An intensive care unit reports rising gentamicin and tobramycin resistance among Gram-negative isolates due to plasmid-encoded aminoglycoside-modifying enzymes. Which aminoglycoside retains activity against the widest range of these enzymatic modifications?
- A Streptomycin
- B Netilmicin
- C Amikacin ✓
- D Neomycin
Correct answer: C. Amikacin
Explanation
Amikacin is a semisynthetic derivative of kanamycin in which the amino group is protected by a hydroxyaminobutyryl side chain. This side chain sterically hinders most aminoglycoside-modifying enzymes, so fewer than 10 percent of known enzymes can inactivate it, making it the agent of choice when resistance to gentamicin and tobramycin emerges. Streptomycin is the most readily inactivated by modifying enzymes.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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