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Updated: May 21, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
Factors associated with methicillin-resistant versus methicillin-susceptible Staphylococcus pseudintermedius
J Scott Weese1, Meredith C Faires, Linda A Frank
1Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada. jsweese@uoguelph.ca
Objective:
To compare methicillin-resistant Staphylococcus pseudintermedius (MRSP) and methicillin-susceptible S pseudintermedius (MSSP) infections in dogs.
Design:
Multicenter case-control study.
Animals:
Dogs with MRSP infections were matched, by hospital, with 2 MSSP controls, with the infections occurring immediately before and after the case infection.
Procedures:
Signalment, historical, clinical, treatment, and outcome data were documented. Conditional logistic regression was performed. A manual stepwise backward elimination procedure was used to build the multivariable model.
Results:
56 case and 112 control dogs were enrolled. Pyoderma was the most common infection type in both groups. In the final multivariable model, systemic administration of antimicrobials within 30 days prior to infection was significantly associated with an MRSP versus an MSSP infection (OR, 9.9; 95% confidence interval, 3.59 to 27.53).
Conclusions And Clinical Relevance:
The association of prior antimicrobial administration and MRSP infection indicated the potential impact of routine antimicrobial use in veterinary medicine on antimicrobial resistance and the need for prudent use of these important drugs. Mortality rate was not significantly different between MRSP and MSSP infections; the lack of a significant difference suggested that MRSP was inherently no more virulent than MSSP, provided the infection was properly diagnosed and appropriate treatment was started. Basic concepts such as prudent antimicrobial use and early diagnosis through timely submission of appropriate culture specimens therefore can be important measures to try to reduce the impact of this pathogen.
Insights
Prior antimicrobial use in dogs significantly increases the risk of methicillin-resistant Staphylococcus pseudintermedius (MRSP) infections compared to methicillin-susceptible S pseudintermedius (MSSP). MRSP and MSSP infections have similar mortality rates when diagnosed and treated promptly.
Area of Science:
- Veterinary Infectious Diseases
- Antimicrobial Resistance
- Canine Health
Background:
- Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an emerging pathogen in veterinary medicine.
- Understanding risk factors and outcomes associated with MRSP compared to methicillin-susceptible S pseudintermedius (MSSP) is crucial for effective treatment and control.
Purpose of the Study:
- To compare risk factors and outcomes of methicillin-resistant Staphylococcus pseudintermedius (MRSP) and methicillin-susceptible S pseudintermedius (MSSP) infections in dogs.
- To identify factors associated with MRSP versus MSSP infections in a canine population.
Main Methods:
- A multicenter case-control study design was employed.
- Dogs with MRSP infections were matched with two control dogs with MSSP infections.
- Signalment, historical, clinical, treatment, and outcome data were collected and analyzed using conditional logistic regression.
Main Results:
- Fifty-six dogs with MRSP and 112 control dogs with MSSP were enrolled.
- Pyoderma was the most common infection in both groups.
- Systemic antimicrobial administration within 30 days prior to infection was significantly associated with MRSP infection (OR, 9.9).
Conclusions:
- Prior antimicrobial administration is a significant risk factor for MRSP infections in dogs, highlighting the impact of routine antimicrobial use on resistance.
- Mortality rates did not differ significantly between MRSP and MSSP infections, suggesting similar virulence when diagnosed and treated appropriately.
- Prudent antimicrobial use and early diagnosis are essential to mitigate the impact of MRSP.
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