PCR Primers Designed from the UidA Gene Sequence for the Detection of Escherichia coli O157:H7

One of the uniqueness of Escherichia coli O157:H7 is it inability to ferment sorbitol in 24 h and its negative test with the MUG assay, although this organism carried the UidA gene which encodes for -glucuronidase in its chromosome. Primers were designed based on the sequence of the -glucuronidase gene and were evaluated in a polymerase chain reaction assays as a marker to detect E. coli O157:H7. Of the three pairs of primers tested, which produces the estimated product size of 352, 271 and 353 bp respectively, one primer pairs (UidA2F & UidA2R) was found to be more specific and useful as a marker in combination with a published primer for the H7 gene for the detection of Escherichia coli O157:H7.