On September 9, 2021, the Regional Health Agency (ARS) of Hauts-de-France was informed of a suspicion of collective food poisoning (TIAC) affecting half-board students, educated in several schools in a municipality. of the Lille metropolis.
On September 13, 2021, two cases of haemolytic and uremic syndrome (HUS) were diagnosed in two hospitalized children attending school in this town. Public Health France Hauts-de-France was asked by the Hauts-de-France ARS to provide support for the investigations and management of this TIAC. A total of 35 cases of gastroenteritis, with bloody diarrhea and fever (>38°C) in half of the cases, were identified. Ten cases were hospitalized and two children developed HUS.
The cases identified were half-board students in four school groups (29 cases), a parent of a student and elderly people benefiting from the municipality’s home meal delivery service (5 cases). The case canteens were all supplied by the central municipal kitchen.
The shape of the epidemic curve was in favour of a common and point source of contamination during meals on September 2 or 3, 2021. The case-control survey, carried out in schools, concluded that only the consumption of cucumbers in salad, served with the meal on September 2, was statistically and significantly associated with the occurrence of the disease.
A strain of E. highly pathogenic Shiga toxin-producing (STEC) O157 coli was isolated from the stool cultures of eight cases, including the two children who developed HUS and in the offending cucumber salad. Genomic analysis of the strains confirmed the genetic clustering of clinical and food strains that belonged to the same genomic cluster. The veterinary investigation revealed that a failure in the decontamination process, associated with incomplete peeling of the contaminated cucumbers, contributed to the occurrence of this TIAC.
The cucumbers in question came from Belgium and the Belgian health authorities were informed via the dedicated European alert circuits. No other episodes of clusters of STEC infection related to this TIAC have been reported to the ARS over the period while cucumbers from the same batch had been widely distributed in communities and commercial catering services in the Hauts-de-France region. The food vehicle, incriminated in this TIAC, is part of the plants at risk because of its raw mode of consumption. It is important to remind vulnerable populations and collective catering services that preventing the risk of STEC infection, linked to the consumption of raw vegetables, requires washing, disinfection and peeling.
FoodWorld 