FIG. 1.

Unrooted neighbor-joining phylogenetic tree obtained from the nucleotide multiple alignment of the C. difficile tet(W) gene identified in this study and other 13 tet(W) gene sequences available in GenBank. Among the species included are Megasphaera elsdenii, Selenomonas ruminantium, Arcanobacterium pyogenes, and Mitsuokella multiacida. The branch lengths are scaled in proportion to the extent of the change per position, as indicated by the scale bar. GenBank accession numbers are in parentheses.