Salmonella I 4,[5],12:b:-

Background: Salmonella enterica subsp. enterica serovar I 4,[5],12:b:- (antigenic formula 1,4,[5],12:b:-) is a serovar of the O:4 (B) serogroup. This serovar is monophasic which doesn't express phase 2 flagellar antigen. Serovar I 4,[5],12:b:- might be the monophasic variant of serovar Paratyphi B, as they only differ in the H₂ antigen. This serovar has been documented as a fluctuating serovar in broiler flocks and has been identified in poultry slaughterhouses in Spain and Denmark. It is also sporadically isolated from human gastroenteritis cases.

NCBI PD link for serovar I 4,[5],12:b:-: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=I%204:b:-%22)

Genetic characteristics: Serovar I 4,[5],12:b:- has been found to be polyphyletic with three lineages identified and one stand-alone singleton that does not cluster with any other Salmonella I 4,[5],12:b:- isolates. Initial characterization through multilocus sequence typing revealed that serovar I 4,[5],12:b:− strains clustered into multiple eBurst groups. Some of these groups included the biphasic serovars Paratyphi B, Dublin, and Enteritidis. Similarly, Toboldt et al. found that serovar I 4,[5],12:b:− is polyphyletic. Two sequence types (ST88 and ST127) were associated with serovar Paratyphi B (d-tartrate positive), while two single-locus variants of ST1583 were linked to serovar Abony. Additionally, one sequence type (ST1484) was associated with Mygdal, a recently identified and newly defined serovar. Both NARMS and whole genome sequencing analysis didn't identify any predicted antibiotic resistance in the outbreak isolates.

Animal reservoir: Chicken may be the primary reservoir of serovar I 4,[5],12:b:-; however, this serovar has also been isolated from horses in the past.

Geographical distribution: Serovar I 4,[5],12:b:- has been report in Australia, China, Ghana, Europe, and North America including the US and Canada. 

Human outbreaks: 

¹ This outbreak was also associated with Salmonella Javiana, Okatie, and Thompson. The case number here applies exclusively to infections caused by Salmonella I 4,[5],12:b:-.

² This outbreak also involved Salmonella Newport. The case number here applies exclusively to infections caused by Salmonella I 4,[5],12:b:-.

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

Recalls:

¹ The recall was prompted by the multistate outbreak described above. The FDA has compiled a full list of recalled kratom products, but it is currently unavailable.

Relevant links:

1. https://www.pasteur.fr/sites/default/files/veng_0.pdf
2. https://www.sciencedirect.com/science/article/pii/S0378113501003479?via%3Dihub
3. https://www.sciencedirect.com/science/article/pii/S0378113596012904?via%3Dihub
4. https://www.sciencedirect.com/science/article/pii/S1567134810002030?via%3Dihub
5. https://academic.oup.com/jambio/article-abstract/94/5/826/6722108?redirectedFrom=fulltext
6. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
7. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1002776
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3753948/#B4
9. https://www.researchgate.net/publication/241693851_Population_Structure_of_Salmonella_enterica_Serovar_4512b-_Strains_and_Likely_Sources_of_Human_Infection
10. https://archive.cdc.gov/www_cdc_gov/salmonella/kratom-02-18/index.html
11. https://archive.cdc.gov/#/details?url=https://www.cdc.gov/salmonella/coconut-01-18/index.html