16
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: not found
      • Article: not found

      Escherichia coli in the Environment: Implications for Water Quality and Human Health

      ,
      Microbes and Environments
      Japanese Society of Microbial Ecology

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Related collections

          Most cited references63

          • Record: found
          • Abstract: not found
          • Article: not found

          Role of nonhost environments in the lifestyles of Salmonella and Escherichia coli.

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Development of Bacteroides 16S rRNA gene TaqMan-based real-time PCR assays for estimation of total, human, and bovine fecal pollution in water.

            Bacteroides species are promising indicators for differentiating livestock and human fecal contamination in water because of their high concentration in feces and potential host specificity. In this study, a real-time PCR assay was designed to target Bacteroides species (AllBac) present in human, cattle, and equine feces. Direct PCR amplification (without DNA extraction) using the AllBac assay was tested on feces diluted in water. Fecal concentrations and threshold cycle were linearly correlated, indicating that the AllBac assay can be used to estimate the total amount of fecal contamination in water. Real-time PCR assays were also designed for bovine-associated (BoBac) and human-associated (HuBac) Bacteroides 16S rRNA genes. Assay specificities were tested using human, bovine, swine, canine, and equine fecal samples. The BoBac assay was specific for bovine fecal samples (100% true-positive identification; 0% false-positive identification). The HuBac assay had a 100% true-positive identification, but it also had a 32% false-positive rate with potential for cross-amplification with swine feces. The assays were tested using creek water samples from three different watersheds. Creek water did not inhibit PCR, and results from the AllBac assay were correlated with those from Escherichia coli concentrations (r2= 0.85). The percentage of feces attributable to bovine and human sources was determined for each sample by comparing the values obtained from the BoBac and HuBac assays with that from the AllBac assay. These results suggest that real-time PCR assays without DNA extraction can be used to quantify fecal concentrations and provide preliminary fecal source identification in watersheds.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Parallel evolution of virulence in pathogenic Escherichia coli.

              The mechanisms underlying the evolution and emergence of new bacterial pathogens are not well understood. To elucidate the evolution of pathogenic Escherichia coli strains, here we sequenced seven housekeeping genes to build a phylogenetic tree and trace the history of the acquisition of virulence genes. Compatibility analysis indicates that more than 70% of the informative sites agree with a single phylogeny, suggesting that recombination has not completely obscured the remnants of ancestral chromosomes. On the basis of the rate of synonymous substitution for E. coli and Salmonella enterica (4.7 x 10(-9) per site per year), the radiation of clones began about 9 million years ago and the highly virulent pathogen responsible for epidemics of food poisoning, E. coli O157:H7, separated from a common ancestor of E. coli K-12 as long as 4.5 million years ago. Phylogenetic analysis reveals that old lineages of E. coli have acquired the same virulence factors in parallel, including a pathogenicity island involved in intestinal adhesion, a plasmid-borne haemolysin, and phage-encoded Shiga toxins. Such parallel evolution indicates that natural selection has favoured an ordered acquisition of genes and the progressive build-up of molecular mechanisms that increase virulence.
                Bookmark

                Author and article information

                Journal
                Microbes and Environments
                Microb. Environ.
                Japanese Society of Microbial Ecology
                1342-6311
                1347-4405
                2008
                2008
                : 23
                : 2
                : 101-108
                Article
                10.1264/jsme2.23.101
                21558695
                d0102b3f-1bf4-406d-9236-5432425760f8
                © 2008
                History

                Comments

                Comment on this article