Does anyone know of a media that inhibits the growth of organisms other than Gram +ve cocci? (or if not most of them) I know of Baird Parker media but have read that this has more specificity for Staphylococcus Aureus than others.
Also any tests used to distinguish Gram +ve cocci from each other would be helpful, I have been using coagulase activity to distinguish Staphylococcus Aureus from others. As yet though cannot find a test that will distinguish Staphylococcus Epidermis from other species.
You can use CNA medium. It is a selective medium for gram + cocci
see also this link: http://www.biotec.com/FullDetails.asp?product_id=219
You can use katalase to distinguish Staphylococcus species from other gram + species.
So when you combine the coagualase test with the katalase test you can tell if you have determined a Staphylococcus aureus, a coagulase negative Staphylococcus or other gram + species such as Streptococcus.
If you want to know if you are dealing with a Staphylococcus epidermidis you need to do some biochemical tests. You have special systems for that. A simple one is the API system. But most of the time it is enough to tell you are dealing with a Staphylococcus aureus, CNS or non Staphylococcus.