eaton's agar eaton's agar eaton's agar is a type of agar media is used to grow mycoplasma pneumoniae. one recipe for the cultivation of m. pneumoniae (eaton's agar) includes (v/v): 70% difco pplo (pleuropneumonia-like organism) agar or broth base 20% unheated horse serum 10% fresh aqueous extract of baker's yeast 1000 units/ml penicillin g