摘要
本文应用悉生小鼠做模型,研究了大肠杆菌(E.coli)和青春型双歧杆菌(Bifidobacterium adolescentis)对艰难梭菌(Clostridium diffi-cile)的拮抗作用。E.coli和B.adolescentis预先接种无菌SSB小鼠,再用C.difficile攻击。结果表明,E.coli和E.coli+B.adolescentis对小鼠均有保护作用,保护平分别为87.5%(7/8)和100%(8/8)。B.adolescentis定值后数量达10^(10.28)CFU/g,且对E.coli数量和小鼠本身无影响。E.coli和B.adolescentis联合比E.coli单独抑制C.difficile在肠道中繁殖的作用更强(0.02>P>0.01),但对其毒素产生和粘附力的作用无明显差异。C.difficile攻击后的1～14天,小鼠粪便中C.difficile菌数在10~4至10~8CFU/g内变化,细胞毒素为10~3CFU/g,A毒素滴度为10~2/g,B.adolescentis也一度下降10~2CFU/g。接种C.difficile后,小鼠虽无明显的腹泻症状,但组织学仍可观察到肠粘膜有充血和分泌增加等轻度损害。扫描电镜和普通光镜均发现E.coli单独或与B.adolescentis共同吸附在肠粘膜微绒毛表面,未见有C.difficile吸附。
The gnotobiotic mouse model was utilized to study the relationship between normal flora and Clostridium difficile.The germfree SSB mice were precedingly inoculated with E.coli and Bifidobacterium adolescen- tis,then challenged with C.difficile.It was found that both E.coli and E.coli+B.adolescentis manifested protection to mice against C.difficile,protectivity is 87.5%(7/8)and 100%(8/8)respecitivily. B.adolescentis coloized undamagedly in enteron of mice,the number reached 10^(10.28)CEU/g in faeces,and had no significient effect on number of E.coli.The union of E.coli and B.adolescentis was able to restrain much significantly the multiplication of C.difficile in mice than E.coli only,but toxin production and adherence of C.difficile had no difference between two groups.The number of C.difficile in faeces ranged from 10~4 to 10~8 CUFU/g,the average level of toxin in faecal extracts mainteined 10~3cu/g(cytotoxin)or 10~2/g(toxin A,RPHA titers) during 1 to 14 days of O.difficile challenged.No diarrhea happened in mice,but histologically,the slight lesion,such as hyperaemia,hyper- secretion existed in intestinal mucosa of two groups mice.It was obser- ved that the E.coli and B.adolescentis,but no C.difficile adheres to surface of microvilli of enteron by scanning electronic microscope or optical microscope
出处
《中国微生态学杂志》
CAS
CSCD
1992年第3期1-6,共6页
Chinese Journal of Microecology
关键词
大肠杆菌
艰难梭菌
双歧杆菌
小鼠
Escherichia coli
bifidobacterium adolescentis
clostridium difficile
gnotobiotic mice
