Recurrent urinary tract infection

Advice in this leaflet refers to men and women; this refers to biological sex registered at birth, therefore, advice given for women also applies to those who are of the female sex but have a different gender identity, and vice versa for men. A lower threshold for referral may be needed for those who have had gender identity surgery involving structural alteration of the urethra.

What is a recurrent urinary tract infection?¹²

Recurrent urinary tract infection (UTI) in adults is defined as two proven episodes within six months, or three within a year. Recurrent UTI in children is defined as ≥ 2 acute upper UTIs, ≥1 upper UTI with ≥1 lower UTI, or ≥3 episodes of lower UTI; no timescale is given over which these need to occur.

How common are recurrent urinary tract infections? (Epidemiology)

• Women have a lifetime risk of UTI of 1 in 2, and incidence increases with age.³

• UTI is uncommon in otherwise healthy young and middle-aged men; men account for only 20% of all UTIs. UTI incidence is higher in older men and is particularly common in those who are in institutional care and/or have a catheter.⁴

• Studies have shown that 25 - 44% of non-pregnant women with a first episode of cystitis will have a recurrence; in some cases it will be with the same organism. ⁵

• In children presenting with UTI before the age of 1 year, around three quarters will have a recurrence and after age 1 year, 45% of girls and 39% of boys will have a recurrence.⁶

Risk factors

There is evidence to suggest that genetic factors may play a part (usually through bacterial/vaginal mucosal adherence factors).⁵ Diabetes is also a predisposing factor.⁷

Causes of recurrent urinary tract infections (aetiology)

Escherichia coli has been shown to be responsible for around 75% of all UTIs, and over half of all complicated UTIs. ⁸Staphylococcus saprophyticus, Proteus mirabilis and Klebsiella species are the most common of the other organisms causing UTI.

Immunocompromise, diabetes and abnormalities of the urinary tract, and/or incomplete bladder emptying can predispose to UTI in a patient of any age or sex. Examples might include an indwelling catheter, neuropathic bladder, previous urinary tract surgery, vesico-ureteric reflux (VUR) or outflow obstruction.

Recurrent UTI in women³

Other risk factors can be considered as more likely to affect women either before or after the menopause.

In pre-menopausal women:

• Sexual intercourse (honeymoon cystitis).

• First UTI under the age of 15.

• History of UTI in the woman's mother.

In post-menopausal women:

• Atrophic urethritis and vaginitis.

• Urinary incontinence.

• Cystocele.

• Reduced functional status in women in institutional care.

Recurrent UTI in men⁴

• Abnormalities of the urinary tract as above.

• Age over 50 years.

• Incomplete bladder emptying (prostatic enlargement, chronic indwelling catheter).

• Previous urinary tract surgery.

• Immunocompromise.

• Not being circumcised.

• Having penetrative sex (vaginal or anal).

• Recent hospital admission.

Recurrent UTI in children²

• Any condition that leads to urinary stasis (VUR, renal calculi, obstructive uropathy), family history of VUR or voiding disorders, poor urine flow for example, due to phimosis.

• Constipation.

• Impaired immune function.

• Sexual abuse.

• Impaired renal function.

Symptoms of recurrent urinary tract infections (presentation)

• Recurrent UTI symptoms include:

  • Dysuria.

  • Frequency.

  • Urgency.

  • Nocturia.

  • Haematuria.

  • Suprapubic discomfort.

• Signs may include:

  • Suprapubic tenderness.

  • Cloudy or foul-smelling urine.

  • In the elderly, incontinence, confusion, anorexia, fever, shock.

Diagnosing recurrent urinary tract infections (investigations)^23491011

Primary care - urine samples

• MSU culture, urine microscopy:

  • MSU is recommended in cases of recurrent UTI, due to the increased likelihood of resistant organisms.

  • In children, a clean catch urine sample is the recommended method for urine collection. This is much easier in toilet-trained children.

Further investigation and referral

• Those of either sex with haematuria should be referred urgently, on the suspected cancer pathway if there is unexplained visible haematuria over the age of 45, or unexplained non-visible haematuria with dysuria or a raised white cell count over the age of 60.

• All men and children with recurrent UTI should be referred to secondary care.

• Children with recurrent UTI should have an ultrasound during the acute infection if aged <6 months; realistically, given the usual speed of access from primary care, this would have to be via an acute referral to paediatrics. Children aged ≥ 6 months should have an ultrasound within six weeks. Investigation in secondary care may include dimercaptosuccinic acid (DMSA) scan or a micturating cystogram.

