FIG. 1.

Representation of five open reading frames, two toxin genes (tcdA and tcdB), and three additional genes (tcdC, tcdD, and tcdE) of the PaLoc in strain VPI (toxinotype 0) in comparison to those of variant toxinotypes (toxinotypes I to X). The hatched areas represent the repetitive regions of both toxin genes. (A) Relative positions and sizes of 10 overlapping PCR fragments used to amplify the whole PaLoc sequence. (B) Schematic representation of length and restriction site polymorphisms found in different toxinotypes. Gray regions are those in which length polymorphisms were detected: deletions in the A3 fragments of toxinotypes I, II, VI, VII, and VIII or insertions in toxinotypes IV to X. Δ, relative positions and sizes (not in scale) of the deletions. Only some of the restriction sites tested in each PCR fragment are shown, and not all restriction sites of the same enzymes are shown (known for VPI 10463 sequence). A, AccI; Ec, EcoRV; E, EcoRI; H, HindIII; Hc, HincII; h, HaeIII; N, NsiI; Nc, NcoI; P, PstI; R, RsaI; S, SpeI.