BACKGROUND: There are no reports on the effects of interventions, such as discontinuation and change/de-escalation of carbapenems and anti-methicillin-resistant Staphylococcus aureus (MRSA) antibiotics by an antimicrobial stewardship team focusing on detailed patient outcomes. This study aimed to evaluate these effects. METHODS: This retrospective cohort study was conducted at a tertiary care hospital from December 2018 to November 2019. RESULTS: Favorable clinical responses were obtained in 165/184 cases (89.7%) in the intervention-accepted group, higher than those in the not accepted group (14/19 cases, 73.7%; P=0.056). All-cause 30-day mortality was lower in the accepted group than in the not accepted group (1.1% and 10.5%, respectively; P=0.045). The microbiological outcomes were similar between the two groups. Duration of carbapenem and anti-MRSA antibiotic use in the accepted group was significantly lower than that in the not accepted group (median [interquartile range]: 8 days [5-13] versus 14 days [8-15], respectively, P=0.026 for carbapenem; 10 days [5.3-15] versus 15.5 days [13.8-45.3], respectively, P=0.014 for anti-MRSA antibiotic). CONCLUSION: This is the first study to investigate the effects of interventions such as discontinuation and change/de-escalation of antibiotics on detailed outcomes. Our intervention could reduce the duration of carbapenem and anti-MRSA antibiotic use without worsening clinical and microbiological outcomes.