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Urinary tract infection (UTI) is the presence and multiplication of microorganisms in one or more structures of the urinary tract with organisms invading the surrounding tissue (1).

Infections of the urinary tract are very common accounting for 1-3% of all consultations in general practice per year (2). It is accountable for the second most common clinical indication for empirical antimicrobial therapy in primary and secondary care (3).

It is much more common in women than in men (2). Most women will have at least one urinary tract infection in their lives. It is more unusual in men (in men between 20 and 60 the incidence is less than <1%) who have longer urethras and should be investigated for underlying pathology e.g. – prostate pathology (2).

UTI includes a variety of clinical syndromes,

  • acute and chronic pyelonephritis (kidney and renal pelvis)
  • cystitis (bladder)
  • urethritis (urethra)
  • epididymitis (epididymis)
  • prostitis (prostate) (1)

The rate of incidence

  • is equal between the sexes in the first year of life
  • in elderly it is between 1 and 3 %
  • increases with age, co-existent disease or institutional care (2).

Lower UTI (3)

  • in most cases, managing lower UTI will require antibiotic treatment. However, acute, uncomplicated lower UTI in non-pregnant women can be self-limiting and for some women delaying antibiotic treatment with a back-up prescription to see if symptoms will resolve without antibiotic treatment may be an option
  • main complication of lower UTI is ascending infection leading to upper UTI (acute pyelonephritis)
    • most episodes of acute pyelonephritis are uncomplicated and result in no residual kidney damage - complications can include impaired renal function or renal failure, septicaemia and preterm labour in pregnancy
      • in men, prostate involvement is common, which may lead to acute prostatitis, chronic bacterial prostatitis or a prostatic abscess; urinary stones are also a possibility (4)
      • in children, UTIs can lead to renal scarring, but more often this is preceded by acute pyelonephritis rather than lower UTI, and it is more common in children with vesicoureteral reflux (5)

Escherichia coli causes most UTIs in men (6) and this is the cause in 70% to 95% of uncomplicated cases in women, with Staphylococcus saprophyticus being the cause in 5% to 20% of cases (7)

Asymptomatic bacteriuria, where there is significant bacteriuria but no symptoms or signs of infection, is not routinely screened for or treated, except if it is considered a risk factor, such as in pregnant women


  1. Health Protection Agency (HPA) 2009. National standard method. Investigation of urine
  2. London Deanery. The assessment and management of urinary tract infections in women in general practice
  3. Scottish Intercollegiate Guidelines Network (SIGN) 2020. Management of suspected bacterial urinary tract infection in adult women
  4. Smithson A, Ramos J, Niño E, et al. Characteristics of febrile urinary tract infections in older male adults. BMC Geriatr. 2019 Nov 29;19(1):334.
  5. Larcombe J. Urinary tract infection in children: recurrent infections. BMJ Clin Evid. 2015 Jun 12;2015
  6. Schaeffer AJ. Infections of the urinary tract. In: Walsh PC, ed. Campbells' urology, 8th ed. Philadelphia, PA: Saunders; 2002.
  7. Concia E, Bragantini D, Mazzaferri F. Clinical evaluation of guidelines and therapeutic approaches in multi drug-resistant urinary tract infections. J Chemother. 2017 Dec;29(supl 1):19-28.

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