Which antibiotic is an aminoglycoside used as anti-pseudomonal coverage?

• A. Piperacillin-tazobactam
• B. Cefepime
• C. Amikacin
• D. Vancomycin

Answer: (C)

Aminoglycosides are bactericidal antibiotics that inhibit protein synthesis by binding to the 30S ribosomal subunit and are particularly effective against gram-negative bacteria, including Pseudomonas aeruginosa. Amikacin stands out among aminoglycosides for anti-pseudomonal coverage because it generally retains activity against Pseudomonas strains that are resistant to gentamicin or tobramycin, making it a reliable option in serious Pseudomonas infections. In practice, it’s often used in combination with a beta-lactam to achieve synergistic killing, since the beta-lactam disrupts the cell wall and facilitates aminoglycoside uptake. The other drugs listed are not aminoglycosides: one is a beta-lactam/beta-lactamase inhibitor with anti-pseudomonal activity, another is a fourth-generation cephalosporin with anti-pseudomonal activity, and the last is a glycopeptide mainly targeting gram-positive organisms and not Pseudomonas. Therefore, the aminoglycoside used for anti-pseudomonal coverage is amikacin.