Meticillin-resistant Staphylococcus aureus in horses and horse personnel at the Finnish veterinary teaching hospital, 2006–2007

Abstract number: P1453

Rantala M., Thomson K., Myllyniemi A-L., Pitkälä A., Seppänen J., Kanerva M., Vuopio-Varkila J., Vainio A., Lyytikäinen O.

Objectives: We report the emergence of MRSA in horses at the Helsinki University Veterinary Teaching Hospital, in Finland during October 2006-June 2007.

Methods: After the first MRSA isolate in a horse was detected through routine wound infection surveillance in October 2006, active MRSA screening of horses at risk (hospitalised >24 h) was implemented. Swabs were obtained from nostrils, oral mucosa, perineum, and wounds. Voluntary screening of personnel (nostrils and skin lesions on hands) was performed on two occasions in 2006 and 2007. MRSA was confirmed by PCR of mecA and S. aureus specific nuc genes. MRSA isolates were characterised by pulsed-field gel electrophoresis (PFGE), spa typing, SCCmec and multilocus sequence typing (MLST). A case was defined as a horse or staff member with MRSA positive culture result. MRSA positive horses were handled with barrier nursing precautions in isolation or cohorts. The importance of hand hygiene and aseptic techniques in different procedures were emphasised.

Results: The first MRSA cluster with 2 wound infections and 3 colonisations among 98 horses (attack rate, AR 5%) occurred during October-December in 2006; all 24 screened personnel was negative. The 5 isolates were resistant to macrolides, fluoroquinolones and aminoglycosides, and identical in PFGE. MRSA strains were of ST125, spa type t1399, and SCCmec IVA. The second outbreak appeared in May 2007, and was also detected through wound infection surveillance. This cluster involved 3 infections and 10 colonisations among 61 horses (AR 21%). The index patient was a horse which was hospitalised during the first outbreak but was MRSA negative at that time. In staff screening, 1/25 person was colonised with MRSA. All 14 isolates were resistant to aminoglycosides and tetracyclines, but susceptible to fluoroquinolones and macrolides, were non-typeable by PFGE and possessed ST398, spa type t011, and SCCmec IV.

Conclusion: These are the first MRSA infections detected in horses in Finland. ST125 has been only seldom reported in humans in Finland, whilst ST398 is a new strain type in our country. Routine wound infection surveillance in the hospital was crucial in detecting MRSA. Early outbreak control measures, active screening of patients and staff training are necessary to prevent spread of MRSA in veterinary premises. Emerging MRSA infections in animals can cause a public health risk since strains causing infections in animals cause infections in humans and vice versa.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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