Retrospective study of perioperative antimicrobial use in horses undergoing elective laparoscopy at a single institution

Antimicrobial stewardship has shown significant development in recent years. Perioperative prophylaxis accounts for a substantial volume of antimicrobial use and is a field in which improvements can likely be made. The objective of this study was to evaluate practices associated with perioperative antimicrobial use in equine elective laparoscopy at a single institution over a 21-year period and to determine whether antimicrobial therapy influenced the occurrence of postoperative complications. Medical records of horses that underwent elective laparoscopy at a teaching hospital from January 2000 to September 2021 were reviewed. Data obtained included signalment, surgeon, type and duration of procedure, perioperative antimicrobial use, and intraoperative and postoperative complications. Exact univariate logistic regression was used to explore the association between possible risk factors and occurrence of postoperative complications, as well as the association between year of presentation and time of antimicrobial administration. Duration of surgery was log- transformed to meet assumption of normality, followed by analysis of variance (ANOVA) to compare mean surgery time per procedure and postoperative complications. Significance was set at P, 0.05. Sixty horses met the inclusion criteria. All horses received antimicrobial prophylaxis, but none received intraoperative redosing. Only 13 horses (26%) received antimicrobials within 60 min of the first incision. Time of administration improved with each year of the study (P = 0.005). Only 17 horses (28%) received antimicrobials for less than 24 h, but median duration of antimicrobial therapy was 1.25 d (range: 0.25 to 10 d). Antimicrobial use practices at this institution differed from general recommendations for optimal perioperative prophylaxis, which suggests that intervention is required.