• Only a small fraction of women with recurrent UTIs will have a relevant structural or functional abnormality of the urinary tract. The National Institute for Health and Care Excellence (NICE) suggests that we consider an ultrasound, but does not give any guidance on further investigation, or on what features seen on ultrasound should prompt referral. The 2024 Academy of Medical Royal Colleges (AoMRC) guidance has a stated aim to complement the NICE guidance in terms of when to refer women with recurrent UTIs. Its advice is as follows, and applies to non-pregnant adult women.

  • All women with recurrent UTI should have an ultrasound of the renal tract, including measurement of post-micturition volume. Referral should be done if the scan shows hydroureter, hydronephrosis, stones in the bladder or ureter, obstructive stones anywhere in the renal tract, or a post-micturition volume >150ml.

  • Women who meet any of the following criteria should also be referred:

    • Prior urinary tract surgery, pelvic organ prolapse surgery or trauma.

    • Prior abdominopelvic malignancy.

    • Visible and non-visible haematuria after resolution of infection.

    • Urea-splitting bacteria on culture (for example, Proteus, Yersinia) in the presence of a stone, or atypical infections (for example, tuberculosis, anaerobic bacteria)

    • Bacterial persistence or on-going lower urinary tract symptoms after sensitivity-based therapy.

    • Pneumaturia or faecaluria.

    • Voiding symptoms (straining, weak stream, intermittency, hesitancy).

  • Women who have none of the above factors should be discussed with secondary care via the advice and guidance system (or local equivalents), only if symptoms persist despite optimal primary care management.

• European guidelines (aimed at urologists) give a similar message, advising that an extensive workup is not routinely recommended but that factors such as suspected renal calculi, outflow obstruction, interstitial cystitis or urothelial cancer should prompt investigations which may include a CT scan, cystoscopy or excretory urography.

Recurrent UTI treatment^{1 3101213}

Treatment for women

Self-care and hygiene advice

• Give advice on self-care and hygiene:

  • NICE advises that some people may want to try D-mannose or cranberry products, but that evidence for cranberry products is uncertain (with no evidence of benefit for older women) and that both have a significant sugar content. Evidence for D-mannose is based on it being used as 200ml of 1% solution once daily in the evening and it can be bought over the counter. They also note that evidence is unclear as to whether probiotics reduce the risk of further UTI in those with recurrent UTI.

  • NICE advises that evidence is inconclusive as to whether the use of probiotics will reduce the risk of further UTI in people with recurrent UTI. European guidelines state that 'probiotics containing L. rhamnosus GR-1, L. reuteri B-54 and RC-14, L. casei shirota, or L. crispatus CTV-05 are effective for vaginal flora restoration and have shown a trend towards prevention of recurrent UTIs', but that evidence for this is weak.

  • NICE advises that self-care should also include drinking 1.5L of water per day (if no contraindications), the avoidance of douching and occlusive underwear, wiping from front to back after defecation and avoiding the delay of urination, both routinely and after intercourse.

• Consider vaginal oestrogen for women in the menopause or perimenopause if self-care measures are not appropriate or not effective. There is minimal systemic absorption and this can be given as a cream, gel, tablet, pessary or ring, depending on the woman's preference. Consult the 2024 update of the NICE guidance on menopause (NG23) before giving this to a woman who has a history of breast cancer; NICE advises that it is likely to be safe for those who had an oestrogen receptor negative cancer, but that safety is unknown where the cancer was oestrogen receptor positive. The use of tamoxifen would help to mitigate any increased risk. Vaginal oestrogen shouldn't be used in those taking an aromatase inhibitor.

• Systemic HRT should not be used specifically to reduce the risk of recurrent UTI.

• In the case of a relapse, send an MSU before starting antibiotics. Use clinical judgment to decide whether to make an immediate, self-initiated short course of antibiotics available to the woman.

Treat the individual UTI as per NICE guidance.

Further management for women with recurrent UTI who are not pregnant

• Consider a trial of antibiotic prophylaxis only if behavioural and personal hygiene measures, and vaginal oestrogen (in postmenopausal women), are ineffective or inappropriate.

• Ensure that any current UTI has been adequately treated; then consider single-dose antibiotic prophylaxis (trimethoprim 200mg or nitrofurantoin 100mg) for use when exposed to an identifiable trigger (for example, coitus).

• Second choice antibiotics for single-dose prophylaxis are amoxicillin 500mg or cefalexin 500mg.

