Analysis of Probiotic Characteristics of Lactobacillus kefiri KL22

The article was based on Lactobacillus kefiri KL22 which was isolated from Polish Kefir. The rate of growth and acid producting were tested firstly. Then the certain probiotic properties of KL22 were evaluated,which contained hydrophobicity,self-aggregation,cholesterol lowering ability,immune effects of human intestinal cells Caco-2 and antibiotics sensitivity. The results showed that the hydrophobicity of KL22 was more than 80% against xylene,chloroform or ethyl acetate. Its self-aggregation was 21.17% after cultivate 5 h in room temperature. And after co-incubated with KL22 in 48 h,the degradation of cholesterol in culture medium was 52.94%. The real-time q-PCR showed that KL22 had a regulating effect on the expression levels of IL-8,TNF-α and BD-2. When the concentration of KL22 was 10⁸ CFU/mL,the expression levels of IL-8 and TNF-α were up-regulated,while the expression levels of BD-2 was down-regulated. When the concentration of KL22 was 10⁶ CFU/mL,the expression levels of IL-8、TNF-αand BD-2 were down-regulated. Finally,in aspect of antibiotic sensitivity,KL22 was moderately sensitive to tetracycline and was resistant to ciprofloxacin,vancomycin,compound sulfamethoxazole and oxacillin. In conclusion,KL22 was a potential strains which could be used as probiotic.