益生菌拮抗阪崎肠杆菌的初步研究

Preliminary study on the antagonism of probiotic strains against Enterobacter sakazakii

目的研究鼠李糖乳杆菌和植物乳杆菌等8种常见益生菌对阪崎肠杆菌的拮抗作用。方法采用牛津杯法测定益生菌耗尽上清对阪崎肠杆菌的抑菌圈,获得对阪崎肠杆菌具有较强抑菌能力的鼠李糖乳杆菌和植物乳杆菌;采用混合培养法对2株益生菌与阪崎肠杆菌的拮抗竞争能力进行测试。结果 8种益生菌耗尽上清均能抑制阪崎肠杆菌,其抑菌能力具有热稳定性且依赖于酸性pH环境。阪崎肠杆菌(107CFU/mL)与鼠李糖乳杆菌(108CFU/mL或109CFU/mL)共孵育至24 h,其活菌量开始逐渐下降,至120 h孵育结束下降到105CFU/mL;菌量比为1:10的阪崎肠杆菌与植物乳杆菌共孵育至24 h,其活菌量开始逐渐下降,菌量比为1:100时则提前至8 h,至120 h孵育结束活菌量均下降到102CFU/mL。结论鼠李糖乳杆菌和植物乳杆菌均能有效地竞争拮抗阪崎肠杆菌。

Objective To study the antagonism of eight common probiotic strains against Enterobacter sakazakii.Method The halo of the spent culture supernatant（SCS） of eight probiotic strains against Enterobacter sakazakii was determined by Oxford Cup Inhibition Method.It was found that L.rhamnosus and L.plantarum inhibited the growth of Enterobacter sakazakii significantly.To further verify the antagonism of the two probiotics strains,mixing cultivation method was approached.Result The SCSs of eight probiotic strains inhibited Enterobacter sakazakii significantly,and the antagonistic effects were dependent on low pH.The number of Enterobacter sakazakii（107 CFU/mL） began to decrease when incubated with L.rhamnosus（108 CFU/mL or 109 CFU/mL） for 24 h,and reached to 105 CFU/mL after 120 h.The initial inoculation ratio of probiotics against Enterobacter sakazakii affected the antagonistic effect.The cells of Enterobacter sakazakii began to decrease when incubated with L.plantarum for 24 h at the ratio of 1︰10,and for 8 h at the ratio of 1︰100,and finally reached to 102 CFU/mL.Conclusion Both L.rhamnosus and L.plantarum can effectively antagonise Enterobacter sakazakii.