Outbreak of unusual H2S-negative monophasic Salmonella Typhimurium strain likely associated with small tomatoes, Sweden, August to October 2019

Euro Surveill. 2019 Nov;24(47):1900643. doi: 10.2807/1560-7917.ES.2019.24.47.1900643.

Abstract

Sweden is investigating an outbreak of monophasic Salmonella Typhimurium. Eighty-two nationally-distributed cases have been confirmed, with date of symptom onset between 28 August and 29 October. Cases were 51 years of age on average (range: 0-89) and the majority of cases were female (62%). A case-control study was conducted and suggested small tomatoes as source of the outbreak (adjusted odds ratio (OR): 10.8, 95% confidence interval (CI): 4.15-112.68, p value < 0.001), and a trace-back investigation led to a single, non-Swedish producer in Europe. Both the Salmonella strain and the source of the outbreak are rarely encountered in Europe. Results from investigation at the producer are pending.

Keywords: Salmonella infections; Sweden; WGS; disease outbreaks; epidemiology; whole genome sequencing.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Disease Outbreaks / statistics & numerical data*
  • Feces / microbiology*
  • Female
  • Food Contamination / statistics & numerical data*
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Multilocus Sequence Typing
  • Salmonella Food Poisoning / epidemiology*
  • Salmonella Food Poisoning / microbiology
  • Salmonella Infections / diagnosis*
  • Salmonella Infections / epidemiology
  • Salmonella typhimurium / classification
  • Salmonella typhimurium / genetics
  • Salmonella typhimurium / isolation & purification*
  • Solanum lycopersicum / microbiology*
  • Sweden / epidemiology
  • Whole Genome Sequencing