ENOVAT review questions routine antibiotics in companion animal surgery: full analysis

A new evidence review behind the ENOVAT surgical prophylaxis guidelines is challenging how much benefit companion animal practices can expect from routine perioperative antibiotics. In the Journal of Small Animal Practice, investigators reported that surgical antimicrobial prophylaxis had only a trivial to small clinical effect on surgical site infection risk in dogs and cats across the procedures studied, based on very low to moderate certainty evidence. (pubmed.ncbi.nlm.nih.gov)

The paper is part of a broader ENOVAT effort to build evidence-based antimicrobial guidance for companion animal medicine. That work has been in development for several years, including a 2024 scoping review that mapped the evidence landscape and identified major gaps in the literature. ENOVAT has also worked with WSAVA to support dissemination of these guidelines internationally, with an explicit stewardship goal: preserve antimicrobial effectiveness while still protecting patients when infection risk is meaningfully high. (pubmed.ncbi.nlm.nih.gov)

In the new review, the authors identified eight randomized trials and seven observational studies eligible for analysis. Procedures were divided into nine subgroups, including neutering, other clean soft tissue surgery, urologic and gastrointestinal surgery, contaminated procedures, orthopedic surgery with and without implants, and tibial plateau leveling osteotomy. Across those categories, the pooled evidence did not show a large protective effect from prophylaxis, and no adverse effects or mortality related to surgical site infections were reported in the included studies. The authors said the findings will be used to inform evidence-based treatment guidelines. (pubmed.ncbi.nlm.nih.gov)

That evidence now feeds directly into the ENOVAT 2025 guideline for surgical antimicrobial prophylaxis in dogs and cats. According to the guideline abstract, the panel issued strong and conditional recommendations for peri- and postoperative prophylaxis in soft tissue and orthopedic procedures, and specifically called on national and regional groups to use the document and supporting review to draft local guidance. Outside commentary from infectious disease specialist Dr. Scott Weese noted that the guidelines put “heavy emphasis” on when not to use antimicrobials, reflecting what the evidence currently supports, while still outlining circumstances where prophylaxis is appropriate and how to use it optimally. (pubmed.ncbi.nlm.nih.gov)

The broader direction is consistent with existing stewardship guidance. The 2022 AAFP/AAHA antimicrobial stewardship guidelines state that surgical antimicrobial prophylaxis is a very brief course started 30 to 60 minutes before first incision, is not usually needed for clean procedures, and rarely needs to continue postoperatively. Comparable Australian companion animal surgical guidance also recommends no prophylaxis for uncomplicated clean procedures, with short-duration use reserved for higher-risk scenarios such as implants, prolonged surgery, or major consequences if infection occurs. (aaha.org)

Why it matters: For veterinary professionals, this review adds weight to a practical shift already underway in many hospitals: moving from routine antibiotic coverage toward risk-based prophylaxis. That has implications for spay-neuter protocols, orthopedic implant cases, postoperative discharge medications, and quality improvement efforts tied to surgical site infection tracking. It also gives antimicrobial stewardship teams firmer footing when they ask surgeons to justify prophylaxis based on wound class, procedure type, patient comorbidities, implant use, expected duration, and the likely consequences of infection, rather than habit alone. (pubmed.ncbi.nlm.nih.gov)

At the same time, the review underscores how thin the veterinary evidence base still is. ENOVAT’s earlier scoping review and outside commentary both point to substantial knowledge gaps, and the systematic review itself drew on a relatively small number of studies with certainty ranging from very low to moderate. That means these recommendations are useful, but not the final word. Practices will still need clinical judgment, especially in referral settings, complex soft tissue cases, contaminated fields, and surgeries involving implants or medically fragile patients. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next phase is implementation. Expect local adaptations of the ENOVAT recommendations, more hospital-level auditing of perioperative prescribing, and likely pressure for better prospective studies that can clarify which patients truly benefit from prophylaxis, which drugs should be used, and when postoperative doses can safely be avoided. (pubmed.ncbi.nlm.nih.gov)