title: O157:H7 and O104:H4 Vero/Shiga toxin-producing Escherichia coli outbreaks: respective role of cattle and humans.
abstract: An enteroaggregative Verotoxin (Vtx)-producing Escherichia coli strain of serotype O104:H4 has recently been associated with an outbreak of haemolytic-uremic syndrome and bloody diarrhoea in humans mainly in Germany, but also in 14 other European countries, USA and Canada. This O104:H4 E. coli strain has often been described as an enterohaemorrhagic E. coli (EHEC), i.e. a Vtx-producing E. coli with attaching and effacing properties. Although both EHEC and the German O104:H4 E. coli strains indeed produce Vtx, they nevertheless differ in several other virulence traits, as well as in epidemiological characteristics. For instance, the primary sources and vehicles of typical EHEC infections in humans are ruminants, whereas no animal reservoir has been identified for enteroaggregative E. coli (EAggEC). The present article is introduced by a brief overview of the main characteristics of Vtx-producing E. coli and EAggEC. Thereafter, the O104:H4 E. coli outbreak is compared to typical EHEC outbreaks and the virulence factors and host specificity of EHEC and EAggEC are discussed. Finally, a renewed nomenclature of Vtx-producing E. coli is proposed to avoid more confusion in communication during future outbreaks and to replace the acronym EHEC that only refers to a clinical condition.
authors.affiliation: Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium. JG.Mainil@ulg.ac.be.
authors.forename: Denis
authors.initials: D
authors.lastname: Piérard
authors.forename: Henri
authors.initials: H
authors.lastname: De Greve
authors.forename: Freddy
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: Jacques
authors.initials: J
authors.lastname: Mainil
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000145:classification / Q000472:pathogenicity / Q000502:physiology; D005060:Europe / Q000453:epidemiology; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D009656:North America / Q000453:epidemiology; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D014774:Virulence