Surveillance for human Salmonella infections plays a critical role in understanding and controlling foodborne illness due to Salmonella. The National Salmonella Reference Laboratory performs serotyping of all Salmonella isolates in Israel. During the last five years (2010-2014) we detected several suspected clusters. All clusters were tested for antimicrobial resistance patterns and genotype relatedness (DNA "fingerprinting"). Six significant clusters were detected, each caused by a different serovar. One of the serovars, S. Muenchen, emerged in 2011 and became the 3rd most prevalent serovar in Israel. Currently, there are three ongoing clusters: S. Coeln, S. Eastbourne and a suspected autochthonous S. Typhi cluster.
S. Coeln is a very rare serovar and scarcely associated with human cases. Currently no S. Coeln clusters are occurring in other developed countries. However, in Europe two clusters have been associated with S. Coeln, one in France (1998) from minced beef and a recent one in Norway (2013) from baby leaf mix. The last S. Eastbourne cluster occurred in Canada (1974) from cocoa beans in a chocolate factory. S. Typhi is the causative agent of typhoid fever, common in under-developed countries, causes a serious, often fatal disease. Most S. Typhi cases are imported. These suspected clusters are currently under molecular and phenotypic characterization in our lab. Epidemiological investigation is essential to reveal the source of the clusters and for the assessment of preventive measures.
