Antibiotic resistance has been recognized as a major global health threat and optimizing prescribing is one of the most effective measures to preserve the effectiveness of antibiotics. The quality of prescribing depends mostly on those prescribers belonging to clinical medical specialties having direct contact with patients. These doctors, who comprise the majority of antibiotic prescribers,undergo long-term undergraduate and postgraduate training that shapes their professional knowledge and behaviour J Antimicrob Chemother2019;74: 3611–3618doi:10.1093/jac/dkz375 Advance Access publication 3 September 2019