Authors: Bustos Carla P, Dominguez Johana E, Garda Daniela, Moroni Mirian, Pallarols Molinari Natalia, Herrera Mariana, Chacana Pablo A, Mesplet María
Journal: Journal of equine veterinary science
Summary
# Editorial Summary During 2017, an outbreak of *Salmonella* ser. Typhimurium diarrhoea affected three hospitalised horses in Argentina, prompting investigation into the clonal relationships and antimicrobial resistance profiles of the causative isolates. Using pulsed-field gel electrophoresis and susceptibility testing, researchers identified that all three equine isolates shared an identical pulsotype that had previously been documented in human and porcine cases, indicating cross-species transmission of the same strain. Notably, the isolates demonstrated multidrug resistance with variable β-lactam susceptibility, and the *blaCTX-M-14* gene—conferring extended-spectrum cephalosporin resistance—was detected in an equine-origin *Salmonella* isolate for the first time in Argentina. These findings underscore the zoonotic significance of nosocomial *Salmonella* infection and highlight that empiric antimicrobial therapy for equine salmonellosis may be ineffective without understanding local resistance patterns; practitioners should therefore advocate for routine susceptibility profiling of clinical isolates at their facilities to guide rational treatment selection and support infection control protocols in hospital settings.
Read the full abstract on PubMed
Practical Takeaways
- •Salmonella ser. Typhimurium in hospitalized horses may represent zoonotic strains circulating across multiple species; implement strict biosecurity and hygiene protocols to prevent human and other animal exposure
- •Multidrug-resistant Salmonella with extended-spectrum β-lactamase production is emerging in equine practice; routine local antimicrobial susceptibility testing is essential to guide empiric treatment decisions rather than relying on standard protocols
- •Consider Salmonella as a differential diagnosis in hospitalized horses with diarrhea and implement appropriate infection control measures, especially given the public health implications of resistant strains
Key Findings
- •Three horses with diarrhea in an Argentinian equine hospital yielded Salmonella ser. Typhimurium isolates with identical pulsotypes
- •The same pulsotype had previously been detected in human and porcine isolates, indicating cross-species strain circulation
- •Multidrug-resistant isolates were identified with blaCTX-M-14 detected for the first time in an equine-origin isolate in Argentina
- •Isolates displayed varying β-lactam susceptibility profiles despite multidrug resistance phenotype