Moraxella catarrhalis is resistant to which antibiotic?
**Core Concept**
Moraxella catarrhalis is a gram-negative bacterium that commonly causes respiratory tract infections. Its antibiotic resistance pattern is a crucial aspect of its management. **Beta-lactamase production** is a key mechanism of resistance in this bacterium.
**Why the Correct Answer is Right**
Moraxella catarrhalis often produces **beta-lactamases**, enzymes that inactivate beta-lactam antibiotics like ampicillin. This intrinsic resistance makes ampicillin less effective against M. catarrhalis. The production of **broader-spectrum beta-lactamases** can also confer resistance to other antibiotics.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we cannot assess its accuracy.
**Option B:** This option is not provided, so we cannot assess its accuracy.
**Option C:** This option is not provided, so we cannot assess its accuracy.
**Option D:** This option is not provided, so we cannot assess its accuracy.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that Moraxella catarrhalis is often resistant to ampicillin due to its **beta-lactamase production**. This is crucial for choosing the appropriate antibiotic therapy.
**Correct Answer:** D. Ampicillin