• Question: If a patient is started on prophylaxis for UTI but subsequently has an acute infection, and the MSSU demonstrates resistance to the prophylactic antibiotic - is there still merit in continuing? I am aware that you will have resistance for a period anyway after taking an antibiotic which is why I think some folk used to 'cycle' antibiotics but just wondered what the likely benefits of the prophylaxis would be give this.

    Asked by athomson11 to Thamarai, Rose, Paul, Michael, Martin, , , Jeroen, Elizabeth, Cliodna, Chris, Andrew, Alastair, Adam on 18 Nov 2015.
    • Photo: Michael Moore

      Michael Moore answered on 18 Nov 2015:


      I think it is not uncommon for women to get breakthrough infection when on antibiotic prophylaxis and the bug will often be resistant to the prescribed antibiotic. If they are symptomatic then you would treat as appropriate and I would usually switch prophylactic agent. You do need to be more cautious with nitrofurantoin since it won’t work so well with a reduced eGFR and longer term use can lead to liver problems and pulmonary fibrosis. So one of the limitation of using long term prophylaxis is ‘running out’ of appropriate antibiotics. In a systematic review (Costelloe) of antibiotic resistance it was found that there was higher carriage of resistant urinary bugs even 12 months after antibiotic exposure- so this could be a real problem.

    • Photo: Elizabeth Beech

      Elizabeth Beech answered on 18 Nov 2015:


      Michael – There was discussion in a related question about methenamine (Hiprex) for prophylaxis for UTI, and I mentioned that some guidelines now include this as a ‘less worse’ option than low dose antibiotic. What is your opinion? Have you any experience of using it? (The Cochrane review was poor evidence)

    • Photo: Marco

      Marco answered on 19 Nov 2015:


      Once started the ‘cycle’ of antibiotics, I would continue until it is finished to avoid building up resistance in the “microbial community”, but wait for answers from more experts, I am an economist after all 😉

    • Photo: Cliodna McNulty

      Cliodna McNulty answered on 23 Nov 2015:


      I agree I would switch agents for treatment,
      and then go to another agent for prophylaxis if possible. As development of resistance is a problem, it may be better to consider standby antibiotics or antibiotics just after intercourse.

      SIGN guidance indicates that cranberry products can be effective

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