SURVIVAL OF BACTERIA AFTER TWENTY-ONE YEARS IN THE DRIED STATE.

Miller, Ruth E. (Woman's Medical College of Pennsylvania, Philadelphia) and Loraine A. Simons. Survival of bacteria after twenty-one years in the dried state. J. Bacteriol. 84:1111-1114. 1962.-Cultures dried in a vacuum over calcium chloride at room temperature and stored in the refrigerator at 10 C were rehydrated after 21 years in this condition. Only 13 of 202 cultures, representing 67 different species, failed to grow. Nine of these were members of four different species, several other strains of which grew on rehydration. Failure to grow may have been due to a small inoculum before drying. Of 32 dried cultures removed from vacuum and stored in the refrigerator exposed to air, 9 survived for periods varying from 37 to 43 weeks. Cultures which survived generally retained the properties they had before drying. In this study, the grampositive organisms survived drying better than gram-negative bacteria. Since the number of organisms in the original inoculum before drying was not determined, quantitative studies could not be done. It is concluded that this procedure is a very satisfactory method for the preservation of even the most delicate organisms for long periods of time.