Do antibiotic stewardship interventions in primary care have an effect on antimicrobial resistance of Escherichia coli bacteraemia in England? An ecological analysis of national data between 2013-2018

Abstract

Background: We sought to evaluate the effectiveness of a national antimicrobial stewardship intervention, the Quality Premium (QP), on broad-spectrum antibiotic prescribing and Escherichia coli bacteraemia resistance to broad-spectrum antibiotics in England. Methods: We used longitudinal data on patients registered with a general practitioner in the English National Health Service and patients with E. coli bacteraemia notified to the national mandatory surveillance programme between January 2013-December 2018.We conducted an ecological analysis using interrupted time series (ITS) analyses and generalised estimating equations (GEE) to estimate the change in broad-spectrum antibiotics prescribing over time and change in the proportion of E. coli bacteraemia cases where the causative bacteria were resistant to each antibiotic individually or to at least one of the five antibiotics, after implementation of the QP. Findings: Following the implementation of the QP in April 2015, we observed an immediate downward step-change in broad-spectrum antibiotic prescribing incidence rate of 0.867per 1000 patients (95% CI: 0.837 to 0.898, p<0·001). We found that the pre-intervention slope for total antibiotic usage was an IRR of 1.002(CI: 1.000to 1.004, p-value=0.046). The change in slope for total antibiotic usage was an IRR of 0.993(CI: 0.991to 0.995, p<0·001). We also observed a downward step-change in resistance rate of 0.947 per 1000 E. coli isolates tested (95% CI: 0.918 to 0.977, p<0·001).We found that the pre-intervention slope for total antibiotic resistance was an IRR of 1.001 (CI: 0.999 to 1.003, p-value=0.346). The change in slope level for total antibiotic usage was an IRR of 0.999 (CI: 0.997 to 1.000, p=0.112). On examination of the long-term effect following implementation of the QP, there was an increase in the number of isolates resistant to at least one of the five broad-spectrum antibiotics tested.134Interpretation: Whilst interventions targeting antibiotic use can result in changes in resistance over a short period, they may be insufficient alone in curtailing antimicrobial resistance.