猪源产细菌素肠球菌的分离鉴定

Isolation and Identification of Bacteriocin Producing Enterococcus from Swine

为了分离鉴定产细菌素类乳酸菌,采用双层琼脂扩散法,对从健康猪胃肠道分离到的56株细菌进行筛选,获得对大肠埃希菌及金黄色葡萄球菌均有抑制作用的12株细菌,在排除酸、过氧化氢等因素作用后仍具有较强抑菌活性,表明发酵液中还有其他抑菌活性物质的存在,用蛋白酶处理上清液后抑菌效价明显下降,表明这种抑菌物质具有蛋白质性质,能够被蛋白酶降解,初步确定为一种细菌素类物质。具有抑菌活性的菌株采用形态学和生理生化特征观察并结合16SrDNA序列分析、遗传进化树比较,结果显示,分离菌为革兰阳性,圆形或卵圆形的球菌,生理生化及糖发酵符合肠球菌属的特征;16SrDNA序列与GenBank中屎肠球菌FJ749740、粪肠球菌FJ749378同源性为99.3%～100%。综合判定E2、E3、E4、E5、E6、E7、E8、E10和E11 9株分离菌为粪肠球菌,E1、E9和E12 3株分离菌为屎肠球菌。细菌素作为潜在的抑菌物质,与其产生菌一起在平衡肠道菌群中具有重要意义。

To characterize lactic acid bacteria produced bacteriocin,the research isolated 56 strains Enterococcus from the digestive tracts of healthy swine.Using double-layer agar plate proliferation experiment（eliminating the effects of organic acid and H2O2,decreased after treatment with proteinase K,trypsin and papain） to screen 12 strains of bacteriocin producing E1-E12 which has antibacterial activity to Escherichia coli,Staphylococcus aureus.Through detection of its appearance,physiological and biochemical characteristics and 16 S rDNA gene sequence homology analysis,E2,E3,E4,E5,E6,E7,E8,E10 and E11 were identified as Enterococcus faecalis,E1,E9 and E12 as Enterococcus faecium.The bacteriocins are potential antimicrobial agents and,in conjunction with their producers,may be used to contribute a positive effect on the balance of intestinal microflora.