Identification of a new variant with a chromosomally encoded enterotoxin gene in a suspected persistent food poisoning outbreak in Eritrea.

is a causative agent of various human and animal enteric diseases including food poisoning. In this study, we describe an interesting case of a persistent food poisoning outbreak among Finnish peacekeepers in Eritrea, possibly caused by carrying a new variant of the chromosomally encoded enterotoxin gene. strains causing food poisoning carry the enterotoxin gene, , in its chromosome (c-) or on a plasmid (p-). PCR assays are widely used for toxinotype strains. The integration sites for the gene are highly conserved, and PCR assays targeting the gene and the adjacent IS elements (the IS in c- and the IS-like or IS in p- strains) are used to further determine the genetic location of the gene. We sequenced nine enteropathogenic strains related to a persistent food poisoning outbreak among Finnish peacekeepers in Eritrea. Six of these strains produced non-typeable results in the standard PCR assay due to divergence in the enterotoxin integration site. The gene order of the new variant of the chromosomal insertion site with an additional IS1470 element impairing genotyping PCR assay for the location of is described. In addition, variant c- strains carried 58-81 copies of IS1470 in their genomes, compared to 9-23 copies found in previously described c- strains. Thus, the present study represents an untraditional type of food poisoning caused by variant c- strains, and the sequenced strains bring geographic variation to the existing strain collection of sequenced