AWWA WQTC60709

Nonpoint sources (NPS) of pollution can greatly impact water quality. One keycomponent in effectively implementing a NPS pollution management program is theidentification and assessment of human and animal sources of bacterial contamination.Fecal coliform bacteria, including Escherichia coli (E. coli), have extensively been usedas an indicator of fecal pollution and the potential presence of other pathogenicmicroorganisms in water. E. coli is a common inhabitant of animal and human intestinesand recent studies have shown that isolates from humans and various host animals (e.g.cattle, chickens, and pigs) may differ genetically and phenotypically. Analysis of E. coliisolates using genetic and biochemical tests may allow the original host animal to beidentified, referred to as bacterial source tracking (BST). In the last few years there hasbeen a tremendous amount of progress in the development and evaluation of BSTmethods, however, the scientific literature is full of conflicting reports. There is alsosignificant controversy over the selection of the single, most useful BST method and therecent research suggests that multiple techniques may be the most successful. Moleculartools appear to hold the greatest promise for BST, providing the most conclusivecharacterization and level of discrimination for isolates. Antibiotic resistance analysis, aphenotypic characterization method, also has the potential to identify the human oranimal origin of isolates. However, reference "libraries" of bacterial genetic fingerprintsand antibiotic resistance profiles are needed to correctly identify the source of bacteriaisolated from environmental water samples. Our laboratory is currently the lead on twoTexas state-funded projects that include the development of E. coli bacterial sourcetracking libraries. Several thousand isolates are being characterized by automatedribotyping using the Qualicon RiboPrinter, repetitive sequence polymerase chain reaction(ERIC-PCR), pulsed field gel electrophoresis (PFGE) and antibiotic resistance analysis(ARA). Fingerprint patterns are being compared using multiple statistical tools todetermine discrimination of sources and congruence of the different methods. Thecombination of ERIC-PCR, RiboPrinter ribotyping, PFGE, and ARA, will provide one ofthe most comprehensive BST libraries of environmental E. coli isolates. This multiphasicapproach will allow the state of Texas to keep pace with developments in BSTtechnology. By using standardized and automated methods, the libraries can be expandedthrough future projects and data shared with other investigators and regulatory agencies.Recent analysis of a model data set illustrated the need for cautious interpretation. Forexample, different similarity clusters were formed using the RiboPrinter softwarecompared to BioNumerics bioinformatics software. A description of the approach takenfor two BST projects in Texas and data analysis challenges are presented. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

6

File Size:

1 file , 740 KB