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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 46-year-old non-pregnant woman presents with 2 days of marked dysuria, urinary frequency and suprapubic discomfort that are disrupting sleep and work. She has no vaginal discharge, fever, rigors, loin pain, vomiting or visible haematuria. She is haemodynamically stable and can take oral medication. She has stable stage 3b chronic kidney disease (eGFR 40 mL/minute/1.73 m²) and confirmed G6PD deficiency. She developed anaphylaxis immediately after amoxicillin 8 years ago. A urine culture during a lower UTI 4 months ago grew Escherichia coli resistant to trimethoprim. She has not taken antibiotics since. A midstream urine sample can be obtained before treatment. What is the most appropriate immediate antimicrobial management?

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Correct answer: C — Obtain a midstream urine sample, then prescribe fosfomycin trometamol 3 g orally as a single dose.

This is symptomatic lower UTI without features of pyelonephritis or sepsis, so oral lower-UTI treatment is appropriate. Her symptoms are marked and she has chronic kidney disease, making an immediate rather than back-up prescription appropriate. Fosfomycin trometamol 3 g as a single dose is the appropriate NICE second-choice agent when first-choice options are unsuitable. Nitrofurantoin is unsuitable: the SmPC contraindicates it in G6PD deficiency and in renal dysfunction with eGFR below 45 mL/minute, apart from a restricted short-course exception for selected resistant uncomplicated infections. Trimethoprim is a poor empirical choice because the most recent isolate was resistant; NICE advises using previous culture results when selecting treatment. Pivmecillinam is contraindicated in people with hypersensitivity to penicillins and/or cephalosporins, so her immediate amoxicillin anaphylaxis excludes it. A back-up antibiotic strategy can be considered in non-pregnant women when immediate treatment is not necessary. Here, substantial symptom burden and increased risk of treatment failure mean treatment should not be deferred. The urine sample permits culture-directed review if symptoms persist or resistance is identified.

Reference: NICE NG109: Urinary tract infection (lower): antimicrobial prescribing — Recommendations (Published 31 October 2018; NICE guidance current page checked 16 August 2026) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations Nitrofurantoin CNX Therapeutics 100 mg Prolonged-Release Capsules — Summary of Product Characteristics (Updated 2025) — https://www.medicines.org.uk/emc/product/100300/smpc Pivmecillinam 200 mg film-coated tablets — Summary of Product Characteristics (Updated 2026) — https://www.medicines.org.uk/emc/product/4982/smpc