S. I 4,[5],12:b:-¶

At a Glance


Antigenic Formula	`1,4,[5],12:b:-`
Serogroup	O:4 (B)
NCBI Pathogen Detection	View isolates

Background Information¶

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.

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/Animal Outbreaks¶

Year	Location	Associated source	Number of cases
2018	US: multistate	Kratom powder¹	61
2018	US: multistate, Canada	Shredded Frozen Coconut²	26

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¶

Year	Location	Recalled food	Type
2018	US: multistate	Kratom¹	Other food product / mixed

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.