Salmonella Agona

Background: Salmonella enterica subsp. enterica serovar Agona (antigenic formula 1,4,[5],12:f,g,s:[1,2]) is a serovar of the O:4 (B) serogroup. This serovar was first isolated from cattle in Ghana in 1952. Serovar Agona is the 10th most common nontyphoidal Salmonella serotype isolated from human infections in China and is also among the top 20 most frequently reported Salmonella serotypes in the United States.

NCBI PD link for serovar Agona: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=Agona%22)

Genetic characteristics: Serovar Agona has been found to be polyphyletic with one lineage identified and one stand-alone singleton that does not cluster with any other Salmonella Agona isolates. Comparative genomics of 73 of the sequenced strains identified three lineages of serovar Agona that emerged approx. 90 years ago. Serovar Agona has an accessory genome of approx. 1.3 Mb; this accessory genome includes (i) multiple prophages (P2-like, Fels-like, Lambda-like), (ii) antibiotic resistance plasmids (e.g., IncI1 plasmids), (iii) genomic islands, (iv) transposons, and (v) chromosomal integrons. Phylogenetic and pan-genomic analyses that included one of the sequenced serovar Agona strains and other Salmonella serovars concluded that serovar Agona belongs to clade A, according to den Bakker et al. (2011) classification and it contains 133 gene families unique to this serovar. Bartsch reported the MDR isolate, 18-SA00377, isolated in Germany in 2018, harbored pSE18-SA00377-1 plasmid (295,499 bp) carrying 16 ARGs. Song et al. analyzed 209 Agona isolates obtained from food-producing animals during 2010–2020 in South Korea  and found that resistance to ampicillin, chloramphenicol, streptomycin, tetracycline, and trimethoprim/sulfamethoxazole was the most frequently observed MDR pattern (60.6%, 86/142) in isolates from chickens and ducks. Among the three sequence types (STs) detected-ST13, ST11, and ST292-ST13 was predominant. In a UK study, Waters et al. identified an increase in SNP variation in 207 Agona isolates associated with acute and persistent infections potentially reflecting a population expansion after acute S. Agona infection. 

Animal reservoir: Multiple animal species, including turkey, swine and cattle are reservoirs of serovar Agona.

Geographical distribution: Serovar Agona has been reported worldwide such as the US, the UK, and China.

Human outbreaks: Numerous outbreaks linked to Salmonella Agona have been associated with a variety of foods, including cereal, meat and fruits. Some examples are shown below. 

Border rejections: Multiple border rejections associated with serovar Agona have been reported. Here we selected two as examples.

Recalls: Multiple recalls associated with serovar Agona have been reported. Here we selected two as examples.

¹ This recall was caused by an outbreak of Salmonella enterica serovar Agona associated with infant formula products manufactured by the Lactalis Nutrition Santé group in France.

² This recall was caused by an multistate outbreak of Salmonella serovar Agona infections linked to toasted oats cereal manufactured by Malt-O-Meal. 

Relevant links:

1. https://pubmed.ncbi.nlm.nih.gov/13902866/
2. https://www.liebertpub.com/doi/full/10.1089/fpd.2010.0827?casa_token=r5_H4WYgMn0AAAAA%3A5MU6aDnk2JmPoDATaXDvLO7TXqqWkEc57PaWFHA6ef0LkN2mJecTbfXy73ZKQ06d-5LnTu3a6w
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC3739514/
4. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
5. https://journals.asm.org/doi/10.1128/aem.00591-19#:~:text=Agona%20is%20ranked%20among%20the,and%20different%20animal%2Dbased%20foods.
6. https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1003471
7. https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-12-425
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3175032/
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC10686068/
10. https://www.liebertpub.com/doi/10.1089/fpd.2023.0117?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
11. https://pmc.ncbi.nlm.nih.gov/articles/PMC11556752/
12. https://www.foodsafetynews.com/2022/12/cucumbers-linked-to-multi-country-salmonella-outbreak/
13. https://archive.cdc.gov/www_cdc_gov/salmonella/2011/papayas-8-29-2011.html
14. https://archive.cdc.gov/www_cdc_gov/salmonella/2008/rice-wheat-puff-cereal-5-13-2008.html
15. https://www.researchgate.net/publication/23228196_A_multi-country_outbreak_of_Salmonella_Agona_February_-_August_2008
16. https://pubmed.ncbi.nlm.nih.gov/17259878/
17. https://pmc.ncbi.nlm.nih.gov/articles/PMC3371796/
18. https://www.cdc.gov/mmwr/preview/mmwrhtml/00053368.htm
19. https://webgate.ec.europa.eu/rasff-window/screen/notification/722223
20. https://webgate.ec.europa.eu/rasff-window/screen/notification/559290
21. https://www.who.int/emergencies/disease-outbreak-news/item/22-december-2017-salmonella-agona-infections-france-en