Mucinivorans hirudinis gen. nov., sp. nov., an anaerobic, mucin-degrading bacterium isolated from the digestive tract of the medicinal leech Hirudo verbana

<jats:p>Three anaerobic bacterial strains were isolated from the digestive tract of the medicinal leech<jats:italic>Hirudo verbana</jats:italic>, using mucin as the primary carbon and energy source. These strains, designated M3<jats:sup>T</jats:sup>, M4 and M6, were Gram-stain-negative, non-spore-forming and non-motile. Cells were elongated bacilli approximately 2.4 µm long and 0.6 µm wide. Growth only occurred anaerobically under mesophilic and neutral pH conditions. All three strains could utilize multiple simple and complex sugars as carbon sources, with glucose fermented to acid by-products. The DNA G+C contents of strains M3<jats:sup>T</jats:sup>, M4 and M6 were 44.9, 44.8 and 44.8 mol%, respectively. The major cellular fatty acid of strain M3<jats:sup>T</jats:sup>was iso-C<jats:sub>15 : 0</jats:sub>. Phylogenetic analysis of full-length 16S rRNA gene sequences revealed that the three strains shared >99 % similarity with each other and represent a new lineage within the family<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="family" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.8010" xlink:type="simple"><jats:italic>Rikenellaceae</jats:italic></jats:ext-link></jats:named-content>of the order<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="order" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.7929" xlink:type="simple"><jats:italic>Bacteroidales</jats:italic></jats:ext-link></jats:named-content>, phylum<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="phylum" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.7927" xlink:type="simple"><jats:italic>Bacteroidetes</jats:italic></jats:ext-link></jats:named-content>. The most closely related bacteria to strain M3<jats:sup>T</jats:sup>based on 16S rRNA gene sequences were<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="species" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.8012" xlink:type="simple"><jats:italic>Rikenella microfusus</jats:italic></jats:ext-link></jats:named-content>DSM 15922<jats:sup>T</jats:sup>(87.3 % similarity) and<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="species" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.8014" xlink:type="simple"><jats:italic>Alistipes finegoldii</jats:italic></jats:ext-link></jats:named-content>AHN 2437<jats:sup>T</jats:sup>(87.4 %). On the basis of phenotypic, genotypic and physiological evidence, strains M3<jats:sup>T</jats:sup>, M4 and M6 are proposed as representing a novel species of a new genus within the family<jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="family" xlink:type="simple"><jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.8010" xlink:type="simple"><jats:italic>Rikenellaceae</jats:italic></jats:ext-link></jats:named-content>, for which the name<jats:italic>Mucinivorans hirudinis</jats:italic>gen. nov., sp. nov. is proposed. The type strain of<jats:italic>Mucinivorans hirudinis</jats:italic>is M3<jats:sup>T</jats:sup>( = ATCC BAA-2553<jats:sup>T</jats:sup> = DSM 27344<jats:sup>T</jats:sup>).</jats:p>