RAPD profiles of selected Escherichia coli isolates. Lane numbers are shown below the gel image. Lanes 4 and 17, 250-bp marker (M); lanes 1 to 3 and 5 to 16, CGA-positive sewage isolates; lanes 18 and 19, CGA positive controls (human cystitis isolates SEQ102 and UMN026, respectively); lanes 20 to 24, CGA negative controls (lanes 20 and 21, non-CGA sewage isolates [from phylogenetic groups B2 and D, respectively]; lane 22, strain CFT073 [from group B2]; and lanes 23 and 24, human-source non-CGA isolates [from groups D and B2, respectively]). Bullets above lanes indicate CGA isolates that exhibit the consensus CGA-associated virulence profile, including the F16 papA (P fimbria structural subunit) allele, and a characteristic CGA-associated RAPD profile. CGA isolates in lanes without bullets exhibit an atypical virulence profile that includes the F10 papA allele plus (except for strain 492 [lane 5]) an atypical RAPD profile that includes an extra, ∼2,000-bp band (vertical arrows; “*” for strain 492 [lane 5]). The profiles of all the CGA isolates are indistinguishable (within the reproducibility limits of RAPD analysis), except for the ∼2,000-bp band, and collectively, they are distinct from the profiles of the non-CGA isolates, each of which is unique.