Retrospective multicentre study of methicillin-resistant Staphylococcus aureus infections in 115 horses.

This research article provides a detailed analysis of Methicillin-resistant Staphylococcus aureus (MRSA) infections in horses, focusing on the differences between community and hospital-associated infections and factors impacting survival rates.

Study Method and Sample

• The study retrospectively examined 115 horses from six different veterinary teaching hospitals in Canada and the United States, which were admitted between 2000 and 2006 and diagnosed with MRSA.
• The age range of the horses was from newborns (born in the hospital) to 31 years old.
• Multiple statistical analyses were conducted to understand the characteristics of the infections and the related survival rates.

Findings

• Around 51% of the MRSA infections were hospital-associated (HA) whilst roughly 49% were community-associated (CA)
• Surgical incision sites were the most common zones of infection, accounting for 38% of the total MRSA cases.
• Overall, around 84% of the horses survived until discharge.

Factors and Associations

• The study found prior hospitalisation and gentamicin treatment to be significantly associated with community-acquired MRSA.
• In contrast, infected incision sites had a significant association with hospital-acquired MRSA.
• Non-survival rates were significantly correlated with intravenous catheterisation, community-associated MRSA infection and the spreading of the infection to other parts of the horse’s body.

Conclusions

• The researchers concluded that equine MRSA infections have a wide range of clinical presentations and appear to be mostly opportunistic.
• The overall prognosis for survival to discharge was determined to be good.
• The findings of this research can be used to help understand risk factors for equine MRSA infection in both community and hospital populations, thereby directing future research in this area.