STORAGE OF MYCOPLASMA STRAINS.

Kelton, William H. (National Animal Disease Laboratory, Ames, Iowa). Storage of Mycoplasma strains. J. Bacteriol. 87:588-592. 1964.-Survival of Mycoplasma strains (19 of avian origin, 3 human, 3 canine, and 1 saprophyte) in the lyophilized state and at various storage temperatures was studied. The effect of alternate freezing and thawing was also studied. All strains survived the freeze-drying process and at least 3 or 4 years of storage in the lyophilized state. At -26 C, they survived for at least 10 months, but changes were noted in colony size and growth rate of cultures stored longer than 10 months. At -65 C, however, there was little loss in viable numbers from 12 months of storage, and no changes in the organisms were apparent. There was considerable variation from strain to strain in resistance to alternate freezing and thawing. Of 16 strains tested, 13 withstood the freezing and thawing better than did the bacterium Escherichia coli. At 5 C, again, there was considerable variation in survival between strains. The saprophytic strain, C-15, showed no apparent loss after 9 weeks at 5 C. Most other strains showed rather rapid loss of viable numbers when stored at 5 C.