Comparison of the Long-Term Survival of Candida glabrata in Common Cryoprotectants Including; Glycerol, Glucose and Dimethyl Sulfoxide

Cryopreservation is one of the best long time preservation methods for fungi and using suitable cryoprotectants can increase the success of cryopreservation process. The aim of this study was to examine the effect of various cryoprotectants to protect of Candida glabrata in freezing conditions.
In this study, 50 clinical isolates of C. glabrata were stored at low temperature within three common cryoprotectants including; glycerol 10% and 40%, glucose 4% and DMSO 10%. After completing the preservation period, samples recovery rate was evaluated after two years using descriptive statistics and chi-square test.
In this study, 4% glucose with the ability to keep 100% of the samples, was determined as the best cryoprotectant for C. glabrata. Also, 40% glycerol and 10% DMSO with 94% success in retrieving samples, were comparable to each other and had a fairly good protective characteristic. While the 10% glycerol showed the lowest protective effect on C. glabrata. Recovery of samples cultured in SDA slant at 4ºC with a total of 32 (64%) positive cultures, showed a significant difference compared to preservation in freezing conditions. Also, the sample recovery in SDA had priority over SDB and yielded better results.
There was a significant difference between the cryoprotectants and by selecting a suitable cryoprotectant and appropriate concentration, survival of microorganisms can be increased in freezing conditions. Generally, assessment of a valid and reliable method for long-term preservation of a fungal strain should be associated with further studies on assessing changes in infectivity and pathogenicity, sporulation power and other features of microorganisms.