A severe foodborne outbreak of diarrhoea linked to a canteen in Italy caused by enteroinvasive Escherichia coli, an uncommon agent

Abstract

We describe a foodborne outbreak in Italy caused by enteroinvasive Escherichia coli (EIEC), an enteric pathogen uncommon in industrialized countries. On 14 April 2012 a number of employees of the city of Milan Fire Brigade (FB) were admitted to hospital with severe diarrhoea after attending their canteen. Thirty-two patients were hospitalized and a total of 109 cases were identified. A case-control study conducted on 83 cases and 32 controls attending the canteen without having symptoms identified cooked vegetables to be significantly associated with the disease. Stool samples collected from 62 subjects were screened for enteric pathogens using PCR-based commercial kits: 17 cases and two asymptomatic kitchen-workers were positive for the Shigella marker gene ipaH; an ipaH-positive EIEC strain O96:H19 was isolated from six cases. EIEC may cause serious dysentery-like outbreaks even in Western European countries. Microbiologists should be aware of microbiological procedures to detect EIEC, to be applied especially when no common enteric pathogens are identified.

Fig. 1.

Distribution of cases (n = 109) by date of symptom onset during an outbreak of gastroenteritis, Milan, Italy, April 2012.

Fig. 2

[colour online]. Invasive pattern of the Escherichia coli O96:H19 epidemic strain in the HEp-2 cells invasion assay (400x, May–Grunwald Giemsa staining), outbreak of gastroenteritis, Milan, Italy, April 2012.