TR-493 Expansion and Evaluation of Texas’ Bacterial Source Tracking Program

Authors: G.D. Di Giovanni, E.A. Casarez, J. A. Truesdale,T.J. Gentry, P. Wanjugi, E. Martin, K. Wagner

Significant progress was made in expanding and refining the Texas E. coli BST Library and updating the template-Standard Operating Procedures. In particular, additional known source isolates were added to address underrepresented wildlife species. Temporal stability evaluations using Leon River known source isolates collected over a 10-year period of time revealed that approximately half of the E. coli strains from known sources may change over time even within the same watershed. Similarly, temporal evaluation of E. coli water isolates from the Leon River watershed revealed similar temporal variability. Thus, it was not surprising that a fairly high amount of geographical variability was also found for known source isolates. However, source-specific isolates were also identified that have broader geographical distribution and temporal stability, which deserve further attention moving forward with library refinement.