Antimicrobial resistance associations with national primary care antibiotic stewardship policy: Primary care-based, multilevel analytic study.

This evaluation of a national primary care stewardship policy on antimicrobial resistance in the community suggests both hoped-for benefits and unexpected harms. Some increase in resistance to cefalexin and co-amoxiclav could result from residual confounding. Randomised controlled trials are urgently required to investigate causality.