Quantification of Human-, Dog-, and Total Animal-associated Bacteroides in Cobb County Creeks

Presenters

Disciplines

Environmental Microbiology and Microbial Ecology | Molecular Genetics

Abstract (300 words maximum)

Microbial source tracking (MST) attempts to identify specific animal sources of fecal contamination in the environment. While traditional fecal coliform enumeration can give a general measure of contamination, the specificity imparted by modern MST provides a more informative assessment of contaminants and their likelihood to affect human health outcomes.

We have been developing a MST system that detects DNA biomarkers from the gram negative bacterial genus Bacteroides. They are strict anaerobes found in large quantities in the intestines of animals. Bacteroides cannot survive long periods outside of their hosts and are considered a good indicator of recent fecal contamination in environmental waters.

Unlike E. coli or Enteroccoccci, host-specific strains of Bacteroides exist. This can be attributed to their inability to proliferate outside of their hosts, resulting in a close relationship by which they evolve into species-specific strains. To this end, we have been developing Bacteroides-based species-specific assays that identify the presence of 16S rRNA gene sequences uniquely found in Bacteroides associated with their corresponding host species.

We tested three quantitative real-time Polymerase Chain Reaction (qPCR) assays for their ability to detect human-, dog-, and total animal-associated Bacteroides from environmental water samples. Our experiments confirmed their ability to quantitatively assess the level of contamination from these species in the environment. We are further refining our tests to include an internal amplification control to correct for PCR inhibition stemming from the environment. As we continue to optimized the qPCR assay, we hope to add new species tests to our MST toolbox.

Academic department under which the project should be listed

CSM - Molecular and Cellular Biology

Primary Investigator (PI) Name

Mike Beach

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Quantification of Human-, Dog-, and Total Animal-associated Bacteroides in Cobb County Creeks

Microbial source tracking (MST) attempts to identify specific animal sources of fecal contamination in the environment. While traditional fecal coliform enumeration can give a general measure of contamination, the specificity imparted by modern MST provides a more informative assessment of contaminants and their likelihood to affect human health outcomes.

We have been developing a MST system that detects DNA biomarkers from the gram negative bacterial genus Bacteroides. They are strict anaerobes found in large quantities in the intestines of animals. Bacteroides cannot survive long periods outside of their hosts and are considered a good indicator of recent fecal contamination in environmental waters.

Unlike E. coli or Enteroccoccci, host-specific strains of Bacteroides exist. This can be attributed to their inability to proliferate outside of their hosts, resulting in a close relationship by which they evolve into species-specific strains. To this end, we have been developing Bacteroides-based species-specific assays that identify the presence of 16S rRNA gene sequences uniquely found in Bacteroides associated with their corresponding host species.

We tested three quantitative real-time Polymerase Chain Reaction (qPCR) assays for their ability to detect human-, dog-, and total animal-associated Bacteroides from environmental water samples. Our experiments confirmed their ability to quantitatively assess the level of contamination from these species in the environment. We are further refining our tests to include an internal amplification control to correct for PCR inhibition stemming from the environment. As we continue to optimized the qPCR assay, we hope to add new species tests to our MST toolbox.