Comparison of seven protocols to identify fecal contamination sources using Escherichia coli

Stoeckel, D. M.; Mathes, M. V.; Hyer, K. E.; Hagedorn, C.; Kator, H.; Lukasik, J.; O'Brien, T. L.; Fenger, T. W.; Samadpour, M.; Strickler, K. M.; Wiggins, B. A.

Abstract:

Microbial source tracking (MST) uses various approaches to classify fecal-indicator microorganisms to source hosts. Reproducibility, accuracy, and robustness of seven phenotypic and genotypic MST protocols were evaluated by use of Escherichia coli from an eight-host library of known-source isolates and a separate, blinded challenge library. In reproducibility tests, measuring each protocol‘s ability to reclassify blinded replicates, only one (pulsed-field gel electrophoresis; PFGE) correctly classified all test replicates to host species; three protocols classified 48-62% correctly, and the remaining three classified fewer than 25% correctly. In accuracy tests, measuring each protocol‘s ability to correctly classify new isolates, ribotyping with EcoRI and PvuII approached 100% correct classification but only 6% of isolates were classified; four of the other six protocols (antibiotic resistance analysis, PFGE, and two repetitive-element PCR protocols) achieved better than random accuracy rates when 30-100% of challenge isolates were classified. In robustness tests, measuring each protocol‘s ability to recognize isolates from nonlibrary hosts, three protocols correctly classified 33-100% of isolates as "unknown origin," whereas four protocols classified all isolates to a source category. A relevance test, summarizing interpretations for a hypothetical water sample containing 30 challenge isolates, indicated that false-positive classifications would hinder interpretations for most protocols. Study results indicate that more representation in known-source libraries and better classification accuracy would be needed before field application. Thorough reliability assessment of classification results is crucial before and during application of MST protocols.

Genre:

Article

ProdID:

70026361

Citation Author:

Stoeckel, D. M.; Mathes, M. V.; Hyer, K. E.; Hagedorn, C.; Kator, H.; Lukasik, J.; O'Brien, T. L.; Fenger, T. W.; Samadpour, M.; Strickler, K. M.; Wiggins, B. A.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

6117

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Environmental Science and Technology

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Comparison of seven protocols to identify fecal contamination sources using Escherichia coli; 2004; Article; Journal; Environmental Science and Technology; Stoeckel, D. M.; Mathes, M. V.; Hyer, K. E.; Hagedorn, C.; Kator, H.; Lukasik, J.; O‘Brien, T. L.; Fenger, T. W.; Samadpour, M.; Strickler, K. M.; Wiggins, B. A.