Use of antibiotic resistance analysis for representativeness testing of multiwatershed libraries.
The use of antibiotic resistance analysis (ARA) for microbial source tracking requires the generation of a library of isolates collected from known sources in the watershed. The size and composition of the library are critical in determining if it represents the diversity of patterns found in the watershed. This study was performed to determine the size that an ARA library needs to be to be representative of the watersheds for which it will be used and to determine if libraries from different watersheds can be merged to create multiwatershed libraries. Fecal samples from known human, domesticated, and wild animal sources were collected from six Virginia watersheds. From these samples, enterococci were isolated and tested by ARA. Based on cross-validation discriminant analysis, only the largest of the libraries (2,931 isolates) were found to be able to classify nonlibrary isolates as well as library isolates (i.e., were representative). Small libraries tended to have higher average rates of correct classification, but were much less able to correctly classify nonlibrary isolates. A merged multiwatershed library (6,587 isolates) was created and was found to be large enough to be representative of the isolates from the contributing watersheds. When isolates that were collected from the contributing watersheds approximately 1 year later were analyzed with the multiwatershed library, they were classified as well as the isolates in the library, suggesting that the resistance patterns are temporally stable for at least 1 year. The ability to obtain a representative, temporally stable library demonstrates that ARA can be used to identify sources of fecal pollution in natural waters.
Wiggins
Bruce A
BA
Department of Biology, James Madison University, Harrisonburg, Virginia 22807, USA. wigginba@jmu.edu
Cash
Philip W
PW
Creamer
Wes S
WS
Dart
Scott E
SE
Garcia
Preston P
PP
Gerecke
Todd M
TM
Han
Jennifer
J
Henry
Brian L
BL
Hoover
Kylie B
KB
Johnson
Erika L
EL
Jones
K C
KC
McCarthy
Jacquie G
JG
McDonough
Justin A
JA
Mercer
Sarah A
SA
Noto
Michael J
MJ
Park
Haewon
H
Phillips
Matthew S
MS
Purner
Stephanie M
SM
Smith
Brian M
BM
Stevens
Erin N
EN
Varner
Amy K
AK
D000818:Animals; D000829:Animals, Domestic; D000835:Animals, Wild; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D016983:Enterococcus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005618:Fresh Water / Q000382:microbiology*; D015723:Gene Library; D006801:Humans; D012423:Rural Health; D014504:Urban Health; D014873:Water Pollutants
D000900:Anti-Bacterial Agents; D014873:Water Pollutants