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Acute uncomplicated lower urinary tract infection in a non-pregnant woman — MSRA MCQ

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HardUrinary Tract InfectionsAcute uncomplicated lower urinary tract infection in a non-pregnant womanMSRA

A 34-year-old non-pregnant woman presents with 36 hours of severe dysuria, frequency and urgency, which are preventing her from working. She has no fever, rigors, loin pain, vomiting, vaginal discharge or pelvic pain. She is haemodynamically stable and has no urinary tract abnormality or catheter. Following discussion, she requests immediate antibiotic treatment rather than a back-up prescription. She has stable chronic kidney disease with an eGFR of 38 mL/minute/1.73 m². Six months ago, a urine culture grew Escherichia coli resistant to trimethoprim but susceptible to nitrofurantoin; it was not multidrug-resistant. At age 19, amoxicillin caused immediate urticaria, wheeze and hypotension requiring emergency treatment. She has taken no antibiotics in the past 3 months. What is the most appropriate immediate oral antibiotic regimen?

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Correct answer: D — Fosfomycin 3 g as a single oral dose

This is an uncomplicated lower UTI: she has localised urinary symptoms without fever, loin pain, vomiting or systemic illness to suggest pyelonephritis. Immediate treatment is reasonable because symptoms are severe and she prefers this after discussion. Nitrofurantoin is normally first-line, but at an eGFR of 30–44 mL/minute it is reserved for uncomplicated lower UTI caused by suspected or proven multidrug-resistant organisms when benefit outweighs risk. Her previous isolate was resistant to trimethoprim alone, not multidrug-resistant. Trimethoprim is additionally inappropriate because her previous culture demonstrated resistance. Pivmecillinam is a penicillin and is contraindicated with her previous immediate severe penicillin hypersensitivity reaction. Fosfomycin 3 g single dose is therefore the NICE-listed second-choice option when first-line treatment is unsuitable. Cefalexin is not a routine NICE second-choice regimen for non-pregnant women with uncomplicated lower UTI and would require a culture-directed or local microbiology rationale.

Reference: NICE NG109: Urinary tract infection (lower): antimicrobial prescribing — Recommendations (2018; amended July 2019) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations NICE NG109: Urinary tract infection (lower): antimicrobial prescribing — Recommendations (2018; amended July 2019) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations Pivmecillinam 200 mg film-coated tablets — Summary of Product Characteristics (2026) — https://www.medicines.org.uk/emc/product/4982/smpc