<![CDATA[Escherichia coli is a normal commensal bacterium in the gastrointestinal tract of animals; however, some strains may become pathogenic and develop antimicrobial resistance. This study aimed to identify E. coli from the feces of Cidomo horses at Kebon Roek Market, Ampenan, and to determine their antibiotic resistance profile, including the presence of multidrug-resistant (MDR) isolates. A total of 36 fresh fecal samples were collected purposively and cultured on Eosin Methylene Blue Agar (EMBA), followed by Gram staining and biochemical tests for confirmation. Antimicrobial susceptibility was assessed using the disk diffusion method against streptomycin, aztreonam, tetracycline, ciprofloxacin, and trimethoprim–sulfamethoxazole, and interpreted according to CLSI (2020) guidelines. MDR isolates were further tested using the Double Disk Synergy Test (DDST) to detect Extended Spectrum Beta-Lactamase (ESBL) production. The results showed that 7 of 36 samples (19.44%) were confirmed as E. coli. High resistance levels were observed against streptomycin and aztreonam, whereas tetracycline and ciprofloxacin exhibited the highest effectiveness. Three isolates (42.85%) were classified as MDR, displaying resistance to ≥3 antibiotic classes. All MDR isolates tested negative for ESBL production using DDST. These findings indicate that Cidomo horses may act as reservoirs of antibiotic-resistant E. coli in market environments. Strengthening hygiene management and promoting prudent antimicrobial use in animals are essential to reduce the risk of antimicrobial resistance transmission within the One Health framework.]]>
