Addition of Avian and Equine Tests Used for Microbial Source Tracking at KSU

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 and the family Lachnospiraceae. They are strict anaerobes found in large quantities in the intestines of animals. Both bacterial groups 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 and Lachnospiraceae 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- and Lachnospiraceae-based species-specific assays that identify the presence of gene sequences uniquely found in these bacteria that are associated with their corresponding host species. We have previously implemented three MST tests: human-specific, dog-specific, and total animal. Here, we attempted to add bird-specific and horse-specific tests to our collection. Our experiments confirmed the ability of each new test to detect their target genes, and at a level of detection and quantification similar to that of previously published results. We now have the ability to quantitatively assess the level of species-specific contamination in the environment using five MST tests: human, dog, bird, horse, and total animal. We hope to continue to add new species tests to our MST toolbox in the future