Which mechanism of antibiotic resistance is shared by both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Staphylococcus aureus (VRSA)?

• A. Efflux pump-mediated antibiotic removal
• B. Decreased permeability of the cell wall to antibiotics
• C. Production of beta-lactamase enzymes
• D. Acquisition of altered target proteins (e.g., modified penicillin-binding proteins)

Answer: (D)

Verified step by step guidance

1. Understand that antibiotic resistance mechanisms can vary, but some are common across different resistant strains of bacteria.
2. Identify the specific resistance mechanisms for MRSA and VRSA: MRSA is resistant due to altered penicillin-binding proteins (PBPs), which reduce the effectiveness of beta-lactam antibiotics like methicillin.
3. Recognize that VRSA resistance involves changes in the target site of vancomycin, specifically alterations in the cell wall precursors that vancomycin binds to, effectively modifying the target.
4. Note that both MRSA and VRSA share a common theme: they acquire altered target proteins or structures that reduce antibiotic binding, rather than relying on mechanisms like efflux pumps or enzyme production.
5. Conclude that the shared mechanism is the acquisition of altered target proteins, which prevents antibiotics from effectively binding and inhibiting their bacterial targets.