MRSA Risk for Horse Owners?

Hello Summarians!

We often think of risks to our patients and friends, but what about the risk to ourselves?

Sometimes, we are exposed to infectious disease and don’t even realize it. This study highlights one of those risks.

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Timed Up and Go (TUG) in Dogs

The study investigated the repeatability and validity of the canine Timed Up and Go (TUG) test—a clinical functional test originally developed for humans—to assess mobility in geriatric dogs. Researchers evaluated both within-session repeatability (using three TUG trials separated by one-minute rest periods) and short-term between-session repeatability (repeating the trials 20 days later) in a cohort of 24 stable geriatric dogs. Functional stability was ensured by employing validated canine client-specific outcome measures, and the results demonstrated strong reliability, particularly indicated by high intraclass correlation coefficients. This suggests that changes in TUG times of less than 2 seconds, especially in dogs with times under 10 seconds, may simply reflect normal variability rather than true changes in function. 

Additionally, the study explored the relationship between TUG times and accelerometry data, which objectively measures activity levels. It was found that TUG times correlated moderately with the amount of vigorous activity measured at home, indicating some overlap between the in-clinic test and at-home activity monitoring. The dogs in the study, although exhibiting a wide range of TUG times and some having confirmed mobility issues, maintained stable scores across various outcome measures, affirming that the cohort was functionally stable over the study period. Despite limitations such as a relatively small sample size and the specific population drawn from a university-affiliated setting, the findings support the TUG test as a reliable tool for assessing geriatric canine mobility. The study also highlights the need for further research to determine the effects of different levels of function, disease states, environmental factors, and procedural variations on TUG repeatability. 

Ellis, K. M., Rishniw, M., McMullin, K. M., Venator, K. R., Juran, I. G., Dudek, M., Miller, A. V., Lenfest, M. I., & Frye, C. W. (2025). Timed Up and Go demonstrates strong repeatability and correlates with vigorous activity as measured by accelerometry in geriatric dogs. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.25.02.0041 

Bottom line — Could be a useful tool for geriatric canine mobility

MRSA in Horses

This study investigated the prevalence and risk factors for nasal colonization by Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) in horses admitted to the Veterinary Teaching Hospital at the Université de Montréal. The researchers found that 17.5% of the horses were colonized by SA and 6.2% harbored MRSA, with the MRSA prevalence aligning with earlier reports from equine hospitals. Notably, previous hospitalization within six months emerged as a significant risk factor, suggesting that the hospital environment may act as a reservoir for MRSA, while horses housed in larger stables with increased contact opportunities also showed higher colonization rates. Although nasal carriage was common, the colonization appeared to be transient, as most MRSA-positive horses tested negative within 14 days after admission, and MRSA was not detected on the skin. All MRSA isolates displayed multidrug resistance, with some exhibiting extensive resistance, which raises concerns about treatment and infection control. The study acknowledges limitations such as a smaller sample size and potential recall bias in the questionnaire data, but it ultimately emphasizes the need for targeted preventive measures in veterinary hospitals to mitigate the risks of MRSA transmission to both horses and handlers. 

Allano, M., Arsenault, J., Archambault, M., Fairbrother, J.-H. and Sauvé, F. (2025), Prevalence and Risk Factors of Staphylococcus aureus Nasal Colonization in Horses Admitted to a Veterinary Teaching Hospital. J Vet Intern Med, 39: e70027. https://doi.org/10.1111/jvim.70027 

Bottom line — Targeted preventative measures needed to mitigate the risk of transfer.

Genetic Basis for Increased Oxygen Consumption in Horses

Researchers at Johns Hopkins University and Vanderbilt University have discovered an extraordinary instance of genetic recoding in horses, donkeys, and zebras where a mutation in the KEAP1 gene—normally expected to halt protein production due to a premature stop codon—actually results in the full-length, functional protein. Instead of stopping translation, the opal stop codon is recoded into a cysteine, a change enabled by unique alterations in both the KEAP1 mRNA structure and the proteins involved in translation. This adaptation enhances the sensitivity of the KEAP1 protein to electrophiles and reactive oxygen species, leading to increased NRF2 activity. As a result, there is an acceleration of mitochondrial oxygen consumption and ATP production coupled with a reduction in oxidative stress. The study, which involved comparative genetic analysis across equids, CRISPR-Cas9–mediated experiments, mass spectrometry, and metabolic assays, reveals that this molecular strategy—previously thought to be confined to viruses—has been co-opted during equine evolution. The mutation, present in all modern equine species, likely contributed to the exceptional aerobic performance of horses, whose muscle tissue can consume oxygen at rates far exceeding those of elite human athletes. Moreover, these findings may pave the way for novel biomedical approaches to counteract premature stop codon-associated disorders in humans. 

Gianni M. Castiglione et al. Running a genetic stop sign accelerates oxygen metabolism and energy production in horses. Science387,eadr8589(2025).DOI:10.1126/science.adr8589 

Bottom line — This explains their exceptional athletic performance.

Just putting things in perspective …