Recurrent Urinary Tract Infections in Women

Urinary tract infections (UTIs) are one of the most frequently occurring bacterial infections in women, and at least 50-60% of women will develop a UTI in their lifetime. The most common organism causing UTIs is the bacteria Escherichia coli. The urinary tract is usually a sterile environment. However, bacteria may transfer from the perianal region, causing a UTI and leading to symptoms such as painful urination and increased urinary urgency.

The definition of a recurrent UTI (rUTI) is having three or more UTIs showing positive cultures during a 12-month period or at least two UTIs showing positive cultures in the previous six months.

UTIs can be classified into various categories, including uncomplicated infections, where the urinary tract is structurally and physiologically normal, and complicated infections where there are abnormalities of the urinary tract. Early investigations, including cystoscopy and urinary tract imaging, should be considered for women with complicated UTIs and those with uncomplicated UTIs who also show atypical features or are not responding to treatment. UTIs can also be classified as being unresolved, where therapy fails due to bacterial resistance or due to infection by two different bacteria; reinfection, where the infection clears after treatment but then the same organism regrows at least two weeks after therapy or a different microorganism grows during any period of time; and relapse, when the same microorganism causes a UTI within two weeks of therapy. Accurately diagnosing and categorising a UTI can help correct complicating factors that predispose someone to an rUTI and guide treatment. Recurrences of UTIs generally occur within three months of the original infection, and 80% of rUTIs are reinfections. Common risk factors for rUTIs are listed in Table 1.

Table 1: Risk factors for rUTIs

General non-antibiotic strategies to prevent rUTIs include drinking plenty of water in order to urinate more frequently to help flush bacteria from the bladder, cleaning the genital areas prior to and after having sex, wiping from front to back to reduce the spread of E.coli from the perigenital area to the urethra, and avoiding multiple sexual partners. Avoidance of products such as spermicides, diaphragms, vaginal douching, bubble bath liquids, bath oils, deodorant sprays or soaps is recommended as they may irritate the vaginal and urethral areas and encourage colonisation of bacteria within the urinary tract or alter the vaginal flora, which could lead to a UTI.

The Therapeutic Guidelines recommend antibiotic prophylaxis for rUTIs in those who have frequent symptomatic infections (i.e. two or more infections within six months, or three or more infections within 12 months). Antibiotic prophylaxis strategies (see Table 2) are effective ways of managing rUTIs and include either continuous prophylaxis or intermittent postcoital prophylaxis. Acute self-treatment may also be considered. Urine culture and sensitivity analysis should be performed at least once while the patient is symptomatic, and a midstream technique needs to be used when collecting the urine sample in order to reduce the risk of vaginal and skin contamination. The results of urine cultures confirm the diagnosis, provide antibiotic sensitivities, allow for targeted treatment of the UTI and guide the choice of antibiotics for prophylaxis.

Table 2: Antibiotic regimes for recurrent UTIs in non-pregnant women

Urine culture and sensitivity results should guide the choice of antibiotic wherever possible, and regional antibiotic resistance patterns, patient preferences and tolerance should also be considered. If UTIs recur despite prophylactic treatment, specialist expert advice should be sought.

Adjunct treatments may also be considered. Intravaginal estrogen in post-menopausal women has been shown to have beneficial effects on vaginal flora and reduces the incidence of rUTIs in small randomised controlled trials. Cranberry products did not show sufficient evidence of benefit in preventing UTIs and thus are not recommended for the prevention of UTIs. Methenamine hippurate has a bacteriostatic effect in the urine and may reduce the incidence of symptomatic UTIs in women without urinary tract abnormalities. However, evidence for the prevention of UTIs is poor and inconsistent. It has also not been shown to be effective for the prevention of UTIs in those with urinary tract abnormalities. D-mannose is thought to have antibacterial activity by inhibiting bacteria’s adherence to urothelial cells. Limited studies demonstrate a reduction in the rate of UTI recurrence in women. However, further studies are required. Other treatments, such as probiotics, immunostimulants, vaccines, and acupuncture, have been investigated. However, further evaluation is required.