A 45-year-old female patient with a urinary tract infection due to an extended-spectrum beta-lactamase (ESBL)-producing E. coli is hospitalized. The antibiotic class of CHOICE for ESBL infections is:
- A Cefepime (4th generation cephalosporin) with a beta-lactamase inhibitor
- B Carbapenems (imipenem, meropenem, ertapenem) ✓
- C Aztreonam monotherapy
- D Piperacillin-tazobactam if minimum inhibitory concentrations are susceptible
Correct answer: B. Carbapenems (imipenem, meropenem, ertapenem)
Explanation
Carbapenems (imipenem-cilastatin, meropenem, ertapenem) are the drugs of choice for serious infections caused by ESBL-producing organisms. ESBL enzymes hydrolyze all penicillins and cephalosporins (including cefepime), and resistance is often transferable to other classes. Carbapenems are resistant to ESBL hydrolysis due to their unique bicyclic structure. Piperacillin-tazobactam may appear susceptible in vitro but demonstrates an 'inoculum effect' and clinical failures, making it unreliable for serious ESBL infections.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.