A 34 year old man diagnosed of having H. pylori infection after biopsy. Where can H. pylori be found in the stomach?
**Core Concept**
The underlying principle being tested is the understanding of the **pathophysiology** of _Helicobacter pylori_ (_H. pylori_) infection in the stomach. _H. pylori_ is a **gram-negative bacterium** that infects the **gastric mucosa**. It is a major cause of **peptic ulcers** and **gastric cancer**.
**Why the Correct Answer is Right**
_H. pylori_ can be found in the **gastric mucosa**, specifically in the **antrum** of the stomach, where it adheres to the **epithelial cells**. The bacterium produces **urease**, which breaks down **urea** into **ammonia** and **carbon dioxide**, creating a more **alkaline environment** that allows it to survive in the acidic stomach.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because _H. pylori_ is not typically found in the **esophagus**.
**Option B:** Incorrect because _H. pylori_ is not typically found in the **duodenum**, although it can cause **duodenal ulcers**.
**Option C:** Incorrect because _H. pylori_ is not typically found in the **jejunum**.
**Why Each Wrong Option is Incorrect (continued)**
**Option D:** Incorrect, as the correct location is more specific than this option.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that _H. pylori_ infection is associated with an increased risk of **gastric cancer** and **peptic ulcers**.
**Correct Answer:** D. Antrum of the stomach