Methicillin-Resistant Staphylococcus aureus is best described as:

Methicillin-Resistant Staphylococcus aureus is best described as:

• A. A strain of Staphylococcus aureus that is resistant to many antibiotics
• B. A virus causing hemorrhagic fever
• C. A fungus causing skin infection
• D. A nutrient supplement

Answer: (A)

The basic idea is that MRSA is a bacterium with a specific resistance trait. Methicillin-Resistant Staphylococcus aureus is a strain of Staphylococcus aureus that has acquired resistance to methicillin and to many other antibiotics, making infections harder to treat. Staphylococcus aureus is a common bacterium that can live on the skin or in the nose, and when it gains the mecA gene, it produces a penicillin-binding protein (PBP2a) with low affinity for beta-lactam antibiotics. That means methicillin and related drugs can’t effectively kill it, so infections may require non-beta-lactam antibiotics and careful infection control. It’s not a virus, not a fungus, and not a nutrient supplement, which is why these other descriptions don’t fit.

The basic idea is that MRSA is a bacterium with a specific resistance trait. Methicillin-Resistant Staphylococcus aureus is a strain of Staphylococcus aureus that has acquired resistance to methicillin and to many other antibiotics, making infections harder to treat. Staphylococcus aureus is a common bacterium that can live on the skin or in the nose, and when it gains the mecA gene, it produces a penicillin-binding protein (PBP2a) with low affinity for beta-lactam antibiotics. That means methicillin and related drugs can’t effectively kill it, so infections may require non-beta-lactam antibiotics and careful infection control. It’s not a virus, not a fungus, and not a nutrient supplement, which is why these other descriptions don’t fit.