Background:Sepsis was the leading cause of inpatient mortality from intensive care unit admission in Malaysia. It was worsened by emerging multiple drug resistant bacteria, like ESBL-producing Enterobacteriaceae. In response to antimicrobial resistance, Antimicrobial Stewardship Program (ASP) was developed. One of the activities is antibiotic de-escalation which prefers narrower spectrum antibiotics as definitive therapy. This study aimed to evaluate the clinical outcomes and treatment costs among patients treated with group 1 carbapenem (ertapenem) and group 2 carbapenem (meropenem or imipenem) for sepsis caused by ESBL-producing Enterobacteriaceae.Methodology:A retrospective cross-sectional study was conducted in a tertiary care hospital to evaluate clinical outcomes [all-cause inpatient mortality, readmission within 30 days after discharge, and length of stay (LOS)] as well as treatment costs among patients with carbapenem therapies for sepsis caused by ESBL-producing Enterobacteriaceae. Observational data was collected from January to December 2017. Results:Patients treated with group 1 had significantly lower mortality rate (0/16 versus 11/31, p<0.05) and shorter hospital LOS (14 versus 44 days, p<0.05) than patients treated with group 2. Despite of significantly lower consumption of group 1 (9.31 versus 18.68 DDD, p<0.05), there were no statistical difference of durations of carbapenem therapy (10 versus 14 days, p>0.05) and treatment costs (RM1020.74 vs RM803.49, p>0.05) between group 1 and group 2. Conclusion:The use of narrow-spectrum carbapenem was adequately associated with lower mortality rate and shorter hospital LOS. However, the difference between ertapenem and meropenem/imipenem were without association to duration of therapy and treatment costs.