I need information for in vitro cultivation of Methicillin resistant S.aureus strain which is isolated from hospital waste. Moreover can someone suggest appropriate methods for identification of these strain?
The cefoxitin disk screen test is common. Other than that, the latex agglutination test for PBP2a, or a plate containing 6 μg/ml of oxacillin in Mueller-Hinton agar supplemented with 4% NaCl as alternative methods of testing for MRSA. After species determination all S. aureus isolates must be differentiated by susceptibility towards oxacillin. For confirmation of the antibiotic susceptibility phenotype, all S. aureus isolates should be then genotyped by PCR, which dtects the mecA gene that encodes the penicillin-binding protein-2, as it is considered to be the standard for identification of meticillin resistance in staphylococci.
Refer:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC262985/
http://www.cdc.gov/MRSA/lab/index.html
http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm071429.htm
YOu can use differential agar such as mannitol salts or Chromagar Staph aureus to enrich S. aureus. Pink colonies on Chromagar or yellow on MAnnitol salts are possible S aureus. Confirm with Catalase + and staphaurex +. Then you can do a mecA PCR and if you want to be fancy you can confirm the species with a Protein A gene PCR. You can confirm resistance using the tests described above.
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