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Microbial Source Tracking: Current and Future Molecular Tools in Microbial Water Quality Forensics
Citation:
SANTO-DOMINGO, J. W., R. Lamendella, AND N. ASHBOLT. Microbial Source Tracking: Current and Future Molecular Tools in Microbial Water Quality Forensics. Chapter 10, K. Sen and N. Ashbolt (ed.), Environmental Microbiology: Current Technology and Water Applications. ISBN: 978-1-904455-70-7 . Caister Academic Press, Norwich, Uk, , c. 310, (2010).
Impact/Purpose:
To inform the public.
Description:
Current regulations in the United States stipulate that the microbial quality of waters used for consumption and recreational activities should be determined regularly by measuring microbial indicators of fecal pollution. Hence, the microbial risk associated with these waters is determined using microbial indicators rather than by detecting pathogenic microorganisms. The use of these microbial surrogates is an important area of debate among public health risks officials and environmental research scientists. Detecting pathogens is a better choice; however, pathogens are often found in environmental samples in very low numbers. Most microbial indicators are of bacterial origin (e.g., fecal coliforms and enterococci), although bacteriophages are used in some cases as surrogates of viral human pathogens in shellfishing waters. While methods used to detect bacterial indicators provide an estimate of fecal pollution levels, they are not capable of discriminating among different pollution sources as the targeted bacteria are present in all types of fecal sources. In this chapter, we will discuss the use of molecular methods to track sources of fecal pollution in environmental waters and their emergence as an important tool in environmental monitoring. A general description of the most commonly used methods will be provided, and whenever appropriate, some of the advantages and limitations will be highlighted. The use of genomic technologies to develop new methods and to fill existing research gaps in source tracking and microbial water quality will be discussed in greater detail. The reader should keep in mind that the field of environmental microbiology is changing drastically as biotechnological tools are providing new means of describing the molecular diversity of populations relevant to environmental fecal pollution. While this is a dynamic field, emphasis will be placed on culture-independent methods relying on DNA-based targets that currently dominate the scientific literature.
