Specific detection of Escherichia coli isolated from water samples using polymerase chain reaction targeting four genes: cytochrome bd complex, lactose permease, beta-D-glucuronidase, and beta-D-galactosidase.

AIMS: To develop a PCR-based method for reliable detection of Escherichia coli that enables its differentiation from biochemically and phylogenetically related bacteria. METHODS AND
RESULTS: Using multiplex PCR targeting four genes (cytochrome bd complex, lactose permease, beta-d-glucuronidase, and beta-d-galactosidase) the possibility of specific detection of various control E. coli strains was tested. It was found that four PCR fragments of the predicted size were observed only for E. coli strains, but not for relatives as close as Shigella sp. or other enterobacteria. Not surprisingly, this method enabled us to identify also E. coli strains which did not exhibit the beta-d-glucuronidase activity. Our multiplex PCR was also successfully used for identification of 95 environmental isolates of E. coli.
CONCLUSIONS: The developed PCR-based method, in which four genes coding for lactose permease, cytochrome bd complex, beta-d-glucuronidase, and beta-d-galactosidase, serve as target DNA sequences, allows precise and reliable detection of E. coli strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The suggested approach increases the specificity of detection of E. coli since it enables to distinguish E. coli from Shigella sp. and other relative enterobacteria.