Primary care antimicrobial stewardship
: Impact on prescribing and resistance

  • Virginia Hernandez Santiago

    Student thesis: Doctoral ThesisDoctor of Philosophy


    Background: Antimicrobial resistance is an increasing world-wide public health concern, with antimicrobial use described as one of the main drivers. Most antimicrobial prescribing occurs in primary care which is therefore a key target for antimicrobial stewardship. This thesis examines antimicrobial stewardship in primary care using systematic review of published trials and time-series evaluation of a system-wide multi-faceted intervention implemented in Tayside, Scotland.

    Methods: (1) Systematic review and meta-analysis of published randomized-controlled trials to evaluate the impact on antimicrobial prescribing of stewardship interventions in community settings. (2) Segmented regression analysis of time-series data to examine the impact of the Tayside intervention on population antimicrobial prescribing, and on outcomes (resistance, length of stay, and 30-day mortality) in people admitted to hospital with community-associated coliform bacteraemia.

    Findings: The systematic review included 63 trials, half of which involved educational interventions. The most effective type of intervention was the use of point of care tests, followed by decision support, followed by education and multi-faceted interventions. The Tayside intervention was associated with very large reductions in prescribing of targeted broad-spectrum antimicrobials of >30% at one year post-intervention increasing to up to 74% reduction at three years. Reductions in broad-spectrum resistance in community-associated coliform bacteraemia were observed for fluoroquinolones (34.7% reduction three years post-intervention) and cephalosporins (-48.3%) but there was no significant change in co-amoxiclav resistance. There was no evidence of an increase in bacteraemia admission rates or mortality, but length of stay significantly fell in people with bacteraemia. However, the intervention was also associated with increases in prescribing of other antimicrobials (amoxicillin, trimethoprim, nitrofurantoin, and doxycycline), and significant increases in coliform bacteraemia resistance to amoxicillin were also observed.

    Conclusions: Most types of stewardship intervention reduce antimicrobial prescribing in primary care, and this study adds evidence of improved antimicrobial resistance to targeted antimicrobials in important infections at the population level.
    Date of Award2019
    Original languageEnglish
    SponsorsChief Scientist Office
    SupervisorBruce Guthrie (Supervisor) & Charis Marwick (Supervisor)

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