ObjectiveTo investigate the effects of antimicrobial management program on inpatients outcomes and antimicrobial resistance among clinical isolates in a large-scaled university hospital.MethodsThe antibiotics use density (AUD) and antimicrobial resistance rate of multi-drug resistant bacteria before (from January 2009 to December 2010) and after (from January 2012 to December 2016) the intervention of antimicrobial management program in a large-scaled university hospital (4 300 beds) were calculated and compared, and the correlations of AUD with average length of hospital stay and mortality rate were analyzed.ResultsThe AUD was significantly decreased after intervention (P<0.001). The resistance rate of Staphylococcus aureus to oxacillin decreased (P<0.001). Among Gram-negative bacteria, the resistance rates to carbapenems in Acinetobacter baumannii (P<0.001) and Klebsiella pneumoniae increased (P=0.011). AUD was not correlated with the average length of hospital stay (P=0.644), while positively correlated with the in-hospital mortality rate (r=0.932, P=0.001).ConclusionsThe implementation of antimicrobial management program can significantly reduce the antimicrobial use and do not worsen patient outcomes in the hospital. The impact of the program on resistance varies significantly depending on both the bacterium and the agent, and carbapenem-non-susceptible Gram-negative bacilli emerges as a major threat. It is still necessary to combine other infection control measures.