Selected cryopreservatives for long term storage of Helicobacter pylori at low temperatures.

To meet the need for information on cryopreservation, a study was done on 32 Helicobacter pylori strains, comparing different cryopreservative media. Sheep blood, horse blood, horse serum with and without glycerol, and mineral oil media were used for long term storage of H pylori at -70 degrees C or in liquid nitrogen. Procedures were developed which permitted recovery of 87.5% of the strains included in the study after they had been stored for 24 months. Of those strains stored for more than three years, 60% were recovered. It is concluded that most strains of H pylori can be stored for up to one year or longer, under refrigeration, at -70 degrees C or in liquid nitrogen.