Quality-Control Testing of Mycoplasma Medium

Mycoplasmas lack many of the biosynthetic pathways of higher organisms; consequently, their growth and survival depend on an external supply of a wide variety of nutrients. Because they are very fastidious in their nutritional requirements, a complex growth medium is required for their culture. Although the exact requirements of most mycoplasma species are still incompletely defined, most can be grown in the laboratory in both liquid and solid agar media formulated to comprise as a minimum: a broth base, yeast extract, serum source, and solutions of pure chemicals. Details of components added to any particular medium will vary, according to the species of mycoplasma it is intended to culture (see Chapters 4 –6 ). It is clear that such a large number of components must inevitably introduce a degree of variability to the growth-promoting properties of the mycoplasma media between formulation lots. Consequently, it is of paramount importance that the introduction of any new component into a formulation and the preparation of media lots should always be accompanied by a quality validation with mycoplasma strains that the particular formulation is intended to support. This quality-control (QC) testing should cover all components, including preparations of pure chemicals (e.g., glucose and arginine) because although intrinsically these chemicals are unlikely to vary between lots supplied by the same manufacturer in the same way that broth base, serum, and yeast extract might, it is still necessary to exclude the possibility that errors may have occurred during their preparation (see Note 1 ).