Purpose and audience

This guideline provides recommendations based on current evidence for best practice in the diagnosis and management of suspected bacterial lower urinary tract infection in adult women. It replaces SIGN 88: Management of suspected bacterial urinary tract infection in adults which was first published July 2006 and updated in July 2012. This guideline includes younger women aged 16–64 years; older women aged 65 years and over; and women of any age using an indwelling, intermittent or suprapubic catheter. It also includes the diagnosis and management of recurrent UTI in these groups.

The decision to focus on guidance for managing UTI symptoms in non-pregnant women of all ages was based on the burden of infection being in this population and the potential complicated nature of UTI in other populations.

The guideline is aimed primarily at healthcare professionals in primary-care settings, as the majority of non-pregnant women with symptoms of UTI will present in the community. Women with symptoms of UTI account for a significant proportion of acute presentations to GP practices and out-of-hours services, and evolution of services in Scotland means a proportion will also now be managed by community pharmacists.

For more information on background and aims see full guideline section Chapter 1.


The European Association of Urology categorises urinary tract infections based on the clinical presentation of the UTI, the anatomical level of the UTI, the grade of severity of the infection, the categorisation of risk factors and availability of appropriate antimicrobial therapy. Details of their classification of UTI is shown in the table below: 29

Uncomplicated UTIs Acute, sporadic or recurrent lower (uncomplicated cystitis) and/or upper (uncomplicated pyelonephritis) UTI, limited to non-pregnant women with no known relevant anatomical and functional abnormalities within the urinary tract or comorbidities.
Complicated UTIs All UTIs which are not defined as uncomplicated, meaning UTIs in a patient with an increased chance of a complicated course: ie all men, pregnant women, patients with relevant anatomical or functional abnormalities of the urinary tract, indwelling urinary catheters, renal diseases, and/or with other concomitant immunocompromising diseases, for example diabetes.
Recurrent UTIs Recurrences of uncomplicated and/or complicated UTIs, with a frequency of at least three UTIs/year or two UTIs in the last six months.
Catheter-associated UTIs Catheter-associated urinary tract infection (CA-UTI) refers to UTIs occurring in a person whose urinary tract is currently catheterised or who has had a catheter in place within the past 48 hours.

Recurrent UTI may be due to relapse/persistence or reinfection.30

  • Relapse or persistence is recurrent UTI with the same strain of organism. Relapse/persistence is the likely cause if UTI recurs (or fails to be eradicated) within a short period (within two weeks) after sensitivity-adjusted treatment.
  • Reinfection is recurrent UTI with a different strain or species of organism or the same organism more than two weeks after treatment.

Empirical antimicrobial treatment occurs when the prescriber has not yet identified the bacteria causing the infection and does not know the suspected bacteria’s susceptibility to antibiotics.

Key to recommendations

Some recommendations can be made with more certainty than others. The wording used in the recommendations in this guideline denotes the certainty with which the recommendation is made (the ‘strength’ of the recommendation).

The ‘strength’ of a recommendation takes into account the quality (level) of the evidence. Although higher-quality evidence is more likely to be associated with strong recommendations than lower-quality evidence, a particular level of quality does not automatically lead to a particular strength of recommendation.

Other factors that are taken into account when forming recommendations include: relevance to the NHS in Scotland; applicability of published evidence to the target population; consistency of the body of evidence, and the balance of benefits and harms of the options.

Recommendation RFor ‘strong’ recommendations on interventions that ‘should’ be used, the guideline development group is confident that, for the vast majority of people, the intervention (or interventions) will do more good than harm. For ‘strong’ recommendations on interventions that ‘should not’ be used, the guideline development group is confident that, for the vast majority of people, the intervention (or interventions) will do more harm than good.

Recommendation RFor ‘conditional’ recommendations on interventions that should be ‘considered’, the guideline development group is confident that the intervention will do more good than harm for most patients. The choice of intervention is therefore more likely to vary depending on a person’s values and preferences, and so the healthcare professional should spend more time discussing the options with the patient.

Good practice points
Good practice point tickRecommended best practice based on the clinical experience of the guideline development group.

The evidence base

Systematic literature review
The evidence base for this guideline was synthesised in accordance with SIGN methodology.  A systematic review of the literature was carried out using an explicit search strategy devised by a SIGN Evidence and Information Scientist. Databases searched include Medline, Embase, Cinahl, CENTRAL, PsycINFO and the Cochrane Library. The year range covered was 2003–2018. Internet searches were carried out on various websites for relevant guidelines. The main searches were supplemented by material identified by individual members of the development group. Each of the selected papers was evaluated by two Evidence and Information Scientists using standard SIGN methodological checklists before conclusions were considered as evidence by the guideline development group.

The search strategies are available on the SIGN website.

Literature search for patient issues
At the start of the guideline development process, a SIGN Evidence and Information Scientist conducted a literature search for qualitative and quantitative studies that addressed patient issues of relevance to diagnosis and management of suspected bacterial UTI. Databases searched include Medline, Embase, Cinahl and PsycINFO, and the results were summarised by the SIGN Patient Involvement Advisor and presented to the guideline development group.

