We assessed microbial safety and quality of raw fish sold in Singapore during 2015-2016 to complement epidemiologic findings for an outbreak of infection with group B Streptococcus serotype III sequence type (ST) 283 associated with raw fish consumption. Fish-associated group B Streptococcus ST283 strains included strains nearly identical (0-2 single-nucleotide polymorphisms) with the human outbreak strain, as well as strains in another distinct ST283 clade (57-71 single-nucleotide polymorphisms). Our investigations highlight the risk for contamination of freshwater fish (which are handled and distributed separately from saltwater fish sold as sashimi) and the need for improved hygienic handling of all fish for raw consumption. These results have led to updated policy and guidelines regarding the sale of ready-to-eat raw fish dishes in Singapore.
Keywords: GBS; Singapore; bacteria; clonal complex; consumption; food safety; group B Streptococcus; handling; humans infections; outbreak; raw fish; sequence type; streptococci.