skip to main content

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

Instant feedback + full explanation. One question, done properly.

ModerateUrinary Tract InfectionsPersistent uncomplicated lower urinary tract infection in a non-pregnant womanMSRA

A 31-year-old non-pregnant woman is reviewed 48 hours after starting nitrofurantoin 100 mg modified-release twice daily for suspected lower UTI. At presentation she had dysuria, urinary frequency and urgency, with no vaginal discharge, fever, rigors, loin pain, vomiting or visible haematuria. A midstream urine specimen was sent before treatment. Her symptoms have not improved. She remains haemodynamically stable, is drinking normally and has no costovertebral-angle tenderness. Her eGFR is 86 mL/minute/1.73 m² and she has no drug allergies. Urine culture has grown >10⁵ CFU/mL Escherichia coli, resistant to nitrofurantoin, trimethoprim and fosfomycin, but susceptible to pivmecillinam. What is the most appropriate management now?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Stop nitrofurantoin and prescribe pivmecillinam 400 mg initially, then 200 mg three times daily for a total of 3 days

Explanation lettering: D = shown as A · C = shown as B · E = shown as C · A = shown as D · B = shown as E

This remains a lower UTI: she has persistent local urinary symptoms but no fever, loin pain, vomiting, systemic instability or examination findings suggesting pyelonephritis. NICE advises reassessment when symptoms have not started to improve after 48 hours of antibiotics. Where culture demonstrates resistance and symptoms are not improving, treatment should be changed according to susceptibility results, using a narrow-spectrum agent where possible. Pivmecillinam is an appropriate second-choice agent for non-pregnant women when first-choice treatment has failed after at least 48 hours or is unsuitable. The recommended regimen is 400 mg initially, followed by 200 mg three times daily, for a total course of 3 days. A is inappropriate because both clinical response and susceptibility testing indicate nitrofurantoin treatment failure. B omits the recommended 400 mg initial dose. C uses an unnecessarily prolonged course; 7-day courses are used in different populations, notably pregnancy or men, rather than uncomplicated lower UTI in a non-pregnant woman. D would otherwise be a guideline-listed second-choice option, but this isolate is resistant to fosfomycin.

Reference: Urinary tract infection (lower): antimicrobial prescribing (NG109) — Recommendations (Published 31 October 2018; last updated May 2025) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations Urinary tract infection (lower): antimicrobial prescribing (NG109) — Table 1 (Published 31 October 2018; last updated May 2025) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations