Skip to content

S. Mississippi

At a Glance
Antigenic Formula 1,13,23:b:1,5
Serogroup O:13 (G)
NCBI Pathogen Detection View isolates

Background Information

Salmonella enterica subsp. enterica serovar Mississippi (antigenic formula 1,13,23:​b:1,5) is a serovar of the O:13 (G) serogroup. This serovar was initially identified in 1943 after being isolated from a food handler's stool sample in Mississippi, US. In the US, serovar Mississippi ranked as the 14th most prevalent serovar in human clinical cases in 2016, whereas in Tasmania, it is the second most common, responsible for 37% of all nontyphoidal salmonellosis cases in the state. In Australia, exposure to contaminated drinking water and wildlife contact have been documented as transmission routes for serovar Mississippi infections, while in US, the infections are primarily linked to animal contact. Chui et al. reported a case of left renal abscess and gram-negative sepsis associated with Salmonella Mississippi infection.

Genetic Characteristics

Serovar Mississippi has been found to be polyphyletic with three lineages identified. Similarly, den Bakker et al. and Miller et al. also suggested that serovar Mississippi was likely to be polyphyletic. Cheng et al. phylogenetic analysis of 364 S. Mississippi isolates from Australia, the UK, and US revealed geographic clustering, with U.S. (subclade Ai) and Australian (subclade Aii) isolates forming distinct groups within clade A, while clade B predominated in the UK. Genetic divergence within clades was driven by mobile elements carrying virulence factors: clade A variations arose from prophage differences (i.e., Entero_mEp460, Gifsy-2, Salmon_118970_sal3, and Salmon_vB_SosS_Oslo), whereas clade B diversity stemmed from acquisition of a 47.1-kb integrative conjugative element (ICE). Miller et al. also found that, for serovar Mississippi isolates, genes encoding S-CDT (Salmonella cytolethal distending toxins) are clade associated. Ford et al. analyzed a total of 62 serovar Mississippi isolates from Australia and no antimicrobial resistance genes were detected in these isolates, except for a single human isolate from Tasmania carrying blaTEM-1, which confers ampicillin resistance.

Animal Reservoir

Unknown, but according to the metadata from NCBI PD, serovar Mississippi was isolated from wild animals such as turtles, and birds (Porphyrio hochstetteri).

Geographical Distribution

Cheng et al. found that serovar Mississippi were endemic in Australia, the United Kingdom, and the United States. According to the metadata from NCBI PD, this serovar has been reported in other countries such as Chile and Bermuda.

Human/Animal Outbreaks

Year Location Associated source Number of cases
2022 US Unknown At least 99

Border Rejections

There have been no recent border rejections linked to this serovar.

Recalls

There have been no recent recalls linked to this serovar.

References

  1. https://journals.sagepub.com/doi/abs/10.3181/00379727-54-14395
  2. https://pmc.ncbi.nlm.nih.gov/articles/PMC8550085/
  3. https://journals.asm.org/doi/10.1128/aac.02012-17
  4. https://wwwnc.cdc.gov/eid/article/25/9/18-1811_article
  5. https://www.cambridge.org/core/journals/epidemiology-and-infection/article/salmonella-mississippi-infections-in-tasmania-the-role-of-native-australian-animals-and-untreated-drinking-water/195BDF776A0BCE5D88A798AB59C0D4F1
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC7168582/
  7. https://www.sciencedirect.com/science/article/pii/S2214442022002091
  8. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full#h10
  9. https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-12-425
  10. https://pubmed.ncbi.nlm.nih.gov/27999166/
  11. https://pmc.ncbi.nlm.nih.gov/articles/PMC8550085/
  12. https://pmc.ncbi.nlm.nih.gov/articles/PMC6711244/
  13. https://www.foodsafetynews.com/2022/08/fda-reports-new-outbreak-of-salmonella-infections-source-of-pathogen-unknown/