Urinary tract infection in adults

Also known as UTI · Acute cystitis · Recurrent urinary tract infection · Pyelonephritis

GP-fellowship guide to urinary tract infection in adults: probability-based diagnosis in women and the limits of dipsticks, the uncomplicated-versus-complicated divide, the asymptomatic bacteriuria rule (pregnancy and pre-procedure only), nitrofurantoin-first empiric therapy, the Sandberg trial behind short-course pyelonephritis treatment, men's 7-day therapy from the JAMA non-inferiority trial, recurrent UTI prophylaxis sequencing — water, methenamine hippurate, oestrogen, cranberry, antibiotics — and catheter-associated infection rules.

high21 referencesUpdated 21 Aug 20269 min readVerification in progress

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Key points

Acute uncomplicated cystitis is a clinical diagnosis in non-pregnant women: one or more urinary symptoms carries roughly a 50% probability, and the combination of dysuria plus frequency without vaginal discharge or irritation raises it above 90% — treat empirically; no test can reliably rule the infection out.^[1]
Asymptomatic bacteriuria is treated only in pregnancy and before invasive urological procedures — never in healthy women, older adults, diabetics or catheterised patients; screening pregnant women with culture is a USPSTF grade B recommendation and treating it cuts pyelonephritis by around three-quarters.^[8]^[9]
Uncomplicated cystitis: nitrofurantoin first-line (modified-release 100 mg twice daily for 5 days); trimethoprim only where local resistance is low; fluoroquinolones are not for simple cystitis. Pyelonephritis in women can be treated orally — ciprofloxacin 7 days cured 97%, non-inferior to longer courses in the Sandberg trial.^[4]
Recurrent UTI sequencing starts honest and antibiotic-free where possible: increased water intake nearly halved episodes in a year-long RCT, methenamine hippurate was non-inferior to daily antibiotic prophylaxis (ALISCALS), vaginal oestrogen helps postmenopausal women, cranberry gives a modest risk reduction — continuous antibiotics remain effective but carry the side-effect cost.^[7]^[10]^[12]^[14]

Overview

Urinary tract infection spans two diseases wearing one name. The first — acute uncomplicated cystitis of healthy women — is common, self-limiting in many, diagnosable from history alone, and cured by short courses of narrow-spectrum antibiotics. The second — infection complicated by male anatomy, pregnancy, abnormal tract, stone, catheter or kidney involvement — demands cultures, longer or parenteral therapy, and a search for what made the host vulnerable. Confusing them drives both under-treatment and antibiotic overuse.^[5]

The organism is usually the patient's own bowel flora: uropathogenic Escherichia coli carrying fimbrial adhesins such as FimH and PapG climbs from perineum to bladder, binds urothelium, invades superficial cells and can form intracellular biofilm-like reservoirs that plausibly seed recurrence.^[19]^[20] Recurrence risk may also travel through the gut-bladder axis: women with recurrent UTI show gut microbiome depletion distinct from controls.^[18]

References21Show

[1]Bent S, Nallamothu BK, Simel DL, et al. Does this woman have an acute uncomplicated urinary tract infection? JAMA, 2002.PMID 12020306
[2]Hooton TM Clinical practice. Uncomplicated urinary tract infection N Engl J Med, 2012.PMID 22417256
[3]Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases Clin Infect Dis, 2011.PMID 21292654
[4]Sandberg T, Skoog G, Hermansson AB, et al. Ciprofloxacin for 7 days versus 14 days in women with acute pyelonephritis: a randomised, open-label and double-blind, placebo-controlled, non-inferiority trial Lancet, 2012.PMID 22726802
[5]Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America Clin Infect Dis, 2010.PMID 20175247
[6]Albert X, Huertas I, Pereiró II, et al. Antibiotics for preventing recurrent urinary tract infection in non-pregnant women Cochrane Database Syst Rev, 2004.PMID 15266443
[7]Smaill FM, Vazquez JC Antibiotics for asymptomatic bacteriuria in pregnancy Cochrane Database Syst Rev, 2019.PMID 31765489
[8]Nicolle LE, Gupta K, Bradley SF, et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America Clin Infect Dis, 2019.PMID 31506700
[9]US Preventive Services Task Force, Owens DK, Davidson KW, et al. Screening for Asymptomatic Bacteriuria in Adults: US Preventive Services Task Force Recommendation Statement JAMA, 2019.PMID 31550038
[10]Drekonja DM, Trautner B, Amundson C, et al. Effect of 7 vs 14 Days of Antibiotic Therapy on Resolution of Symptoms Among Afebrile Men With Urinary Tract Infection: A Randomized Clinical Trial JAMA, 2021.PMID 34313686
[11]Harding C, Mossop H, Homer T, et al. Alternative to prophylactic antibiotics for the treatment of recurrent urinary tract infections in women: multicentre, open label, randomised, non-inferiority trial BMJ, 2022.PMID 35264408
[12]Bakhit M, Krzyzaniak N, Hilder J, et al. Use of methenamine hippurate to prevent urinary tract infections in community adult women: a systematic review and meta-analysis Br J Gen Pract, 2021.PMID 34001538
[13]Hooton TM, Vecchio M, Iroz A, et al. Effect of Increased Daily Water Intake in Premenopausal Women With Recurrent Urinary Tract Infections: A Randomized Clinical Trial JAMA Intern Med, 2018.PMID 30285042
[14]Perrotta C, Aznar M, Mejia R, et al. Oestrogens for preventing recurrent urinary tract infection in postmenopausal women Cochrane Database Syst Rev, 2008.PMID 18425910
[15]Williams G, Stothart CI, Hahn D, et al. Cranberries for preventing urinary tract infections Cochrane Database Syst Rev, 2023.PMID 37947276
[16]Heltveit-Olsen SR, Arnljots ES, Sundvall PD, et al. Methenamine hippurate as prophylaxis for recurrent urinary tract infections in older women-a triple-blind, randomised, placebo-controlled, phase IV trial (ImpresU) Clin Microbiol Infect, 2025.PMID 40669691
[17]Stall NM, Kandel C, Reppas-Rindlisbacher C, et al. Antibiotics for delirium in older adults with pyuria or bacteriuria: A systematic review J Am Geriatr Soc, 2024.PMID 38895992
[18]Wang T, Wu G, Wang J, et al. Comparison of single-dose fosfomycin tromethamine and other antibiotics for lower uncomplicated urinary tract infection in women and asymptomatic bacteriuria in pregnant women: A systematic review and meta-analysis Int J Antimicrob Agents, 2020.PMID 32417205
[19]Anderson GG, Dodson KW, Hooton TM, et al. Intracellular bacterial communities of uropathogenic Escherichia coli in urinary tract pathogenesis Trends Microbiol, 2004.PMID 15337164
[20]García-García JD, Contreras-Alvarado LM, Cruz-Córdova A, et al. Pathogenesis and Immunomodulation of Urinary Tract Infections Caused by Uropathogenic Escherichia coli Microorganisms, 2025.PMID 40284582
[21]Worby CJ, Schreiber HL 4th, Straub TJ, et al. Longitudinal multi-omics analyses link gut microbiome dysbiosis with recurrent urinary tract infections in women Nat Microbiol, 2022.PMID 35505248