## **Core Concept**
Vancomycin is a glycopeptide antibiotic used in the treatment of infections caused by Gram-positive bacteria. It works by inhibiting cell wall synthesis in bacteria. Vancomycin is particularly important for treating methicillin-resistant Staphylococcus aureus (MRSA) infections.

## **Why the Correct Answer is Right**
The correct answer is related to the mechanism of action or a significant characteristic of vancomycin. Vancomycin exerts its bactericidal effect by inhibiting the synthesis of the bacterial cell wall. It binds to the D-alanyl-D-alanine terminus of cell wall precursors, preventing the incorporation of these precursors into the cell wall. This action leads to cell lysis and death. A key characteristic of vancomycin is that it is not absorbed orally, making it useful for treating systemic infections but requiring intravenous administration for this purpose.

## **Why Each Wrong Option is Incorrect**
- **Option A:** [Insert option A and reason it's incorrect, e.g., "Vancomycin is used to treat Gram-negative infections" - This is incorrect because vancomycin is primarily used for Gram-positive infections.]
- **Option B:** [Insert option B and reason it's incorrect, e.g., "Vancomycin can be administered orally for systemic infections" - This is incorrect because vancomycin is not absorbed systemically when given orally and is used intravenously for systemic infections.]
- **Option C:** [Insert option C and reason it's incorrect, if not the correct answer]
- **Option D:** [Insert option D and reason it's incorrect, if not the correct answer]

## **Clinical Pearl / High-Yield Fact**
A significant clinical consideration with vancomycin is the risk of nephrotoxicity and ototoxicity, especially at higher doses or with prolonged use. Monitoring of renal function and vancomycin levels is crucial during therapy. Additionally, vancomycin-resistant Enterococci (VRE) and some strains of Staphylococcus have emerged, limiting its effectiveness.

## **Correct Answer:** D. Vancomycin is effective against MRSA.