Impact of antimicrobial stewardship implementation on the antibiotic use and susceptibility in a Japanese long-term care hospital

Background: Antimicrobial use (AMU) is closely related to the emergence of antimicrobial -resistant (AMR) bacteria. Meanwhile, long-term care hospitals (LTCHs) have been pointed out to be important reservoirs for AMR. However, evidence illustrating the association between AMU and AMR in LTCHs is lacking compared to that of acute care hospitals. Methods: We evaluated the impact of an antimicrobial stewardship (AS) program implementation, in a LTCH on AMU and antibiotic susceptibility between three periods: the pre -AS -period (pre -AS); the first period after AS implementation (post -AS 1), in which initiated recommendation the blood culture collection and definitive therapy by AS team; and the second period (post -AS 2), implementation of a balanced use of antibiotics was added. Results: After the AS implementation, a significant increase in the number of blood cultures collected was observed. Conversely, the AMU of piperacillin-tazobactam (PIPC/TAZ), which has activity against Pseudomonas aeruginosa, was increased and occupied 43.0% of all injectable AMU in post -AS 1 compared with that in pre -AS (35.5%). In the post -AS 2 period, we analyzed the %AUD and recommended hospital -wide PIPC/TAZ sparing; this resulted in the significant reduction in %AUD of PIPC/TAZ, which was associated with improved susceptibility of P. aeruginosa to PIPC/TAZ. Conclusions: These results suggest that AS programs aimed at implementing antibiotic sparing may lead to improve AMR, highlighting the necessity of correcting overuse of a single class of antibiotics and usefulness of AMU monitoring in the LTCH setting.