Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Acinetobacter baumannii among horses entering a veterinary teaching hospital: The contemporary "Trojan Horse".
Authors: Walther Birgit, Klein Katja-Sophia, Barton Ann-Kristin, Semmler Torsten, Huber Charlotte, Wolf Silver Anthony, Tedin Karsten, Merle Roswitha, Mitrach Franziska, Guenther Sebastian, Lübke-Becker Antina, Gehlen Heidrun
Journal: PloS one
Summary
# Editorial Summary: ESBL-Producing Bacteria in Hospital-Admitted Horses Multidrug-resistant Gram-negative pathogens represent an emerging biosecurity concern in equine veterinary practice, yet their prevalence in clinical populations remains poorly characterised. Researchers screened 341 horses admitted to a German veterinary teaching hospital—233 with colic and 108 with open wounds—taking faecal, nasal and wound swabs to establish colonisation rates of extended-spectrum beta-lactamase (ESBL)-producing bacteria and other resistant pathogens. Alarmingly, faecal carriage of ESBL-producing *Escherichia coli* was identified in 10.7% of samples, with no meaningful difference between disease groups (10.5% colic, 11% wounds), whilst nasal colonisation was lower at 2.6% overall; importantly, 92.7% of isolated ESBL-producing *E. coli* exhibited resistance to three or more antimicrobial classes, predominantly harbouring the *blaCTX-M-1* gene (75.6%). Genetic analysis revealed considerable strain diversity but with concerning clonal clustering around sequence types 10 and 1250, suggesting both endemic circulation and multiple introduction events rather than hospital-acquired spread. These findings demand heightened infection control protocols in equine hospitals—including admission screening, isolation facilities and judicious antimicrobial use—to mitigate occupational exposure risks to veterinary staff and prevent cross-contamination of the broader equine population.
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Practical Takeaways
- •Approximately 1 in 10 horses admitted to teaching hospitals carry multi-drug resistant E. coli in faeces, requiring strict isolation protocols and enhanced biosecurity measures to protect other patients and staff
- •Standard antibiotic choices may be ineffective for infections in horses carrying these resistant strains; culture and sensitivity testing should guide treatment decisions for clinical infections
- •Veterinary staff should implement enhanced personal protective equipment and hygiene procedures when handling horses with colic or open wounds, as respiratory and wound carriage rates remain clinically significant
Key Findings
- •10.7% of faecal specimens were positive for ESBL-producing Enterobacteriaceae, with 94% being ESBL-producing E. coli
- •92.7% of ESBL-producing E. coli isolated showed phenotypic resistance to three or more antimicrobial classes
- •Nostril swab detection rates for ESBL-E were 3.4% in colic patients and 0.9% in open wound patients (average 2.6%)
- •Predominant sequence types were STC10 and STC1250, with blaCTX-M-1 (75.6%) and blaSHV-12 (24.4%) being the most common ESBL-associated genes