The phylum synergistetes

Abstract

The phylum Synergistetes has been characterized in 2009 and currently groups 12 genera and 20 species of Gram-negative, anaerobic bacteria with various morphologies and metabolisms, i.e., Aminiphilus, Aminobacterium, Aminomonas, Anaerobaculum, Cloacibacillus, Dethiosulfovibrio, Fretibacterium, Jonquetella, Pyramidobacter, Synergistes, Thermanaerovibrio, and Thermovirga. In addition, the genus Acetomicrobium has to be reclassified as belonging to this phylum. Cells are mainly rods with various shapes and are characterized by their ability to utilize amino acids as source for energy. Low cultivability accounts for the global lack of knowledge on most members of this phylum, and data currently available mainly arise from cultivation-independent studies. It is noteworthy that members of Synergistetes are widely distributed but more usually represent a minor population within inhabited ecosystems. Four types of habitats could be delineated depending on isolate or clone origin, including sludge and wastewater from anaerobic digesters, natural springs, natural seawater and sulfur mats, water related to petroleum and gas production facilities, and host-associated microbiota, Synergistes being more usually recovered from a unique of these site types according to the taxon considered. Although no data are currently available regarding their virulence in different hosts, their recovery in various physiological and pathophysiological conditions witnessed for a probable opportunistic pathogenic behavior.