Murugkar Pallavi P, Collins Andrew J, Chen Tsute, Dewhirst Floyd E
Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.
Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA.
J Oral Microbiol. 2020 Sep 6;12(1):1814666. doi: 10.1080/20002297.2020.1814666.
The vast majority of bacteria on earth have not yet been cultivated. There are many bacterial phyla with no cultivated examples including most members of the Candidate Phylum Radiation with the exception of human oral isolates from the phylum Saccharibacteria.
The aims of this research were to develop reproducible methods and validate approaches for the cultivation of human oral Saccharibacteria and to identify the conceptual pitfalls that delayed isolation of these bacteria for 20 years after their discovery.
Oral samples were dispersed and passed through 0.2 µm membrane filters. The ultrasmall saccharibacterial cells in the filtrate were pelleted, inoculated into broth cultures of potential bacterial host cells and passaged into fresh medium every 2-3 days.
Thirty-two isolates representing four species of Saccharibacteria were isolated in stable coculture with three species of host bacteria from the phylum . Complete genome sequences were obtained for 16 isolates.
Human oral Saccharibacteria are obligate bacterial parasites that can be stably passaged in coculture with specific species of host bacteria. Isolating these important members of the human oral microbiome, and many natural environments, requires abandoning many of Koch's concepts and methods and embracing novel microbiological approaches.
地球上绝大多数细菌尚未得到培养。有许多细菌门类没有已培养的实例，包括候选门辐射类群的大多数成员，但口腔中分离出的属于糖菌门的人类菌株除外。
本研究的目的是开发可重复的方法并验证培养人类口腔糖菌的方法，并找出在这些细菌被发现20年后仍延迟其分离的概念性陷阱。
将口腔样本分散并通过0.2微米的膜过滤器。将滤液中的超小糖菌细胞沉淀，接种到潜在细菌宿主细胞的肉汤培养物中，每2 - 3天传代到新鲜培养基中。
从 门中分离出32株代表4种糖菌的菌株，它们与3种宿主细菌稳定共培养。获得了16株菌株的完整基因组序列。
人类口腔糖菌是专性细菌寄生虫，可与特定种类的宿主细菌稳定共培养传代。分离这些人类口腔微生物群以及许多自然环境中的重要成员，需要摒弃科赫的许多概念和方法，采用新颖的微生物学方法。
