Abstract on E. coli fingerprinting

["Richard L Whitman" <richard_whitman@usgs.gov>]

Here is a very interesting abstract to an article where the researches
studied the ribotyping  variation (fingerprinting) within herds of cattle.
They conclude, " Our results suggest that for a host origin data base to be
effective, a large number of (>900) of E. coli isolates may need to be
ribotyped for each host, and the data base may need to be established as
contemporaneously as possible to the collection of environmental samples."

This sounds like quite a daunting and expensive task, if they are right.


---- Forwarded by Richard L Whitman/BRD/USGS/DOI on 03/05/2003 01:14 PM
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                      Muruleedhara                                                                         
                      Byappanahali             To:       Richard_Whitman@usgs.gov                          
                                               cc:                                                         
                      03/05/2003 11:55         Subject:  Abstract!                                         
                      AM                                                                                   
                                                                                                           
                                                                                                           



Journal of Environmental Quality 32:305-309 (2003)
© 2003 American Society of Agronomy, Crop Science Society of America, and
Soil Science
Society of America

TECHNICAL REPORTS
Surface Water Quality

Putative Temporal Variability of Escherichia coli
Ribotypes from Yearling Steers

M. B. Jenkins*,a, P. G. Hartelb, T. J. Olexaa and J. A. Stuedemanna

a USDA-ARS, J. Phil Campbell, Sr., Natural Resource Conservation Center,
Watkinsville, GA
30677
b Dep. of Crop and Soil Sciences, Univ. of Georgia, Athens, GA 30602

* Corresponding author (mjenkins@arches.uga.edu)

Received for publication March 11, 2002. Escherichia coli is a ubiquitous
component of the intestinal microflora of warm-blooded
animals, and is an indicator of fecal contamination of surface waters.
Ribotype profiling of E. coli is one of several genotypic
methods that has been developed to determine the host origin of fecal
bacteria. Like most genotypic methods of source tracking,
ribotyping requires a host origin database to identify environmental
isolates. To determine the extent of temporal variability of
ribotypes and its effect on a host origin database, E. coli isolates were
obtained from fecal samples of two herds of Black Angus
steers at a long-term experimental site at four sampling times from October
1999 to July 2000. Fecal samples were taken from six
randomly chosen steers at each time. At a similarity index of 90% as
calculated by unweighted pair-group method using arithmetic
averages (UPGMA), 240 ribotypes were identified from 451 E. coli isolates.
Only 20 ribotypes (8.3%), comprising 33% of the
total isolates, were shared among sampling times and were considered
resident ribotypes. Two of the twenty resident ribotypes
appeared at three sampling times, and the remaining eighteen appeared at
two. The majority of the ribotypes, therefore, were
transient and unique to each sampling time and steer. Both the apparent
turnover of E. coli ribotypes and a clonal diversity index
of 0.97 (indicative of extensive ribotype variability) suggest the
necessity of ribotyping a large number E. coli isolates per host to
establish a host origin database that is independent of temporal
variability, or complete enough to be effective.

Abbreviations: ATCC, American Type Culture Collection ? ET, electrophoretic
type







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