Take account of:

• The severity and frequency of previous symptoms.

• The risk of developing complications.

• Previous urine culture and susceptibility results.

• Previous antibiotic use, which may have led to resistant bacteria.

• The woman's preferences for antibiotic use.

When single-dose antibiotic prophylaxis is given, give advice about:

• How to use the antibiotic.

• Possible side-effects - for example, diarrhoea and nausea.

• Returning for review within six months.

• Seeking medical help if there are symptoms of an acute UTI.

If self-care, vaginal oestrogen (if appropriate) and single dose antibiotic prophylaxis have not been effective, the next step is to consider either daily dose antibiotic prophylaxis, or methenamine hippurate.

Methenamine hippurate

The NICE guidance gives this as unlicensed, but as of February 2025 it is listed in the BNF for management of prophylaxis of uncomplicated lower urinary-tract infection. It is unlicensed for prophylaxis of recurrent upper UTI or recurrent complicated lower UTI. A complicated lower UTI is where there is a predisposing factor towards recurrent infection, or a predisposing factor which may make treatment ineffective. These include structural urinary tract abnormalities, a particularly virulent organism, immunocompromise or impaired renal function.

NICE advises that we seek specialist advice if considering using methenamine hippurate during pregnancy, in men, in children, or in an unlicensed way as above.

Patients taking methenamine hippurate should be advised to avoid over the counter sachets which make urine more alkaline, as these reduce the effectiveness of methenamine hippurate. Treatment should be reviewed at six months and then at least annually.

Daily antibiotic prophylaxis

When considering a trial of daily antibiotic prophylaxis, take account of:

• Any further investigations (for example, ultrasound) that may be needed to identify an underlying cause.

• The severity and frequency of previous symptoms.

• The risks of long‑term antibiotic use.

• The risk of developing complications.

• Previous urine culture and susceptibility results.

• Previous antibiotic use, which may have led to resistant bacteria.

• The woman's preferences for antibiotic use.

Antibiotic options in non-pregnant women

• First choice:

  • Trimethoprim 100 mg at night.

  • Nitrofurantoin (if eGFR>45 ml/minute) 50 - 100 mg at night.

• Second choice:

  • Amoxicillin 250 mg at night.

  • Cefalexin 125 mg at night.

Actions for those who get post-coital UTI

• Urinate after intercourse.

• Consider single dose antibiotics post intercourse.

Treatment for men ⁴

There is little high-quality evidence to inform this section, due to the relative rarity of UTI in men, compared with women.

• Consider alternative diagnoses:

  • Acute prostatitis.

  • Bladder or renal malignancy (particularly if haematuria is present).

  • Epididymitis.

  • Pyelonephritis.

  • Sexually transmitted infections.

  • Urethritis.

  • Other urological disorders such as stones or benign enlargement of the prostate.

• Treat each episode as acute lower UTI (assuming that another diagnosis is not suspected) and arrange a urine culture before treating.

• Prescribe an antibiotic to be taken for seven days. Trimethoprim or nitrofurantoin are usual first-line choices, as per non-pregnant women.

• Recurrent cystitis in a man is likely to be secondary to associated conditions - for example, prostatitis, prostatic hyperplasia, calculi in the genitourinary tract, or VUR.

• Refer men with recurrent UTI for investigation for underlying causes and for advice about prophylactic antibiotics where required.

Treatment for children

General principles

• Treat urinary tract infection as per NICE guidance.¹⁴

• Children with a high risk of serious illness and/or younger than 3 months should be referred immediately to secondary care. This should be assessed in accordance with NICE guidance on feverish illness in children (see Further Reading, below).

• Do not delay treatment if the sample cannot be obtained and the infant or child is at high risk of serious illness.

• Treat each episode of acute UTI the same as a first episode.

NICE guidelines advise, in order to try to prevent recurrence in children who have had a UTI, that:

• Dysfunctional elimination syndromes and constipation should be addressed.

• Adequate fluid intake should be encouraged.

• Children should have ready access to clean toilets when required and should not be expected to delay voiding.

The principles of daily antibiotic prophylaxis discussed above also apply for children, but this should only be done after specialist advice. See the BNF or NICE guidelines for doses.

If antibiotics are to be prescribed, the following options should be considered:

Complications of recurrent urinary tract infections

Most people will recover fully with treatment. However, recurrent UTI is a risk factor for pyelonephritis, which can cause renal scarring. This in turn can lead to hypertension and impaired renal function.