Genotyping Escherichia coli Isolates from Duck, Goose, and Gull Fecal Samples with Phylogenetic Markers using Multiplex Polymerase Chain Reaction for Application in Microbial Source Tracking

Multiplex polymerase chain reaction with phylogenetic markers, chuA, yjaA, and TspE4.C2 along with virulence gene, eae, was performed for determination of genotypic differences in Escherichia coli isolated from gull, goose, and duck. Results showed that isolates from goose frequently contained TspE4.C2 and an unknown 600 bp product (87%) whereas isolates from gull and duck contained varied combinations of the three phylogenetic markers. In seven of the 15 duck samples, all three phylogenetic markers were present as in human E. coli isolates. Similar results were evident in two of the 15 gull samples. In addition to amplification of the unidentified 600 bp product, a 1500 bp product was observed in five of the 45 isolates tested. None of the isolates contained eae. Due to genotypic variations in gull and duck E. coli isolates, the multiplex PCR method studied would not be able to positively identify hosts for general or robust use in microbial source tracking.