Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish
Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish
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DOI：
10.1111/j.1472-765x.2007.02258.x
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Sugita, H.
中科院分区：
文献类型：
--
作者：
Tsuchiya, C.;Sakata, T.;Sugita, H.
目的：为明确淡水鱼肠道中广泛分布的高产维生素B-12的A型拟杆菌的分类地位，从5种鱼类中分离到17株A型拟杆菌，均为革兰氏阴性杆菌。结果表明，该菌具有水解七叶苷、硝酸盐还原、抗胆汁酸、酸性磷酸酶活性，不产生过氧化氢酶和尿素酶，对万古霉素敏感。17株细菌DNA的G+C含量为29.1- 31.9mol%。16 SrDNA序列分析表明，A型拟杆菌与萨默塞特菌的同源性为99.7 ~ 100%。此外，菌株48 h内产维生素B-12的速率为1.82-13.98 ng/ml。结论：表型和系统发育特征表明，所有A型拟杆菌菌株均属于C.本研究的意义和影响：本研究为万古霉素耐药菌如C.淡水鱼肠道中的体部。
Aims: This study was conducted to clarify the taxonomic status of Bacteroides type A strains with high vitamin B-12-producing ability that is widely distributed in the intestinal tracts of freshwater fish.Methods and Results: Seventeen strains of Bacteroides type A isolated from five fish species were all rod-shaped and gram-negative. The strains were positive for esculin hydrolysis, nitrate reduction, resistance to bile, acid phosphatase, and negative for the production of catalase and urease and the susceptibility to vancomycin. The G+C content of DNA from the 17 strains was 29.1-31.9 mol%, and 16S rDNA sequence analysis revealed a close phylogenetic relationship between Bacteroides type A strains and Cetobacterium somerae sharing 99.7-100% sequence similarity. In addition, strains were capable of producing vitamin B-12 at a rate of 1.82-13.98 ng ml(-1) in 48 h.Conclusion: Phenotypic and phylogenetic characteristics indicated that all isolates previously classified as Bacteroides type A strains belong to C. someare.Significance and Impact of the Study: This study provided the important finding of novel niche of vancomycin-resistant bacteria such as C. somerae in the intestinal tract of freshwater fish.