Antimicrobial Resistance and Extended-Spectrum Beta-Lactamase (ESBL) Genes in E. coli Isolated from Equine Fecal Samples in Turkey.
Authors: Yiğin Akın
Journal: Journal of equine veterinary science
Summary
# Editorial Summary The indiscriminate use of antimicrobials in veterinary and human medicine—particularly in developing countries where regulation is less stringent—has driven the emergence of multidrug-resistant (MDR) bacterial strains that now pose a significant threat to equine health. Akın investigated the prevalence of extended-spectrum beta-lactamase (ESBL)-producing *Escherichia coli* on Turkish horse farms by screening 200 faecal samples from 140 horses across 16 farms using real-time PCR to detect five key resistance genes (blaCTX-M, blaTEM, blaSHV, blaOXA-48, and blaKPC). Over half the isolates (53.5%) carried at least one ESBL gene, with blaCTX-M being the most common; critically, many strains harboured multiple resistance genes simultaneously, including three isolates carrying all five tested genes—indicating highly resistant pathogens that would be refractory to conventional beta-lactam therapy. For equine practitioners, these findings underscore the urgent need for judicious antibiotic prescribing protocols and routine surveillance of *E. coli* on breeding and racing operations, as ESBL-producing strains can compromise treatment options for colitis, sepsis, and other common infections in this population. Given that faecal carriage precedes clinical disease and cross-contamination is inevitable in shared facilities, implementing rigorous biosecurity measures and antimicrobial stewardship programmes should be prioritised to slow the trajectory of resistance on individual yards.
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Practical Takeaways
- •Over half of E. coli isolates from Turkish horse farms produce ESBLs, making standard beta-lactam antibiotics unreliable for treatment of bacterial infections on these farms
- •The high prevalence of multidrug-resistant strains with multiple resistance genes suggests routine susceptibility testing should be performed before prescribing antibiotics for equine infections
- •Veterinarians should implement strict antibiotic stewardship protocols and consider alternative treatment options, as many common antibiotics may be ineffective against these resistant E. coli strains
Key Findings
- •53.5% (107/200) of E. coli strains isolated from equine fecal samples carried at least one ESBL gene
- •blaCTX-M was the most frequently detected single gene (11 strains), followed by blaSHV (6 strains) and blaTEM (4 strains)
- •Multiple ESBL gene coexistence was common, with 16 strains carrying blaCTX-M+blaSHV and 7 strains carrying all four genes (blaCTX-M, blaTEM, blaSHV, blaoxa-48)
- •ESBL-producing E. coli strains were frequently detected in racehorses from eastern Turkey, indicating widespread antimicrobial resistance likely driven by antibiotic misuse