynebacterium diphtheriae

Verified step by step guidance

1. Step 1: Understand the disease pseudomembranous colitis, which is an inflammation of the colon characterized by the formation of pseudomembranes on the colon lining, often associated with antibiotic use.
2. Step 2: Recall that pseudomembranous colitis is primarily caused by a bacterial infection that produces toxins leading to colonic inflammation.
3. Step 3: Review the options given: a) Clostridium difficile, b) Streptococcus pyogenes, c) Mycobacterium avium-intracellulare, d) Corynebacterium diphtheriae.
4. Step 4: Identify that Clostridium difficile is a spore-forming, anaerobic bacterium known to cause antibiotic-associated diarrhea and pseudomembranous colitis by producing enterotoxins.
5. Step 5: Conclude that among the options, Clostridium difficile is the bacterium responsible for pseudomembranous colitis.

Key Concepts

Pseudomembranous Colitis

Pseudomembranous colitis is an inflammation of the colon characterized by the formation of pseudomembranes on the intestinal lining. It typically occurs after antibiotic use disrupts normal gut flora, allowing pathogenic bacteria to overgrow and cause severe diarrhea and colonic damage.

Clostridium difficile

Clostridium difficile is a Gram-positive, spore-forming anaerobic bacterium known to cause antibiotic-associated diarrhea and pseudomembranous colitis. It produces toxins that damage the intestinal mucosa, leading to inflammation and the characteristic pseudomembranes.

Differentiation of Bacterial Pathogens

Understanding the specific diseases caused by different bacteria is essential in microbiology. For example, Streptococcus pyogenes causes strep throat, Mycobacterium avium-intracellulare is linked to opportunistic infections in immunocompromised patients, and Corynebacterium diphtheriae causes diphtheria, not colitis.