False about Bacillus anthracis is
**Core Concept**
Bacillus anthracis is a gram-positive, rod-shaped bacterium that is the causative agent of anthrax, a zoonotic disease affecting both animals and humans. It is a spore-forming bacterium that can survive in the environment for extended periods.
**Why the Correct Answer is Right**
Bacillus anthracis produces two main toxins: the lethal factor (LF) and the edema factor (EF), which are responsible for the systemic and local effects of anthrax. The LF inhibits the host's protein kinase A, leading to cell death, while the EF causes edema by activating adenylate cyclase, resulting in increased cyclic AMP levels. The capsule, composed of poly-D-glutamic acid, is essential for the bacterium's virulence and protects it from phagocytosis.
**Why Each Wrong Option is Incorrect**
**Option A:** Bacillus anthracis is a gram-negative bacterium. *This is incorrect because Bacillus anthracis is actually a gram-positive bacterium.*
**Option B:** The capsule of Bacillus anthracis is composed of lipopolysaccharides. *This is incorrect because the capsule of Bacillus anthracis is actually composed of poly-D-glutamic acid.*
**Option C:** Bacillus anthracis is a spore-forming bacterium that is highly susceptible to antibiotics. *This is incorrect because Bacillus anthracis is actually resistant to many antibiotics, and its spores can survive in the environment for extended periods.*
**Clinical Pearl / High-Yield Fact**
The capsule of Bacillus anthracis is a key virulence factor, and its presence can be detected using the capsule staining test.
**Correct Answer: B. The capsule of Bacillus anthracis is composed of lipopolysaccharides.**