title: Comparison of seven protocols to identify fecal contamination sources using Escherichia coli.
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% correctclassification 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
authors.affiliation: US Geological Survey, Columbus, Ohio 43229, USA. stoeckel@usgs.gov
authors.forename: Donald M
authors.initials: DM
authors.lastname: Stoeckel
authors.forename: Melvin V
authors.initials: MV
authors.lastname: Mathes
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Hyer
authors.forename: Charles
authors.initials: C
authors.lastname: Hagedorn
authors.forename: Howard
authors.initials: H
authors.lastname: Kator
authors.forename: Jerzy
authors.initials: J
authors.lastname: Lukasik
authors.forename: Tara L
authors.initials: TL
authors.lastname: O'Brien
authors.forename: Terry W
authors.initials: TW
authors.lastname: Fenger
authors.forename: Mansour
authors.initials: M
authors.lastname: Samadpour
authors.forename: Kriston M
authors.initials: KM
authors.lastname: Strickler
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Wiggins
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000145:classification* / Q000302:isolation & purification; D005189:False Positive Reactions; D005243:Feces / Q000382:microbiology*; D015723:Gene Library; D005838:Genotype; D006801:Humans; D010641:Phenotype; D015203:Reproducibility of Results; D021521:Ribotyping; D012680:Sensitivity and Specificity; D014871:Water Microbiology