斜带石斑鱼肠道乳酸菌的分离、鉴定及特性分析

Isolation, Identification and Characteristics of Lactic Acid Bacteria from Intestine of Epinephelus coioides

从健康斜带石斑鱼肠道中分离出3株形态特征不同的菌株,经革兰氏染色、氧化酶及触酶反应筛选出3株革兰氏阳性球菌,通过生化鉴定和16S rRNA测序结果发现他们分别为粪肠球菌、乳酸片球菌和乳酸乳球菌,命名为WYZ-1、WYZ-2和WYZ-3。选取嗜水气单胞菌、溶藻弧菌、副溶血弧菌、哈氏弧菌以及大肠杆菌以琼脂扩散法测定WYZ-1、WYZ-2和WYZ-3的抑菌活性,结果表明WYZ-3对大肠杆菌无抑制作用,对溶藻弧菌、副溶血弧菌、哈氏弧菌和嗜水气单胞菌都有较显著的抑制作用,其中对溶藻弧菌和副溶血弧菌抑菌效果最好,抑菌直径为21.5~23.5 mm;粪肠球菌和乳酸片球菌均对5种致病菌有抑制作用,抑菌直径为9.5~22.5 mm。利用药敏纸片琼脂扩散法检测WYZ-1、WYZ-2和WYZ-3对34种常用抗生素的药敏性,结果表明3株乳酸菌均对氨基糖类、喹诺酮类多数、复方新诺明、多粘菌素B和氨曲南表现为耐药,对青霉素类多数、四环素类、大环内脂类及克林霉素和氯霉素敏感;WYZ-3对头孢类抗生素表现为敏感,WYZ-1和WYZ-2则对大部分头孢类抗生素表现为耐药。本研究表明三株乳酸菌均具有广谱抑菌性和对绝大多数抗生素有耐药性。

Three gram-positive strains were isolated by Gram stain,oxidase and catalase test from the intestines of the healthy Epinephelus coioides.The results of biochemical identification and 16S rRNA sequence showed the three strains were Enterococcus faecalis,Pediococcus acidilactici and Lactococcus lactis,named WYZ-1,WYZ-2 and WYZ-3 respectively.Aeromonas hydrophila,Vibrio alginolyticus,Vibrio parahaemolyticus,Vibrio harringensis and Escherichia coli were selected to measure the bacteriostatic activity of the three strains by agar diffusion method.The results showed WYZ-3 hadn't antibacterial effect on Escherichia coli,but had significant effect on Aeromonas hydrophila,Vibrio alginnolyficus,V.parahemolyticus and V.harveyi,with the antibacterial circle diameter was 21.5~23.5 mm on V.alginnolyficus and V.parahemolyticus.E.faecalis and P.acidilactici had good antibacterial spectrum on all of the tested pathogenic bacteria,and the antibacterial circle diameter was 9.5 to 22.5mm.To detect the sensitivity of WYZ-1,WYZ-2 and WYZ-3 to 34 common antibiotics by K-B method.The results showed that three strains of the lactic acid were sensitive to most of penicillin,tetracycline,macrolide,clindamycin and chloromycetin,and resistant to aminoglycoside,most of quinolones,bactrim,polymyxin B and aztreonam.WYZ-3 was sensitive to cephalosporin,but WYZ-1 and WYZ-2 were resistant to it.This study showed that three strains could inhibit the growth of wide-spectrum bacteria and they were resistant to most of antibiotics.