Literature search for cost-effectiveness evidence
The guideline development group identified key questions with potential cost-effectiveness implications, based on the following criteria, where it was judged particularly important to gain an understanding of the additional costs and benefits of different treatment strategies:

  • treatments which may have a significant resource impact
  • opportunities for significant disinvestment or resource release
  • the potential need for significant service redesign
  • cost-effectiveness evidence could aid implementation of a recommendation.

A systematic literature search for economic evidence for these questions was carried out by a SIGN Evidence and Information Scientist covering the years 2008–2018. Databases searched include Medline, Embase and NHS Economic Evaluation Database (NHS EED). Each of the selected papers was evaluated by a Health Economist, and considered for clinical relevance by guideline group members.

Interventions are considered to be cost effective if they fall below the commonly-accepted UK threshold of £20,000 per QALY.

For recommendations for research, see section 9.2 of the full guideline.

Development of the guideline

SIGN is a collaborative network of clinicians, other healthcare professionals and patient organisations and is part of Healthcare Improvement Scotland. SIGN guidelines are developed by multidisciplinary groups of practising healthcare professionals using a standard methodology based on a systematic review of the evidence. Further details about SIGN and the guideline development methodology are contained in ‘SIGN 50: A Guideline Developer’s Handbook’.

This guideline was developed according to the 2015 edition of SIGN 50.


AMR antimicrobial resistance
ASB asymptomatic bacteriuria
BIA budget impact assessment
CA-ASB catheter-associated asymptomatic bacteriuria
CA-UTI catheter-associated urinary tract infection
CDI Clostridioides difficile infection
CFU colony-forming unit
CI confidence interval
E. coli Escherichia coli
eGFR estimated glomerular filtration rate
GMC General Medical Council
GP general practitioner
IDSA Infectious Diseases Society of America
IQR interquartile range
IRR incidence rate ratio
K. pneumoniae
Klebsiella pneumoniae
LE leukocyte esterase
LR- negative likelihood ratio
LR+ positive likelihood ratio
LUTI lower urinary tract infection
MA marketing authorisation
MHRA Medicines and Healthcare Products Regulatory Agency
MIC minimum inhibitory concentration
MRSA methicillin-resistant Staphylococcus aureus
NHS National Health Service
NHS EED NHS Economic Evaluation Database
NICE National Institute for Health and Care Excellence
NNT number needed to treat
NS not significant
NSAID non-steroidal anti-inflammatory drug
OR odds ratio
PAC proanthocyanidin
QALY quality-adjusted life year
RCT randomised controlled trial
RR relative risk
SAPG Scottish Antimicrobial Prescribing Group
SIGN Scottish Intercollegiate Guidelines Network
SMC Scottish Medicines Consortium
SUTIN Scottish Urinary Tract Infection Network
UTI urinary tract infection


This guideline was issued in 2020 and will be considered for review in three years. The review history, and any updates to the guideline in the interim period, will be noted in the update report, which is available in the supporting material section for this guideline on the SIGN website: www.sign.ac.uk.

Comments on new evidence that would update this guideline are welcome and should be sent to the SIGN Executive, Gyle Square, 1 South Gyle Crescent, Edinburgh, EH12 9EB (email: sign@sign.ac.uk).

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The content within this app/website is based on current evidence and best practice, however it is intended to be applied alongside sound clinical judgement.  As such, Healthcare Improvement Scotland is not responsible or liable for any diagnosis or management decision made on the basis of the information provided via this app/website.

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Scottish Intercollegiate Guidelines Network (SIGN).  SIGN 160: Management of suspected bacterial lower urinary tract infection in adult women.  Edinburgh: SIGN; 2020. [cited 08 Feb 2021]  Available from: 


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SIGN (Scottish Intercollegiate Guidelines Network): SIGN was formed in 1993. Its objective is to improve the quality of health care for patients in Scotland by reducing variation in practice and outcome, through the development and dissemination of national clinical guidelines containing recommendations for effective practice based on current evidence.

The membership of SIGN includes all the medical specialties, nursing, pharmacy, dentistry, professions allied to medicine, patients, health service managers, social services, and researchers. The work of SIGN is supported by an Executive.

SIGN is part of the Evidence Directorate of Healthcare Improvement Scotland and core funding from Healthcare Improvement Scotland supports the SIGN Executive, and expenses and costs associated with guideline development projects. SIGN is editorially independent from Healthcare Improvement Scotland and the Scottish Government which ultimately funds Healthcare Improvement Scotland.

See section 10.2 of the guideline for details of the Guideline Development Group membership.

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DHI leads and manages the national Decision Support Programme on behalf of Scottish Government, as a core objective within Scotland’s Digital Health and Care Strategy. The app and website have been built using the Right Decision Service tools which DHI has developed as a key deliverable for the national programme.

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Tactuum Ltd –Tactuum is a software company based in Glasgow, with an office in the US. Tactuum’s mission is to improve healthcare services through the delivery of digital services supporting healthcare providers and patients. Tactuum provides the technology and digital expertise to deliver Right Decision Service tools for the National Decision Support Programme.


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29 European Association of Urology. Urological Infections guideline. [cited 20 Mar 2020]. Available from url: https://uroweb.org/guideline/urological-infections/

Dason S, Dason JT, Kapoor A. Guidelines for the diagnosis and management of recurrent urinary tract infection in women. Can Urol Assos J 2011;5(5):316-22.  Available at url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202002/