Characterization of Clostridium Baratii Type F Strains Responsible for an Outbreak of Botulism Linked to Beef Meat Consumption in France

Christelle Mazuet (1) , Christine Legeay (1) , Jean Sautereau (1) , Christiane Bouchier (2) , Alexis Criscuolo (3) , Philippe Bouvet (1) , Hélène Tréhard (4) , Nathalie Jourdan da Silva (4) , Michel Popoff (1)

1 CNR - Centre National de Référence des Bactéries Anaérobies et Botulisme - National Reference Center Anaerobic Bacteria and Botulism
2 Génomique (Plate-Forme) - Genomics Platform
3 Hub Bioinformatique et Biostatistique - Bioinformatics and Biostatistics HUB
4 INVS - Institut de Veille Sanitaire

Introduction: A second botulism outbreak due to Clostridium baratii occurred in France in August 2015 and included three patients who had their meal in a restaurant the same day. We report the characterization of C. baratii isolates including whole genome sequencing (WGS). Methods: Four C. baratii isolates collected in August 2015 from the outbreak 2 were analysed for toxin production and typing as well as for genetic characterization. WGS was done using using the NEBNext Ultra DNA Library Prep kit for Illumina (New England Biolabs) and sequenced on MiSeq machine (Illumina) in paired-end reads of 250 bases. The phylogenetic tree was generated based on the UPGMA method with genetic distances computed by using the Kimura two-parameter model. Evolutionary analyses were conducted in Bionumerics (V.6.6 Applied Maths). Results: Three C. baratii isolates for patient's stools and one isolate from meat produced botulinum neurotoxin (BoNT) type F and retained a bont/F7 gene in OrfX cluster. All isolates were identical according to the WGS. However, phylogeny of the core genome showed that the four C. baratii strains were distantly related to that of the previous C. baratii outbreak in France in 2014 and from the other C. baratii strains reported in databanks. Discussion: The fact that the strains isolated from the patients and meat samples were genetically identical supports that the meat used for the Bolognese sauce was responsible for this second botulism outbreak in France. These isolates were unrelated to that from the first C. baratii outbreak in France in 2014 indicating a distinct source of contamination. WGS provided robust determination of genetic relatedness and information regarding BoNT typing and toxin gene locus genomic localization.

Domaines: Toxicologie

Christelle Mazuet, Christine Legeay, Jean Sautereau, Christiane Bouchier, Alexis Criscuolo, et al.. Characterization of Clostridium Baratii Type F Strains Responsible for an Outbreak of Botulism Linked to Beef Meat Consumption in France. PLoS Currents, 2017, 9, pp.ecurrents.outbreaks.6ed2fe754b58a5c42d0c33d586ffc606. ⟨10.1371/currents.outbreaks.6ed2fe754b58a5c42d0c33d586ffc606⟩. ⟨pasteur-01820487⟩