Cell-assisted growth of a fastidious spiroplasma.

The Colorado potato beetle spiroplasma, which is not cultivable in conventional cell-free media, grew in tissue culture media in the presence of several coleopteran and lepidopteran insect cell lines. The cultured organisms attained titers of 1.2 x 10(9) spiroplasmas per milliliter of culture at the 100th passage and retained infectivity and a high capacity for translational motility at the 15th passage. Cell culture systems may facilitate the isolation of other presently uncultivable microorganisms and may be useful in the study of the role of microbial physiology and behavior in pathogenicity.