Characterisation of methicillin-resistant Staphylococcus aureus clinical isolates from animals in New Zealand, 2012–2013, and subclinical colonisation in dogs and cats in Auckland. Issue 2 (4th March 2017)

• Record Type: Journal Article
• Authors: Karkaba, A; Benschop, J; Hill, KE; Grinberg, A
• Is Part Of: New Zealand veterinary journal. Volume 65:Issue 2(2017)
• Page Start: 78
• Page End: 83
• Publication Date: 2017-03-04
• Subjects: Antimicrobial resistance -- Antibiotic -- MRSA -- Staphylococcus aureus -- New Zealand; Veterinary medicine -- Periodicals; Médecine vétérinaire -- Périodiques; 636.089
• DOI: 10.1080/00480169.2016.1222919
• Languages: English
• ISSNs: 0048-0169

Abstract

Abstract: AIMS: To characterise methicillin-resistant Staphylococcus aureus (MRSA) isolates from infection sites in animals in New Zealand and assess the prevalence of subclinical MRSA colonisation in dogs and cats attending veterinary clinics in Auckland. METHODS: MRSA isolates from clinical specimens obtained by the main New Zealand veterinary diagnostic laboratories between June 2012 and June 2013, were genotypically characterised by DNA microarray hybridisation analysis and spa typing. In addition, nasal or perineal skin swabs collected from a cross-sectional sample of dogs (n=361) and cats (n=225) attending 29 veterinary clinics in Auckland during the same period were analysed for MRSA by culture. RESULTS: Eight MRSA clinical isolates were submitted for characterisation by the participating laboratories. The isolates originated from five dogs, including two isolates from the same dog, one foal, and one isolate had no identification of the source. The strain-types identified were AK3 (ST-5 SCC mec IV t045; n=1), USA500 (ST8 SCC mec IV t064; n=1), WSPP (ST30 SCC mec IV t019; n=1), Rhine Hesse (ST5 SCC mec II t002; n=2), and EMRSA-15 (ST22 SCC mec IV t032; n=3). No MRSA were isolated from 586 cultured swabs. Methicillin-susceptible S. aureus were detected in 9/257 (3.5%) swabs and non- aureus staphylococci in 22/257 (8.5%) swabs. The estimated true MRSA subclinical colonisation prevalence was 0%, with an upper 95% CI boundary of 1.9% for cats and 1.4% for dogs. CONCLUSIONS: The modest number of MRSA isolates submitted for this study by the participating laboratories suggests clinical MRSA infection in animals in New Zealand continues to be sporadic. The wide variety of strain-types found mirrored the evolving strain-type diversity observed in humans. We cannot rule out bias due to the non-random sampling of dogs and cats, but the apparent colonisation prevalence of 0% was consistent with the low prevalence of subclinical colonisation in humans in New Zealand. These similarities indicate the epidemiology of animal and human MRSA infections are linked. CLINICAL RELEVANCE: In the last decade, the prevalence of human MRSA infections in New Zealand has steadily increased. This is the second published study of MRSA in animals in New Zealand. The results indicate clinical MRSA infection in animals remains sporadic, but the diversification of the strain-types may pose new therapeutic challenges to veterinarians, due to their diverse resistome.