The effect of intervention by an antimicrobial stewardship team on anaerobic bacteremia

The effect of antimicrobial stewardship (AS) on anaerobic bacteremia is uncertain. This study aimed to assess the effect of interventions by the AS team (AST) on clinical and microbiological outcomes and antimicrobial use. An AS program was introduced at Osaka City University Hospital in January 2014; an interdisciplinary AST was established. We enrolled patients with anaerobic bacteremia between January 2009 and December 2018. Patients were classified into the pre-intervention group (from January 2009 to December 2013) and the post-intervention group (from January 2014 to December 2018). A significant decrease in definitive carbapenem use (P = 0.0242) and an increase in empiric tazobactam/piperacillin use (P = 0.0262) were observed in the post-intervention group. The de-escalation rate increased significantly from 9.38% to 32.7% (P = 0.0316) in the post-intervention group. The susceptibility of Bacteroides species and 30-day mortality did not worsen in the post-intervention group. These results showed that interventions by an AST can reduce carbapenem use and increase the de-escalation rate without worsening patient outcomes.