RESUMEN
In summer 2013, an excess of paediatric cases of haemolytic uraemic syndrome (HUS) in a southern region of Italy prompted the investigation of a community-wide outbreak of Shiga toxin 2-producing Escherichia coli (STEC) O26:H11 infections. Case finding was based on testing patients with HUS or bloody diarrhoea for STEC infection by microbiological and serological methods. A case-control study was conducted to identify the source of the outbreak. STEC O26 infection was identified in 20 children (median age 17 months) with HUS, two of whom reported severe neurological sequelae. No cases in adults were detected. Molecular typing showed that two distinct STEC O26:H11 strains were involved. The case-control study showed an association between STEC O26 infection and consumption of dairy products from two local plants, but not with specific ready-to-eat products. E.coli O26:H11 strains lacking the stx genes were isolated from bulk milk and curd samples, but their PFGE profiles did not match those of the outbreak isolates. This outbreak supports the view that infections with Stx2-producing E. coli O26 in children have a high probability of progressing to HUS and represent an emerging public health problem in Europe.
Asunto(s)
Brotes de Enfermedades , Infecciones por Escherichia coli/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Síndrome Hemolítico-Urémico/microbiología , Toxina Shiga II/genética , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Animales , Niño , Preescolar , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/diagnóstico , Proteínas de Escherichia coli/genética , Femenino , Síndrome Hemolítico-Urémico/diagnóstico , Humanos , Lactante , Italia/epidemiología , Masculino , Tipificación Molecular , Vigilancia de la PoblaciónRESUMEN
BACKGROUND: On 5 June 2012 several enterohemorrhagic Escherichia coli, EHEC, O157:H7 infections were reported to the public health authorities of Limburg. METHODS: We performed a case-control study, a trace back/forward investigation and compared strains isolated from human cases and food samples. A case was defined as anyone with a laboratory-confirmed E. coli O157:H7-infection in North-East Limburg from May 30 2012 till July 15 2012. Family members with bloody diarrhea were also included as cases. E. coli O157 was isolated by culture and the presence of the virulence genes was verified using (q)PCR. Isolates were genotyped and compared by Pulsed Field Gel Electrophoresis (PFGE) and insertion sequence 629-printing (IS629-printing). RESULTS: The outbreak involved 24 cases, of which 17 were laboratory-confirmed. Five cases developed Hemolytic Uremic Syndrome (HUS) and fifteen were hospitalized. Cases reported a significantly higher consumption of "steak tartare", a raw meat product (OR 48.12; 95% CI; 5.62- 416.01). Cases were also more likely to buy meat-products at certain butcheries (OR 11.67; 95% CI; 1.41 - 96.49). PFGE and IS629-printing demonstrated that the vtx1a vtx2a eae ehxA positive EHEC O157:H7 strains isolated from three meat products and all seventeen human stool samples were identical. In a slaughterhouse, identified by the trace-back investigation, a carcass infected with a different EHEC strain was found and confiscated. CONCLUSION: We present a well described and effectively investigated foodborne outbreak associated with meat products. Our main recommendations are the facilitation and acceleration of the outbreak detection and the development of a communication plan to reaches all persons at risk. MESH: Foodborne diseases, Shiga-toxigenic Escherichia coli, Enterohemorrhagic Escherichia coli, Meat products, Case control studies, Electrophoresis, Gel, Pulsed-Field.