Serotypes and virulence factors of Shiga toxin-producing Escherichia coli isolated from healthy Norwegian sheep.
OBJECTIVE
To characterize a number of Shiga toxin-producing Escherichia coli (STEC) isolates from sheep and to discuss the potential of these isolates as human pathogens.


RESULTS
Twelve different O-groups and seven different H-types were identified by standard serotyping methods. The most common serotypes were O5:NM, O6:H10, O91:NM and O128:NM. Polymerase chain reaction (PCR) was used for the detection of virulence factor genes. Of 102 isolates, 86.3% carried stx1 and 83% of these were also positive in the stx1OX3-specific PCR. stx2 was carried by 55.9% of the isolates and 77.2% of these were also positive in the stx2d-specific PCR. The Vero cell assay showed high toxin production in 70.6% of the isolates. None of the isolates carried eae.


CONCLUSIONS
The study supports the animal-host relationship suggested in other studies with STEC serogroups O5, O91 and O128 strongly associated with sheep. Most sheep STEC carry stx1OX3 (except O91) and the dominating stx2 variant is stx2d. One stx profile clearly dominates within a serotype.


CONCLUSIONS
In spite of the predominance of certain sheep-associated STEC, sheep cannot be excluded as carriers of human pathogenic STEC.
Urdahl
A M
AM
Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, Oslo, Norway.
Beutin
L
L
Skjerve
E
E
Wasteson
Y
Y
D000818:Animals; D004197:Disease Reservoirs; D004926:Escherichia coli / Q000145:classification / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000635:transmission; D006801:Humans; D009664:Norway; D012703:Serotyping; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology* / Q000635:transmission; D022603:Shiga Toxins / Q000378:metabolism*; D014774:Virulence; D015047:Zoonoses
D022603:Shiga Toxins