Figure. Phylogenetic tree based on the alignment of the surface layer protein A amino acid sequence of Clostridium difficile 027 (GenBank accession no. CBE06198) with those of PCR-ribotypes 001, 002, 005, 010, 012, 014, 017, 031, 046, 054, 066, 078, 092, and 094 (GenBank accession nos. AAZ05957, AAZ05964, AAZ05968, AAZ05974, AAZ05975, AAZ05984, AAZ05988, AAZ05989, AAZ05980, AAZ05972, AAZ05986, AAZ05994, AAZ05982, and AAZ05991, respectively). The phylogram was generated by using TreeView version 1.6.6 (http://en.bio-soft.net/tree/TreeView.html). The branch lengths are scaled in proportion to the extent of the change per position, as indicated by the scale bar.