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S. Liverpool

At a Glance
Antigenic Formula 1,3,19:d:e,n,z15
Serogroup O:1,3,19 (E4)
NCBI Pathogen Detection View isolates

Background Information

Salmonella enterica subsp. enterica serovar Liverpool (antigenic formula 1,3,19:d:e,n,z15) is a serovar of the O:1,3,19 (E4) serogroup. In the 2021 Salmonella outbreak linked to BrightFarms packaged salad greens, one serovar Liverpool isolate with no illnesses linked was recovered from two indoor growing ponds within the same growing house.

Genetic Characteristics

Serovar Liverpool has been found to be polyphyletic with one lineage identified and one stand-alone singleton that does not cluster with any other Salmonella Liverpool isolates. In an Algerian study, serovar Liverpool isolates they identified belong to sequence types ST1959. Due to the limited genetic characteristics available for this serovar, here, we also incorporated relevant phenotypic characteristics. Estrada and Harris found that serovar Liverpool strain A (persistent) in their study produced a robust biofilm. Amongst all the isolates Obe et al. tested with MIC QAC of 6.25 ppm before exposure, they found that compared to Kentucky and Enteritidis isolates (2-fold), serovar Liverpool isolate had the highest increment (3-fold) in MIC.

Animal Reservoir

Unknown, cattleand poultry may be potential reservoirs for serovar Liverpool.

Geographical Distribution

Serovar Liverpool has been reported occasionally worldwide, but according to NCBI PD (accessed April 15, 2025), the majority of serovar Liverpool isolates originate from US (591 out of 739).

Human/Animal Outbreaks

Year Location Associated source Number of cases
2024 US Unknown1 3

1 Investigation is still ongoing.

Border Rejections

Year Exporting country Importing country Associated source Product category
2024 Denmark Norway Fish meal1 Feed materials
2023 Spain Italy Processed animal proteins (SOA cat.3) Feed materials
2022 China Sweden Crayfish (Procambarus clarckii) Crustaceans and products thereof
2021 Uganda Germany Sesame seeds Nuts, nut products and seeds

1 Salmonella Liverpool and Salmonella Agona were both found.

Recalls

Year Location Recalled food Type
2024 Lithuania Frozen chicken breast from Ukraine via Denmark1 Poultry meat and poultry meat products
2016 US Raw, in-shell pistachios2 Nuts, nut products and seeds
2012 US Dog food3 Pet food

1 Salmonella Senftenberg and Salmonella Liverpool were found.

2 Salmonella Senftenberg and Salmonella Liverpool were found. Trader Joe’s branded pistachios were recalled.

3 Diamond Pet Foods issued a recall of Diamond Naturals Small Breed Adult Lamb and Rice Dry Dog Food.

References

  1. https://pubmed.ncbi.nlm.nih.gov/37003534/
  2. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full#h10
  3. https://pubmed.ncbi.nlm.nih.gov/38502796/
  4. https://pubmed.ncbi.nlm.nih.gov/38493873/
  5. https://www.sciencedirect.com/science/article/pii/S1056617121000581
  6. https://pubmed.ncbi.nlm.nih.gov/17257247/
  7. https://www.sciencedirect.com/science/article/pii/S0032579120303540
  8. https://www.foodsafetynews.com/2024/10/new-outbreak-of-salmonella-infections-detected-other-investigations-continue/
  9. https://webgate.ec.europa.eu/rasff-window/screen/notification/683485
  10. https://webgate.ec.europa.eu/rasff-window/screen/notification/636000
  11. https://webgate.ec.europa.eu/rasff-window/screen/notification/565571
  12. https://webgate.ec.europa.eu/rasff-window/screen/notification/461211
  13. https://webgate.ec.europa.eu/rasff-window/screen/notification/718210
  14. https://www.foodsafetynews.com/2016/10/fda-warnings-seafood-issues-and-salmonella-in-pistachios/
  15. https://www.cidrap.umn.edu/e-coli/news-scan-salmonellosis-live-chicks-response-2011-euro-e-coli-crisis-salmonella-dog-food