Long-term survival of Escherichia coli O157 on pasture following an outbreak associated with sheep at a scout camp.
OBJECTIVE
To monitor the decay of E. coli O157 in soil (loamy sand) on a scout campsite following an outbreak in humans.


RESULTS
Samples of soil and sheep faeces were collected from the campsite and tested for the presence of E. coli O157 by immunomagnetic separation (IMS) after enrichment in buffered peptone water + vancomycin at 42 degrees C for 6 h. Enumeration of target was carried out by direct plating onto sorbitol MacConkey agar plates supplemented with cefixime and tellurite (CTSMAC) incubated at 37 degrees C for 24 h. Low numbers (< 100 g(-1)) were estimated by the most probable number (3-tube MPN) technique.


CONCLUSIONS
Survival was observed for 15 weeks.


CONCLUSIONS
A number of laboratory studies have followed the decay of E. coli O157 in soil, animal faeces and water. This study follows (for the first time) the decay of the organism in soil after an outbreak associated with sheep. It demonstrates the long-term persistence of the organism in the environment and the results will be potentially important in performing risk assessments for both human and animal infection.
Ogden
I D
ID
Department of Medical Microbiology, University of Aberdeen, Foresterhill, Aberdeen, UK. i.ogden@abdn.ac.uk
Hepburn
N F
NF
MacRae
M
M
Strachan
N J C
NJ
Fenlon
D R
DR
Rusbridge
S M
SM
Pennington
T H
TH
D000818:Animals; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D006801:Humans; D018189:Immunomagnetic Separation; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology; D012988:Soil Microbiology; D013997:Time Factors