Abstract
Background:
Traumatic wounds are a common condition in horses, posing significant challenges to both animal welfare and the equine industry’s economic sustainability. Subcutaneous tissue exposure creates a favourable environment for bacterial colonisation and proliferation, which complicates wound management and delays healing. This clinical challenge is often exacerbated by empirical antimicrobial use, which drives the emergence of antimicrobial-resistant (AMR) organisms.

Aim:
This study aimed to identify bacterial species associated with traumatic wounds in horses in Peninsular Malaysia and to determine their antimicrobial susceptibility profiles.

Methods:
A cross-sectional study was conducted from February to August 2024 involving 58 horses with traumatic wounds sampled across seven Malaysian states. Wound swabs were collected using the Levine technique and cultured on blood and MacConkey agar. Bacterial isolates were identified using phenotypic and biochemical characterisation. Antimicrobial susceptibility testing of predominant isolates from chronic wounds was performed using the Kirby–Bauer disk diffusion method.

Results:
A total of 205 bacterial isolates were recovered, comprising 56.6% Gram-positive and 43.4% Gram-negative species. Chronic wounds (56.1%) yielded more isolates than acute wounds (43.9%). The most frequently isolated bacteria were Staphylococcus aureus (24.9%), Escherichia coli (15.6%), Streptococcus sp. (7.8%), Corynebacterium sp. (6.8%), and Klebsiella pneumoniae (6.3%). Penicillin resistance was identified in S. aureus (92.3%) and Corynebacterium sp. (71.4%). In contrast, 100% susceptibility to imipenem was preserved across all tested species. Notably, 23.0% of the tested isolates were classified as multidrug-resistant (MDR).

Conclusion:
These findings reveal the polymicrobial nature of traumatic wounds in the sampled horses in Malaysia, with S. aureus and E. coli as predominant pathogens. The detection of MDR isolates emphasises the need for culture-based diagnosis and prudent antibiotic use. This study provides essential insights to guide veterinarians and horse owners in improving wound management and promoting equine health and welfare.

Key words: Antimicrobial susceptibility; Bacterial colonisation; Chronic wound infection; Equine wounds; Multidrug resistance.