• Question: When considering which antibiotic to choose (empirically) for UTI how far back in time should you be going in relation to considering previous resistance patterns for that patient

    Asked by athomson11 on 18 Nov 2015.
    • Photo: Michael Moore

      Michael Moore answered on 18 Nov 2015:

      The systematic review (Costelloe BMJ 2010) suggested that resistance may persist for up to 12 months after antibiotic exposure- so I think looking back 12 months would be sensible

    • Photo: Andrew Hayward

      Andrew Hayward answered on 18 Nov 2015:

      Although the increased of resistance can persist for a year after an antibiotic this risk drops fastest in the first few months after a prescription.

    • Photo: Marco Boeri

      Marco Boeri answered on 19 Nov 2015:

      I would agree with 6 to 12 months, but I do not consider myself an expert on this.

    • Photo: Cliodna McNulty

      Cliodna McNulty answered on 23 Nov 2015:

      Yes I agree with the others that risk can persist for 6-12 months, but the risk is higher in the first few months, and is obviously partly dependant on the infection you are considering, age of the patient and risk factors for resistance (travel abroad, post hospitalisation, recurrent infections, etc).

      When we undertook a porspective study on the clinical siginificance of resistance in UTI. 50% of the women (aged 18-64) who reconsulted in the first week after being given empirical trimethoprim had a resistant organism grown on culture. However those with just 2 episodes of UTI in the previous year were not significantly more likely to have a resistant organism.
      I suggest you could use mosaic prescribing in UTI, alternating between nitrofurantoin and trimethoprim first line for acute uncomplicated UTI in younger women.