FIG. 1.

The dendrogram created when the 23-locus binary fingerprint of each of the 79 E. coli O157:H7 strains and non-O157:H7 strain K-12 MG1655 were clustered using Bionumerics version 5.1. A black square represents the presence of a locus and a white square represents the absence of a locus, as determined by PCR. Sequence data for EDL933 indicate that locus fprn16 of OI#93/S-loop#153 is homologous to that of Sakai; however, repeated efforts to amplify fprn16 in EDL933 were unsuccessful. Similarly, previous work with the Sakai strain used in this study has shown a deletion of fprn29 in OI#57/S-loop#108.