Utility of egg yolk medium for cultivation of Mycoplasma pneumoniae.

Chicken egg yolk broth medium containing 10% (vol/vol) phosphate-buffered saline extract of egg yolk instead of horse serum showed better growth-promoting activity for Mycoplasma pneumoniae than did Chanock medium and was effective in promoting the growth of small numbers of M. pneumoniae. Moreover, the phosphate-buffered saline extract of egg yolk proved superior to horse serum in the following respects: (i) it was consistent in growth-promoting activity for M. pneumoniae among different batches; (ii) it could be preserved at 4 degrees C for at least 2 years; (iii) it is inexpensive and easy to obtain; and (iv) it contains large amounts of lipoproteins, cholesterol, and phospholipids.