FIG. 1.

Dendrogram representation of virulence, specific, and common gene patterns for E. coli pathotypes. Hierarchical clustering was obtained by using Avadis software. The pathotype virulence and specific genes are indicated with different colors to denote the specificity of pathotypes in the dendrogram. Fifteen EHEC, 17 EPEC, 36 UPEC, and 11 EAEC virulence gene probes were derived from strains EDL933, E2348/69, CFT073, and O42, respectively. Twenty-three EHEC-EPEC virulence gene probes were obtained from EPEC E2348/69. Sixty EHEC-specific genes, 61 UPEC-specific genes, and 40 nonpathogenic E. coli-specific genes were from strains EDL933, CFT073, and K-12, respectively. Gene probes that show no signals for 24 UPEC-specific gene probes and also 81 Salmonella core genes (negative control) were also included in the dendrogram. The results for four nonreactive virulence gene probes of meningitis-causing E. coli are not included in the dendrogram. The diversity between EHEC and EPEC in certain regions of EHEC-EPEC is also represented as a pattern profile in the dendrogram. All the reference and clinical isolates except the ETEC and EAEC isolates contained conserved virulence and specific genes; the ETEC and EAEC isolates contained heterogeneous virulence genes. However, the uniqueness of ETEC and EAEC toxins and virulence genes is evident in the pattern profile of the dendrogram.