FIG. 2.

Detection of virulence genes and simultaneous identification of the pathotypes of known E. coli strains after microarray hybridization with genomic DNA from nonpathogenic K-12 strain E. coli DH5α (A), enterohemorrhagic strain EDL933 O157:H7 (B), uropathogenic strain J96 O4:K6 (C), and enterotoxigenic strain H-10407 (D). After HindIII-EcoRI digestion, genomic DNA was labeled with Cy3. Labeled DNA (500 ng) was hybridized to the array overnight at 42°C, washed, dried, and scanned. The boxed spots in panel A represent the virulence genes present in E. coli K-12 strain DH5α (traT, fimA, fimH, ompA, ompT, iss, and fliC). The boxed spots in panels B, C, and D indicate the pathotype-specific genes in the strains tested. Genes present in more than one pathotype (iss, irp2, fliC, and ompT) or present in all pathotypes (fimH, fimA, and ompA) gave positive signals. The horizontal bar indicates the color representation of the fluorescence signal intensity.