Question
To ask the Secretary of State for Environment, Food and Rural Affairs pursuant to the answer of 10 July 2007, Official Report, column 1381W, on livestock: MRSA, what testing has been carried out to detect MRSA in farm animals in the last 12 months; and what methodology was employed for the testing.
Answer
DEFRA has initiated a study undertaken by the Veterinary Laboratories Agency to test Staphylococcus aureus (S. aureus) isolates obtained from bovine clinical submissions for methicillin-resistant S. aureus (MRSA). This project commenced in autumn 2006.The methodology employed in the study involves determination of the minimum inhibitory concentration of oxacillin using the agar dilution method of the British Society for Antimicrobial Chemotherapy. All isolates are also examined using the disc diffusion method of the British Society for Antimicrobial Chemotherapy and a 10 microgram cefoxitin disc. Two different susceptibility testing methods are therefore used to check for the presence of methicillin resistance in the isolates.Additionally, all isolates are also examined using a molecular technique (polymerase chain reaction) for the presence of the mecA gene (the gene which confers resistance to methicillin in MRSA).Finally, a latex agglutination test is used to check for the altered penicillin binding protein of MRSA in any isolates which are not susceptible or which possess the mecA gene.The latest available figures are that 658 bovine S. aureus isolates from cases of clinical disease in cattle in England and Wales (mainly cases of mastitis for which milk samples are collected) have been tested and no MRSA isolates have been detected.