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Complicated urinary tract infection — ABIM Board MCQ

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HardInfectious DiseaseComplicated urinary tract infectionABIM Board

A 76-year-old with diabetes and CKD presents with fever, flank pain, confusion, pyuria and bacteriuria. She took ciprofloxacin two months ago, local fluoroquinolone resistance is high, and prior cultures show no ESBL organism. Blood pressure is stable. Which empiric therapy is appropriate pending cultures?

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Correct answer: D — Begin ceftriaxone after obtaining blood and urine cultures

The best answer is “Begin ceftriaxone after obtaining blood and urine cultures”. This systemic complicated UTI requires prompt empiric therapy informed by severity, recent antibiotics, prior cultures, kidney function and the local antibiogram. Ceftriaxone is a reasonable initial third-generation cephalosporin here. Nitrofurantoin does not treat renal parenchymal infection, and delaying active therapy or ignoring fluoroquinolone resistance is unsafe.

Reference: IDSA 2025 Complicated Urinary Tract Infection Guideline: https://www.idsociety.org/practice-guideline/complicated-urinary-tract-infections/