Shiga Toxin–producing Escherichia coli Strains Negative for Locus of Enterocyte Effacement
Hayley J. Newton1, Joan Sloan1, Dieter M. Bulach, Torsten Seemann, Cody C. Allison, Marija Tauschek, Roy M. Robins-Browne, James C. Paton, Thomas S. Whittam, Adrienne W. Paton, and Elizabeth L. Hartland
Author affiliations: Monash University, Melbourne, Victoria, Australia (H.J. Newton, J. Sloan, D.M. Bulach, T. Seemann, C.C. Allison, E.L. Hartland); University of Melbourne, Melbourne (H.J. Newton, J. Sloan, M. Tauschek, R.M. Robins-Browne, E.L. Hartland); University of Adelaide, Adelaide, South Australia, Australia (J.C. Paton, A.W. Paton); Michigan State University, East Lansing, Michigan, USA (T.S. Whittam)
Figure 4. Phylogenetic relationships of 17 locus of enterocyte effacement (LEE)–negative and 13 LEE-positive Shiga toxin–producing Escherichia coli (STEC) strains (highlighted in gray) compared with a cohort of reference E. strains. Phylogeny was demonstrated by a neighbor-joining algorithm from 7 housekeeping gene sequences. Each isolate has been assigned a sequence type (ST) (in boldface), and assigned clonal groups (CGs) are displayed. The scale bar demonstrates the branch length that corresponds to 2 nucleotide substitutions per 1,000 nucleotide sites. 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.
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