NCCOS Project Explorer (NPE)

Coliform Source Identification for Coastal Resource Manager Decision Making(2005)

Project Description:
Increased urbanization along coasts causes deleterious effects on nearby ecosystems. Microbes from nonpoint source contamination can enter coastal oceans via agricultural and urban surface runoff, wastewater discharges, storm water drainage systems, and domestic and wild animals. The presence of fecal bacteria in water indicates that disease-causing pathogens may be present. Fecal microbes include enteric bacteria such as Escherichia coli, Salmonella sp. and Shigella sp., enteric viruses include Noroviruses, Hepatitis A and some Caliciviruses. Human exposure to these pathogens occurs by ingesting contaminated seafood or seawater, or by exposure of open wounds to contaminated water. The risk of human exposure can be particularly high at beaches, tidal creeks, and estuaries, where human exposure occurs through recreational activities. Traditional detection methods for microorganisms of public health concern rely on microscopy or cultivation of indicator microorganisms. Assays of indicator bacteria, i.e. coliforms or enterococcus, are inadequate, slow (requiring over 24 hours to obtain results), and do not provide information about pollution sources. Another problem with the indicator system is that their detection may not be indicative of all pathogenic microbes, particularly viruses and protozoa. There is a critical need to develop more rapid, cost effective, and specific microbial methods to assess pathogen presence in coastal oceans, to estimate risk of exposure among susceptible persons, and to track the sources of microbial pollution so that effective remediation strategies and more accurate risk analyses can be developed. Three types of molecular assays (Luminex xMap™ technology, real-time PCR, and reverse transcription PCR) are being developed for direct detection of microbial pathogens and enteric viruses from marine waters and seafood. These techniques will allow rapid, cost effective, and specific identification of species and genotypes of marine microorganisms of public health significance. These new methods will aid in understanding the fate, transport, and load of the selected microorganisms in coastal ecosystems; identify host sources of contamination; provide data to resource managers; and ultimately identify best management practices to reduce the numbers of pathogens that present a threat to public health in coastal water systems. Additionally, rapid and direct detection of multiple pathogens could enable managers to open or close beaches/shellfish harvesting areas based on more substantial data than is currently available. Decisions could be made based on potential exposures to pathogens and associated human health risk rather than on detection of traditional indicator microorganisms.

Expected Outcome:
This research will develop and evaluate methods for the detection and source identification of fecal coliform bacteria in estuarine waters. Identification of the sources of fecal coliform bacteria will assist coastal managers in the development of strategies to control inputs of these contaminants which impact coastal resources.