Figure 2.

Genotyping Shiga toxin-producing Escherichia coli (STEC) with low-density DNA microarrays and the ampliPHOX colorimetric method. STEC reference strains from clinical or environmental sources with different genotypes (Table 1) were analyzed by 30-mer oligonucleotide DNA microarrays and the ampliPHOX colorimetric method. The panels, shown under strain designations, illustrate polymer formation on spotted probes for microarrays hybridized with amplification reactions testing a particular STEC reference strain or controls lacking a DNA template. The array layout shows the duplicate spots with probes targeting the O-antigen and virulence genes that are represented in groups 1–4. Biotinylated probes spotted along the top, middle and bottom rows (dark gray) of the array layout correspond to positive controls for polymer formation.