Evidence and Molecular Characterization of Multidrug Resistant Staphylococcus aureus Isolated From Equines in Pakistan.
Authors: Anwaar Farwa, Ijaz Muhammad, Rasheed Hamza, Shah Syed Faizan Ali, Haider Syed Ali Raza, Sabir Muhammad Jawad
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Researchers in Pakistan screened 203 equines (horses, donkeys, and mules) for nasal carriage of *Staphylococcus aureus* and characterised their antibiotic resistance profiles using both phenotypic and molecular methods, including PCR detection of *mecA* and *vanB* genes alongside phylogenetic analysis. Overall prevalence of *S. aureus* colonisation was 42.86%, with 14.94% of isolates harbouring methicillin resistance and 13.79% carrying vancomycin resistance genes, representing a concerning burden of multidrug-resistant organisms in the equine population studied. Management factors emerged as critical risk indicators: work intensity, stocking density, presence of other livestock on-site, and shared water sources all significantly influenced colonisation rates, suggesting that housing and husbandry practices—rather than species type alone—drive resistance emergence. Antimicrobial susceptibility testing revealed widespread cross-resistance to multiple commonly prescribed antibiotics within both MRSA and VRSA isolates, limiting therapeutic options for respiratory and wound infections in affected animals. These findings underscore the need for judicious antibiotic stewardship in equine practice, enhanced biosecurity protocols around mixed-species grazing and watering systems, and consideration of management intensification as a potential driver of resistance development in equine populations.
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Practical Takeaways
- •Multidrug-resistant S. aureus is prevalent in Pakistani equine populations; practitioners should be aware of resistance patterns when selecting antimicrobials for treatment
- •Management factors including high stocking density, shared water sources, and work intensity increase colonization risk—review biosecurity and husbandry practices
- •Nasal colonization is common (42.86%); consider screening protocols and infection control measures, particularly in facilities with multiple animals in close contact
Key Findings
- •Overall prevalence of S. aureus in equines was 42.86% based on nuc gene detection
- •14.94% of isolates were methicillin-resistant (MRSA) and 13.79% were vancomycin-resistant (VRSA)
- •26.44% of isolates showed phenotypic vancomycin resistance by disc diffusion testing
- •Significant risk factors included raising purpose, work intensity, stocking density, presence of other livestock, and common drinking water sources