Shiga Toxin–producing Escherichia coli Strains Negative for Locus of Enterocyte Effacement
Figure 3. Neighbor-joining tree of ehxA (A) and repA (B) as implemented in ClustalW (www.ebi.ac.uk/Tools/clustalw2). This rectangular cladogram demonstrates the distinct clades (shown by boxes) for ehxA that delineate locus of enterocyte effacement (LEE)–negative and LEE-positive Shiga toxin–producing Escherichia coli strains. Exceptions to this pattern are shown in boldface, strain names are shown in parentheses, and + or – indicates the presence or absence of LEE. Significant nodes were identified by bootstrapping (Monte Carlo randomization); nodes were present in >70% of the 1,000 bootstrap trees highlighted and identified as significant.