Which of the following organisms is intrinsically resistant to ALL aminoglycosides?
- A Pseudomonas aeruginosa
- B Bacteroides fragilis ✓
- C Klebsiella pneumoniae
- D Serratia marcescens
Correct answer: B. Bacteroides fragilis
Explanation
Aminoglycoside entry across the bacterial inner membrane is an oxygen-dependent, energy-requiring active transport process. Strictly anaerobic bacteria such as Bacteroides fragilis lack oxidative metabolism, so transport does not occur and the drug cannot reach its ribosomal target. Pseudomonas, Klebsiella and Serratia are aerobic Gram-negative bacilli and are classical aminoglycoside targets, though individual strains may acquire enzymatic resistance.
Reference: Katzung Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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