Which agent is commonly used to cover MRSA when treating hospital-acquired pneumonia?

Which agent is commonly used to cover MRSA when treating hospital-acquired pneumonia?

• A. Ceftriaxone
• B. Amikacin
• C. Vancomycin
• D. Aztreonam

Answer: (C)

Covering MRSA in hospital-acquired pneumonia requires an agent that is active against MRSA. Vancomycin fits this role because it inhibits bacterial cell-wall synthesis by binding to the D-Ala-D-Ala terminus of peptidoglycan, and MRSA strains are susceptible to it despite resistance to many beta-lactams. The other options do not reliably cover MRSA: ceftriaxone is a beta-lactam with good activity against many Gram-positives but not dependable for MRSA; amikacin targets primarily Gram-negative bacteria and has limited utility in pneumonia due to penetration issues and lack of MRSA activity; aztreonam is active only against Gram-negative organisms. Thus, vancomycin is the best choice when MRSA coverage is needed in hospital-acquired pneumonia.

Covering MRSA in hospital-acquired pneumonia requires an agent that is active against MRSA. Vancomycin fits this role because it inhibits bacterial cell-wall synthesis by binding to the D-Ala-D-Ala terminus of peptidoglycan, and MRSA strains are susceptible to it despite resistance to many beta-lactams. The other options do not reliably cover MRSA: ceftriaxone is a beta-lactam with good activity against many Gram-positives but not dependable for MRSA; amikacin targets primarily Gram-negative bacteria and has limited utility in pneumonia due to penetration issues and lack of MRSA activity; aztreonam is active only against Gram-negative organisms. Thus, vancomycin is the best choice when MRSA coverage is needed in hospital-acquired pneumonia.