Animal host associated differences in Shiga toxin-producing Escherichia coli isolated from sheep and cattle on the same farm.
OBJECTIVE
To investigate if cattle on the same farm as sheep are a possible risk factor for stx in sheep and to determine whether or not sheep and cattle on the same farm share the same stx pool.


RESULTS
Faecal samples from sheep and cattle were screened for stx by polymerase chain reaction (PCR). Of these samples, 87.6 and 64.6% were stx positive in sheep and cattle, respectively. There was no difference in stx occurrence in sheep from farms with or without cattle. From stx positive samples, 118 Shiga toxin-producing Escherichia coli (STEC) isolates were recovered by a filter-hybridization method. Serotyping, PCR and pulsed-field gel electrophoresis (PFGE) showed that there was a distinct association between serotypes, stx profiles and animal species.


CONCLUSIONS
Keeping animals together in pens, which enhances faecal-oral contact, is suggested as a possible explanation for the differences seen in stx occurrence. Sheep and cattle isolates are distinctly different in serotype and stx profile although isolated from the same farm, and are more related to isolates within the same serotype with the same stx profile than to isolates with different serotype from the same farm.


CONCLUSIONS
The study supports the animal-host relationship hypothesis suggested in other studies and indicates that the STEC sheep reservoir in Norway may not pose a serious public health risk.
Urdahl
A M
AM
Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033, Oslo, Norway. yngvild.wasteson@veths.no
Beutin
L
L
Skjerve
E
E
Zimmermann
S
S
Wasteson
Y
Y
D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002417:Cattle / Q000382:microbiology*; D004197:Disease Reservoirs / Q000662:veterinary; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000635:transmission; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D012307:Risk Factors; D012703:Serotyping / Q000379:methods; D012756:Sheep / Q000382:microbiology*; D022621:Shiga Toxin / Q000302:isolation & purification*; D037521:Virulence Factors / Q000235:genetics
D037521:Virulence Factors; D022621:Shiga Toxin