Comparative Studies on the Stress Responses of vaginal Lactobacillus crispatus KLB46 and KLB79

초록

In previous studies, 108 vaginal Lactobacillus spp. were isolated from Korean women and L. crispatus KLB79 and L. crispatus KLB46 which showed high antimicrobial activity were selected. KLB79 maintained high viability for a long term (2 weeks) at low temperature (4°C). In this study, we conducted comparative studies on the response of two strains to stresses which can occur during the pharmaceutical formulation process. Tested stress conditions were acid (pH3.0), heat (60°C), NaCl (2M), dehydration (10g CaCl2), freeze-thaw stress, oxidative stress (0.01% H2O2), cold (4°C, 2 weeks), ethanol (10%), and freeze-drying. By following the growth curve of two strains after transferring to a fresh medium, the comparison of adaptation to a fresh medium and morphology after sub-culture was made. Following sub-culture KLB79 regained growth more rapidly than KLB46. When the cells were exposed to various stresses, KLB79 showed 10-104 fold higher viable cell number than KLB46: KLB79 maintained the higher viability in NaCl (2 M), at low temperature (4°C, 2 weeks) and under oxidative stress. To our surprise, unlike KLB46 when KLB79 was exposed in acidic MRS (pH 3.0) viability increased tenfold.