Recurrent urinary tract infection (rUTI) is defined as two or more UTIs over six months, or three or more UTIs over 12 months. The recurrence can be reinfection (clear sample after treatment, recurrence often with a different organism) or persistence (no clear sample, same organism). Non-antibiotic prophylaxis should be considered to reduce the risk of antibiotic-related complications or resistance.
While any UTI in a male is a red flag event and may indicate abnormal structure or function of the urinary tract, UTIs in women are very common. In young women there is often no clear predisposing factor.
Even with rUTI, a large portion of patients may be young, immune-competent women with structurally normal urinary tracts. In one study, 27% of young university-age women with their first UTI experienced at least one recurrence within the following six months. Recurrence is more common as women age. In women over 55 some 53% report UTI recurrence.
First line therapy for a symptomatic UTI is a single course of appropriately targeted antibiotics. If the infection recurs, there may be a role for prophylaxis after the active infection is treated.
Long-term antibiotic prophylaxis with rotating low-dose antibiotics over six months is effective but can damage the intestinal flora and promote the development of bacterial resistance.
A simple option is urinary sterilisers such as methanamine (Hiprex). This is a urinary steriliser that is converted to formaldehyde in the urine. It does not lead to bacterial resistance and has a low side effect profile. There is some evidence that it is effective as a short-term non antibiotic prophylaxis where the urinary tract anatomy is normal. It works best in acidic urine so is often taken in combination with vitamin C while avoiding urinary alkalinisers.
Another option are drugs that replenish the bladders glycosominoglycan (GAG) layer such as hyaluronic acid plus chondroitin (e.g. iAluril). This is an intravesical therapy that replenishes the GAG layer in the bladder, which is a natural defence against UTI. Meta-analysis has shown a reduction in 2.6 UTI episodes per patient per year with these agents. These results are likely conservative because in all but one study the comparator was prophylactic antibiotics not placebo.
Vaginal estrogen replacement can be beneficial in post-menopausal women without specific contraindications.
Emerging vaccines and immunotherapies show promise. Uromune is a vaccine for recurrent UTIs administered sublingually as a spray, with two pumps every 24 hours over three months. It contains a suspension of inactive whole bacteria (E coli, K pneumoniae, P vulgaris and E faecalis). This isn’t available in Australia, but its effect has been demonstrated in multiple studies. Up to 90% of patients who had previously suffered rUTI reported a reduction to 0-1 UTIs over the 12 months after starting the treatment.
- Recurrent UTIs are more common in women, increasing with age
- Long-term antibiotic prophylaxis can cause resistance
- Consider non-antibiotic prophylaxis
References available on request.
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Author competing interests: None to disclose.
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