Rapid risk assessment: Multi-country outbreak of Listeria monocytogenes PCR serogroup IVb, MLST ST6

A multi-country outbreak of Listeria monocytogenes PCR serogroup IVb, MLST ST6 has been ongoing in the EU/EEA since at least 2015. Twenty-six cases from Austria, Denmark, Finland, Sweden and the United Kingdom have been classified as a confirmed microbiological cluster on the basis of whole genome sequencing (WGS) analysis, including core genome multi-locus sequence typing (cgMLST) and single nucleotide polymorphism (SNP)-based analysis, depending on the country. Four cases have died (case fatality 15.4%).