Year: 2010
Type: article
Abstract: Microbial communities are each a composite of populations whose presence and relative abundance in water or other environmental samples are a direct manifestation of environmental conditions, including the introduction of microbe-rich fecal material and factors promoting persistence of the microbes therein.As shown by culture-independent methods, different animal-host fecal microbial communities appear distinctive, suggesting that their community profiles can be used to differentiate fecal samples and to potentially reveal the presence of host fecal material in environmental waters.Cross-comparisons of microbial communities from different hosts also reveal relative abundances of genetic groups that can be used to distinguish sources.In increasing order of their information richness, several community analysis methods hold promise for MST applications: phospholipid fatty acid (PLFA) analysis, denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (TRFLP), cloning/sequencing, and PhyloChip.Specific case studies involving TRFLP and PhyloChip approaches demonstrate the ability of community-based analyses of contaminated waters to confirm a diagnosis of water quality based on host-specific marker(s).The success of community-based MST for comprehensively confirming fecal sources relies extensively upon using appropriate multivariate statistical approaches.While community-based MST is still under evaluation and development as a primary diagnostic tool, results presented herein demonstrate its promise.Coupled with its inherently comprehensive ability to capture an unprecedented amount of microbiological data that is relevant to water quality, the tools for microbial community analysis are increasingly accessible, and community-based approaches have unparalleled potential for translation into rapid, perhaps real-time, monitoring platforms.coastal waters continuously receiving sewage (Cabelli et al. 1982).Now, most wastewaters in the U.S. are treated to either primary or secondary standards (National Research Council 1993), and, except for acute short-term sewage spills, sources of human waste are diffuse, e.g. from leaking sewer pipes, cross-connections to storm drains, or failed septic systems.The disadvantages in relying on FIB for diffuse, or non-point, source monitoring arise primarily from the fact that FIB are nonspecific as to source, e.g. to human waste which is most relevant as a carrier for human pathogens.While total maximum daily load (TMDL) compliance is a major driver for microbial source tracking (MST; (U.S. Environmental Protection Agency 2005)), another is the non-specificity of FIB to human or other wastes.Other disadvantages of FIB, including the method's reliance on cultivation when FIB can become nonculturable in the environment (Leadbetter 1997), partly motivate the subject of this chapter: i.e. cultureindependent microbial community analysis as a MST approach.Lastly, and related to the nonspecificity of FIB to source, some FIB can become indigenous, e.g. to plant surfaces (Hazen 1988) and to beach sands (Ishii et al. 2007), which results in false positive indications of an increased risk of pathogen presence.Each of these disadvantages contributes to the rate of error associated with FIB monitoring for predicting pathogen presence and protecting public health.Thus, while one MST objective may be discovering the sources of FIB, which is particularly pertinent to TMDL applications (U.S. Environmental Protection Agency 2005), another view, particularly in light of the fundamental problems with interpreting FIB environmental data, is that MST should be mainly motivated by discovering 1) if fecal material is present, 2) the host source of fecal material, and 3) the geographical origin of fecal material.
Authors: Cao, Y., Wu, C. H., Andersen, G. L., Holden, P. A.
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1648088953