Which bacterium causes peptic ulcers? Who discovered the above pahotgen for the first time?

Explanation

### Step-by-Step Solution:

1. **Identify the Bacterium**: The bacterium that causes peptic ulcers is **Helicobacter pylori**. This bacterium is known to create open sores in the inner lining of the stomach and the upper portion of the small intestine.

2. **Discovery of the Pathogen**: The bacterium Helicobacter pylori was first discovered by **Barry Marshall** and **Robin Warren**. They conducted research that led to the identification of this pathogen as a significant cause of peptic ulcers.

3. **Understanding Peptic Ulcers**: Peptic ulcers are essentially open sores that can cause various symptoms, with the most common being stomach pain.

### Final Answer:
- The bacterium that causes peptic ulcers is **Helicobacter pylori**.
- It was discovered by **Barry Marshall** and **Robin Warren**.

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