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Updated: Aug 18, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Methicillin-resistant Staphylococcus aureus isolated from dogs and cats in Switzerland
1Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Switzerland.
Introduction:
Twenty-two methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from various infected locations in domestic cats and dogs between June 2008 and September 2014 were analyzed for their genotype, genetic fingerprint, virulence and antibiotic resistance profile. Eighteen strains belonged to the clonal complex (CC) 22 [ST22(MLST)-A(PFGE)-t032(spa)-IV(SCCmec) and ST22-A-t1214-IV], 2 strains to the livestock associated MRSA ST398-t011-IV and two were individual strains of ST5-t002-II and ST1-t001-IV. They contained virulence factors such as γ-hemolysins, β-hemolysin converting phage genes, leukocidins and enterotoxins. Most widespread resistances were observed against β-lactams, trimethoprim and fluoroquinolones, but single strains also exhibited resistance to macrolides, lincosamides, aminoglycosides, tetracycline, chloramphenicol and/or mupirocin. The predominant presence of CC22 MRSA strongly indicates clonal spread of a human associated lineage in Swiss companion animals. It is therefore of public health importance to maintain a low level of MRSA infections in animals to avoid uncontrolled dissemination of MRSA clones in humans and animals.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) in pets is predominantly the CC22 clone, originating from humans. This highlights the public health importance of controlling MRSA in animals to prevent human transmission.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Resistance
- Public Health
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a One Health challenge, affecting both animals and humans.
- Understanding MRSA epidemiology in companion animals is crucial for public health surveillance.
- Previous studies have indicated the presence of MRSA in domestic animals, but clonal lineages require further investigation.
Purpose of the Study:
- To characterize methicillin-resistant Staphylococcus aureus (MRSA) strains from infected cats and dogs.
- To determine the genetic profiles, virulence factors, and antibiotic resistance patterns of these MRSA isolates.
- To investigate the clonal origins and potential for transmission between humans and companion animals.
Main Methods:
- Genotyping and genetic fingerprinting (MLST, PFGE, spa typing, SCCmec typing) of 22 MRSA strains.
- Analysis of virulence genes (hemolysins, leukocidins, enterotoxins).
- Antimicrobial susceptibility testing against a panel of antibiotics.
Main Results:
- Eighteen of 22 strains belonged to clonal complex (CC) 22, a lineage typically associated with human infections.
- Other identified strains included CC398 and individual strains of CC5 and CC1.
- Detected virulence factors included gamma-hemolysins, beta-hemolysin converting phage genes, leukocidins, and enterotoxins.
- Widespread resistance observed against beta-lactams, trimethoprim, and fluoroquinolones; some strains showed resistance to other antibiotic classes.
Conclusions:
- The predominance of CC22 MRSA in Swiss companion animals suggests clonal spread from human-associated lineages.
- This finding underscores the public health significance of MRSA in companion animals.
- Controlling MRSA infections in animals is essential to prevent the uncontrolled dissemination of resistant clones in both animal and human populations.
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