Salmonella Schwarzengrund

Background: Salmonella enterica subsp. enterica serovar Schwarzengrund (antigenic formula 1,4,12,27:d:1,7) is a serovar of the O:4 (B) serogroup.  S. Schwarzengrund is among the most common serovars in non-clinical non-human sources in the US. This serovar was first reported in North America in 1952 when it was isolated from turkey poults. A case report from Japan indicates that pyogenic sacroiliitis, a rare type of extraintestinal infection, has been reported for this serovar. 

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

Genetic Characteristics: Serovar Schwarzengrund has been found to be polyphyletic with four lineages identified and one stand-alone singleton that does not cluster with any other Salmonella Schwarzengrund isolates. A study of antimicrobial resistance in global Salmonella isolates found that serovar Schwarzengrund was positively correlated with fluoroquinolone resistance. In addition, fluoroquinolone resistant strains have been linked to imported food in the US. Multidrug resistant (MDR) strains (e.g., resistant to dihydrostreptomycin, kanamycin, oxytetracycline, bicozamycin, trimethoprim, and sulfadimethoxine) have been linked to broilers in Japan. MDR S. Schwarzengrund was found to be transmitted from chickens to people in some countries in Asia. A serovar Schwarzengrund isolate was found to carry some markers of the plasmid to Emergent Salmonella Infantis (pESI). 

Animal reservoir: Poultry is the main reservoir of S. Schwarzengrund. This serovar has also been found in dogs. 

Geographical distribution: S. Schwarzengrund is widely distributed. This serovar has been reported to be prevalent in Asia and it has been found in Europe and the US as well.

Human Outbreaks: Outbreaks associated with S. Schwarzengrund have been reported in the US; in addition, in Denmark cases have been linked to Thai food products.

Border Rejections: 

¹Serovars Poona and Matadi were also found in this product

²Serovar Javiana was also found in this product

Recalls: 

Relevant links:

1. https://www.science.org/doi/10.1126/science.116.3024.669.a
2. https://doi.org/10.1186/s12245-023-00496-y
3. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
4. http://wwwnc.cdc.gov/eid/article/20/1/13-1179_article.htm
5. http://jac.oxfordjournals.org/content/early/2011/10/18/jac.dkr414.full.pdf
6. https://www.jstage.jst.go.jp/article/yoken/62/3/62_JJID.2009.198/_article
7. http://wwwnc.cdc.gov/eid/article/13/5/06-1489_article.htm
8. https://doi.org/10.1111/zph.13174
9. https://doi.org/10.1038/s41467-025-59758-3
10. https://doi.org/10.1016/j.fm.2022.104112
11. https://www.ecdc.europa.eu/sites/default/files/documents/SALM_AER_2022_Report.pdf
12. https://archive.cdc.gov/#/details?url=https://www.cdc.gov/salmonella/schwarzengrund-03-19/index.html
13. https://doi.org/10.1016/j.ijbiomac.2017.09.005
14. https://wwwnc.cdc.gov/eid/article/20/1/13-1179_article

15. https://doi.org/10.1542/peds.2009-3273

16. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5719a4.htm
17. https://www.nejm.org/doi/full/10.1056/NEJM200105243442102
18. https://webgate.ec.europa.eu/rasff-window/screen/notification/753859
19. https://webgate.ec.europa.eu/rasff-window/screen/notification/523752
20. https://webgate.ec.europa.eu/rasff-window/screen/notification/452358
21. https://www.fsis.usda.gov/recalls-alerts/butterball-llc-recalls-turkey-products-due-possible-salmonella-schwarzengrund