Cultivation of a human-associated TM7 phylotype reveals a reduced genome and epibiotic parasitic lifestyle

The candidate phylum TM7 is globally distributed and often associated with human inflammatory mucosal diseases. Despite its prevalence, the TM7 phylum remains recalcitrant to cultivation, making it one of the most enigmatic phyla known. In this study, we cultivated a TM7 phylotype (TM7x) from the human oral cavity. This extremely small coccus (200-300 nm) has a distinctive lifestyle not previously observed in human-associated microbes. It is an obligate epibiont of an Actinomyces odontolyticus strain (XH001) yet also has a parasitic phase, thereby killing its host. This first completed genome (705 kb) for a human-associated TM7 phylotype revealed a complete lack of amino acid biosynthetic capacity. Comparative…

• NI
  National Institute of General Medical Sciences

  Award: 1R01GM095373
• NI
  National Institute of Dental and Craniofacial Research

  Awards: 1R01DE020102, 1R01DE021108, DE022734, 1R01DE023810-01