Multidrug-resistant bacterial pathogens associated with surgical site infections in veterinary medicine: an evidence-based systematic review

Background
Surgical site infections (SSIs) are among the most common postoperative complications in veterinary medicine and are increasingly driven by antimicrobial-resistant (AMR) pathogens. These infections result in prolonged hospitalization, treatment failure, increased healthcare costs, and represent a significant One Health concern due to the potential spread of resistant bacteria and resistance genes across animal, human, and environmental interfaces.
Objectives
This systematic literature review aimed to synthesize current evidence on the bacterial etiology of veterinary SSIs and to characterize antimicrobial resistance patterns among the isolated pathogens.
Methods
A comprehensive search was conducted in PubMed, Web of Science, Scopus, and CAB Abstracts from database inception to May 2025. Eligible studies reported culture-confirmed bacterial isolates from veterinary SSIs with antimicrobial susceptibility testing performed according to CLSI or EUCAST standards. Data on pathogen distribution, resistance profiles, multidrug resistance (MDR), animal species, and geographic origin were extracted. Thirty-two studies from Europe, North America, and Asia involving companion animals, equines, and livestock met the inclusion criteria.
Results
Staphylococcus spp., particularly S. pseudintermedius and S. aureus, were the predominant Gram-positive pathogens, while Escherichia coli, Pseudomonas aeruginosa, and Klebsiella spp. were most common among Gram-negative isolates. Gram-negative bacteria consistently showed higher resistance rates than Gram-positive organisms. Resistance to beta-lactam antibiotics ranged from 40% to 80%, tetracycline resistance from 30% to 70%, and the prevalence of multidrug-resistant isolates varied between 30% and 60%, demonstrating substantial heterogeneity across regions, species, and clinical settings.
Conclusions
Veterinary SSIs are frequently complicated by multidrug-resistant pathogens, posing major challenges to treatment and infection control. These findings underscore the urgent need for strengthened antimicrobial stewardship, standardized surveillance programs, and improved infection prevention and control measures in veterinary practice. Moreover, veterinary SSIs may serve as reservoirs for antimicrobial resistance with important implications for public health and food safety.