鼠李糖乳杆菌PUM1749高盐和胆盐耐受能力与抑菌活性研究

Tolerances to high salt,bile salt and antibacterial activity of Lactobacillus rhamnosus PUM1749

目的以结肠癌术后患者粪便中分离出的鼠李糖乳杆菌PUM1749作为研究对象,通过检测其耐高盐、耐胆盐能力和抑菌活性,评价其益生特性。方法以鼠李糖乳杆菌GG为对照,将其和鼠李糖乳杆菌PUM1749分别培养于含不同浓度NaCl和胆盐的MRS肉汤中,采用滴种法进行活菌计数,采用双层琼脂夹心法结合滴种法检测两株菌对8种指示菌的抑菌效果。结果在不同浓度NaCl溶液培养24 h后,2株鼠李糖乳杆菌活菌数均在108 CFU/mL数量级以上。当浓度低于2 g/100 mL时,2株菌活菌数随NaCl浓度增加而减少,之后随着NaCl浓度的提高,PUM1749株活菌数均高于GG株;在不同浓度胆盐肉汤中培养4 h后,2株菌生长均被不同程度抑制,活菌数显著下降,PUM1749株在胆盐浓度为0.1 g/100 mL时生长被完全抑制,但继续提高胆盐浓度后,PUM1749株活菌数反而明显优于GG株;2株菌对8种指示菌均具有较好的抑菌效果,且对革兰阳性菌和革兰阴性菌的抑菌效果无明显差别。结论鼠李糖乳杆菌PUM1749在不同高盐和胆盐浓度条件下的耐受能力和抑菌活性均强于或持平鼠李糖乳杆菌GG。鼠李糖乳杆菌PUM1749具有良好的益生特性。

Objective Lactobacillus rhamnsus PUM1749,a strain isolated from the feces of patients after colon cancer surgery,was used as the subject to evaluate its probiotic properties by testing its tolerance to high salt and bile salt and antibacterial activity.Methods Using L.rhamnosus GG as a control,the two strains were cultured in MRS broth containing different concentrations of NaCl and bile salt,and the viable bacteria was counted with dot inoculation method.The bacteriostatic effects of the two strains on 8 indicator bacteria were detected using double-layer agar sandwich method combined with dot inoculation method.Results After 24 hours of culture with different concentrations of NaCl solution,the viable counts of the two strains maintained above 108 CFU/mL.When the concentration was lower than 2 g/100 mL,the viable counts of the two strains decreased with the increase of NaCl concentration,and then with the increase of NaCl concentration,the viable count of L.rhamnosus PUM1749 was higher than that of LGG.After being cultured in bile salt solution with different concentrations for 4 h,the growth of both strains was inhibited to varying degrees,and the viable bacterial counts decreased significantly.The growth of L.rhamnosus PUM1749 was completely inhibited when the bile salt concentration reached 0.1 g/100 mL,but its viable bacteria count was significantly more than that of LGG after increasing bile salt concentration.The two strains presented good bacteriostatic effects on 8 indicator bacteria,and there was no significant difference in bacteriostatic effect between Gram-positive bacteria and Gram-negative bacteria.Conclusion L.rhamnosus PUM1749 is stronger than or compouable to L.rhamnosus GG in terms of tolerance and inhibitory activity at different high salt and bile salt concentrations.L.rhamnosus PUM1749 has good probiotic properties.