Promotion of antimicrobial stewardship following issuance of the antimicrobial resistance national action plan in Japan: A systematic review of 2016–2020

Background: Antimicrobial resistance (AMR) represents a global threat with the potential to cause a significant healthcare burden. In 2016, the Japanese Government issued the national action plan (NAP) for AMR. Since issuance of this plan, several studies on antimicrobial stewardship programmes (ASPs) have been published in Japan. This systematic review was undertaken to elucidate the current state of ASPs and the impact of the NAP. Methods: Medline (PubMed) and EMBASE were searched for studies published between January 2016 and the end of September 2021. The Risk of Bias in Non-Randomized Studies of Intervention tool was used to assess the risk of bias in interventional studies, and the Newcastle–Ottawa Scale was used to assess the quality of cohort, case–control and cross-sectional studies. Results: Eighty studies, including 30 (37.5%) interventional studies, 15 (18.8%) database-oriented studies and nine (11.3%) analytical studies (one case–control study, six cohort studies and two cross-sectional studies), were included. All of the interventional studies were before–after trials, and interrupted time series analysis was commonly used to assess changes in antimicrobial consumption per intervention. Five database-related studies demonstrated decreasing antimicrobial consumption after issuance of the NAP. Conclusion: Several ASP studies were published after issuance of the NAP, suggesting that the latter promoted research into ASPs. A few database-related studies showed a positive impact of the NAP on antimicrobial consumption. However, more high-quality studies, especially interventional studies using an appropriate methodology and standardized data collection, are needed.