**Question:** V. cholera is able to stay in GIT because of -

A. Adhesion to intestinal epithelium
B. Production of enterotoxin
C. Formation of biofilm
D. Bacteriophage resistance

**Core Concept:** Vibrio cholera is a Gram-negative bacterium that causes cholera, a severe watery diarrhea. Its ability to survive and colonize the gastrointestinal tract (GIT) is crucial for its pathogenesis.

**Why the Correct Answer is Right:** V. cholera can adhere to the intestinal epithelium through its specific adhesin, Vibrio cholerae adhesion protein (VCA). This adhesion allows the bacterium to attach to the intestinal cells, preventing its elimination and enabling colonization of the GIT.

**Why Each Wrong Option is Incorrect:**

A. Adhesion to intestinal epithelium: As mentioned above, this is the correct mechanism, so this option is incorrect.
B. Production of enterotoxin (Vibrio cholera toxin, VCT): While VCT is a key factor in causing diarrhea, it does not explain V. cholera's ability to stay in the GIT.
C. Formation of biofilm: Although biofilm formation can protect bacteria from host defenses and antibiotics, it is not specifically associated with V. cholera's ability to stay in the GIT.
D. Bacteriophage resistance: V. cholera's ability to survive phages is essential for its survival in the environment, but not directly related to its colonization of the GIT.

**Clinical Pearl:** Understanding V. cholera's strategies for GIT colonization is essential for understanding cholera pathogenesis and developing appropriate treatments and prevention measures.

**Correct Answer:** A. Adhesion to intestinal epithelium

---

**Core Concept:** Vibrio cholera is known for its ability to cause severe diarrhea through the production of the cholera toxin. However, the bacterium's ability to stay in the gastrointestinal tract (GIT) is crucial for its pathogenesis and persistence in the host.

**Why the Correct Answer is Right:** V. cholera possesses a specific adhesin, Vibrio cholera adhesion protein (VCA), which allows it to adhere to the intestinal epithelium. This adhesion prevents the bacterium from being eliminated from the host and enables colonization of the GIT.

**Why Each Wrong Option is Incorrect:**

A. Adhesion to intestinal epithelium: This is the correct mechanism, so this option is not incorrect.
B. Production of enterotoxin (Vibrio cholera toxin): While V. cholera toxin is responsible for causing diarrhea, it is not directly related to the bacterium's ability to stay in the GIT.
C. Formation of biofilm: Although biofilms protect bacteria from host defenses and antibiotics, they are not specifically associated with V. cholera's ability to colonize the GIT.
D. Resistance to bacteriophages: V. cholera's resistance to bacteriophages is vital for its survival in the environment, but