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Background: Salmonella enterica subsp. enterica serovar Mbandaka (antigenic formula 6,7,14:z₁₀:e,n,z₁₅) is a serovar of the O:7 (C₁) serogroup. This serovar was first isolated in 1948 from a human salmonellosis case in the Belgian Congo. Serovar Mbandaka was ranked among the top 10 serovars responsible for human salmonellosis cases in Europe. This serovar was also among the 20 most prevalent serovars associated with human cases in other countries, along with Israel, North America, Africa, and New Zealand. In a Chinese pig farm, serovar Mbandaka (12.6%) ranked as the fourth most prevalent serovar identified. In nine broiler slaughterhouses in Brazil, serovar Mbandaka (12.7%) was the third most frequent serovars isolated. This serovar was reported to cause travel-associated  associated sacroiliac osteomyelitis in a healthy adolescent. 

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

Genetic characteristics: Salmonella Mbandaka can be classified into two major groups. However, clustering of these groups and their subgroups were not associated with any patterns based on the host or geographical origin. A study found that all isolates contained a uniform virulence gene repertoire. This serovar is multi-drug resistant.  Serovar Mbandaka has been found to be polyphyletic with one lineage identified and one stand-alone singleton that does not cluster with any other Salmonella Mbandaka isolates. A Canadian study using CRISPR-SeroSeq on Ontario poultry farms found that spacer reads could not distinguish between serovars Montevideo and Mbandaka. Antony et al. included more than 400 serovar Mbandaka isolates in their study and found two major groups with no pattern identified based on host or geographical origin. Additionally, they reported that a uniform virulence gene profile in all serovar Mbandaka isolates. Their phenotypic analysis revealed a similar trend in adaptation to a low pH environment and cell invasion behavior using a representative set of isolates. Among 403 Mbandaka genomes, resistance to tetracycline (16.87%) was the most common, followed by aminoglycosides (13.89%), sulfonamide (8.4%), QAC (6.9%), trimethoprim (5.7%), and quinolone (3.47%). The tetracycline resistance gene tet(B) was the most common (10.66%), followed by the aminoglycoside resistance genes aph(6)-Id (8.93%) and aph(3'')-Ib (8.68%). Hayward et al. revealed that Salmonella pathogenicity island 23 was found in several serovars, including Salmonella Agona, Dublin and Gallinarum, but it is absent in Salmonella Mbandaka. In Poland, serovar Mbandaka carrying the bla_CTX-M-8 gene located on IncI1 plasmid was isolated from a broiler farm. Some Mbandaka isolates exhibited resistance to multiple drugs. For instance, in a Brazilian study, all 6 Mbandaka isolates carried aac(6′)-Iaa (amikacin/tobramycin resistance), while aadA1 (spectinomycin), sul1 (sulfonamides), dfrA variants (trimethoprim), and tetB (tetracycline) were detected in 4–5 of 6 isolates.

Animal reservoir: Chicken is the main reservoir for serovar Mbandaka. This serovar was also isolated from other animals (pigs, cattle, fish, wild birds, and canine). 

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Human outbreaks: Numerous outbreaks in different countries have been linked to serovar Mbandaka, imported spices have been associated with several of these outbreaks. Below are some examples. 

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¹ This recall was resulted by a multistate outbreak described above. Kellogg company voluntarily recalled their 15.3 oz. and 23 oz. packages of honey smacks cereal.

Relevant links:

1. https://www.aaem.pl/Fifteen-years-of-successful-spread-of-Salmonella-enterica-serovar-Mbandaka-clone-ST413-in-Poland-and-its-public-health-consequences,72405,0,2.html
2. https://www.efsa.europa.eu/en/efsajournal/pub/3129
3. https://orbit.dtu.dk/files/5208629/PhD_Thesis_RSHE_281209%20(2)%2017x24.pdf
4. https://www.liebertpub.com/doi/10.1089/fpd.2021.0018?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed
5. https://www.veterinariaitaliana.izs.it/index.php/VetIt/article/view/2434/1189
6. https://onlinelibrary.wiley.com/doi/10.1155/2013/543147
7. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full#h10
8. https://journals.asm.org/doi/10.1128/aem.01923-22?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC7653644/
10. https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-14-365
11. https://pmc.ncbi.nlm.nih.gov/articles/PMC11435008/
12. https://www.mdpi.com/2076-2607/12/2/312
13. https://pubmed.ncbi.nlm.nih.gov/39807938/
14. https://www.cdc.gov/salmonella/outbreaks/backyardpoultry-05-24/?CDC_AAref_Val=https://www.cdc.gov/salmonella/backyardpoultry-05-24/index.html
15. https://www.ecdc.europa.eu/en/publications-data/rapid-outbreak-assessment-multi-country-outbreak-salmonella-mbandaka-st413-linked#:~:text=European%20Centre%20for%20Disease%20Prevention,first%20update%20%2D%2021%20March%202024.
16. https://outbreakdatabase.com/outbreaks/2021-outbreak-of-salmonella-mbandaka-infections-at-a-college-maine
17. https://archive.cdc.gov/#/details?url=https://www.cdc.gov/salmonella/mbandaka-06-18/index.html
18. https://archive.cdc.gov/www_cdc_gov/salmonella/montevideo-tahini-05-13/index.html#:~:text=Investigation%20of%20the%20Outbreak,-During%20routine%20product&text=tahini%20sesame%20paste.-,Additional%20testing%20by%20the%20FDA%20isolated%20Salmonella%20Mbandaka%20from%20imported,recalled%20its%20tahini%20sesame%20paste.
19. https://www.cdc.gov/mmwr/volumes/70/wr/mm7033a1.htm
20. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6310a4.htm
21. https://webgate.ec.europa.eu/rasff-window/screen/notification/728058
22. https://webgate.ec.europa.eu/rasff-window/screen/notification/672949
23. https://webgate.ec.europa.eu/rasff-window/screen/notification/604602
24. https://webgate.ec.europa.eu/rasff-window/screen/notification/482582
25. https://webgate.ec.europa.eu/rasff-window/screen/notification/711679
26. https://webgate.ec.europa.eu/rasff-window/screen/notification/693421
27. https://webgate.ec.europa.eu/rasff-window/screen/notification/613060
28. https://webgate.ec.europa.eu/rasff-window/screen/notification/593511
29. https://webgate.ec.europa.eu/rasff-window/screen/notification/559826
30. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/kellogg-company-voluntarily-recalls-honey-smacks-cereal-due-possible-health-risk
31. https://pubmed.ncbi.nlm.nih.gov/36853053/
32. https://pubmed.ncbi.nlm.nih.gov/36586112/
33. https://pubmed.ncbi.nlm.nih.gov/35722838/
34. https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-14-365
35. https://www.liebertpub.com/doi/10.1089/fpd.2021.0018?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed
36. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7653644/
37. https://doi.org/10.1111/zph.13174