An intensivist wants a carbapenem for a patient with ESBL-producing Klebsiella pneumoniae ventilator-associated pneumonia who also has concurrent Pseudomonas aeruginosa bacteremia. Which carbapenem would be an inappropriate choice for this combined indication?
- A Meropenem
- B Imipenem-cilastatin
- C Ertapenem ✓
- D Doripenem
Correct answer: C. Ertapenem
Explanation
Ertapenem reliably covers ESBL-producing Enterobacterales but lacks clinically meaningful activity against Pseudomonas aeruginosa and Acinetobacter species because its structure limits outer membrane penetration in these organisms. Meropenem, imipenem-cilastatin and doripenem all provide antipseudomonal coverage along with ESBL cover. Choosing ertapenem here would leave the Pseudomonas bacteremia untreated. Ertapenem's advantage is once-daily dosing and lower seizure risk than imipenem.
Reference: Katzung Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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