Background: Salmonella enterica subsp. enterica serovar Rissen (antigenic formula 6,7,14:f,g:-) is a serovar of the O:7 (C1) serogroup. This serovar was first isolated from HOST in LOCATION in YEAR. Serovar Rissen is the 4th most common nontyphoidal Salmonella serovar isolated from human infections in Thailand and is also among the top 20 most frequently reported Salmonella serovars in the United States

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

Genetic characteristics: Serovar Rissen ST469 was found worldwide such as Thailand, China, Italy and this sequence type was the most common ST for serovar Rissen. ST8877 was found in Sudan which was isolated from a cracked table egg.

Pornsukarom et al. reported that all Thai Rissen isolates in this study were multidrug-resistant and more than 90% were resistant to ampicillin, sulfisoxazole, tetracycline and streptomycin. Half of Rissen isolates in the USA were pan-sensitive and some of US isolates were resistant to only tetracycline. Wang et al. identified Rissen human isolates (anal swabs or feces) had the common resistance profile as ampicillin, trimethoprim-sulfamethoxazole, and tetracycline; respectively conferring to resistance genes blaTEM, tetA, and sul3.

Animal reservoir: Swine is the major animal reservoir of serovar Rissen, including pork production chain.

Geographical distribution: Serotype Rissen has been reported especially in Asian countries such as Thailand, China, and Vietnam, but also found in Italy, France, Spain. 

Human outbreaks: Two outbreaks linked to Salmonella Rissen have been associated with food. Some examples are shown below.

Year

Location

Associated source

Number of cases

2020FranceFuet from Spain18

2008-2009

US: multistate

White pepper

87

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

Year

Exporting country

Importing country

Associated source

Product category

2024Denmark

Finland

Rapeseed expellers

Feed materials

2022Spain

Belgium

Turkey processed animal protein

Feed materials

2022Ukraine

Germany

Sunflower cake

Feed materials

2020Spain

Switzerland

Chorizo sausage

Meat and meat products (other than poultry)

2020Belgium

Austria

Dog feed

Pet food

Recalls: 

YearLocationRecalled foodType
2020FranceFuet1Food
2019US: multistatePig ears2Pet treats

1 This recall was caused by France to withdraw all fuet with all dates and bearing the mark ES-10.12147/B-CE carried out in various stores across France. 

2 This recall was caused by an multistate outbreak of many Salmonella serovars including Rissen linked to pig ears feeding to dogs.  

Relevant links:

1. https://www.pasteur.fr/sites/default/files/veng_0.pdf

2. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.702909/full

3. https://www.mdpi.com/2079-6382/9/10/660

4. https://www.veterinaryworld.org/Vol.16/May-2023/6.html

5. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.968695/full

6. https://www.pagepressjournals.org/index.php/ijfs/article/view/9362

7. https://www.nature.com/articles/s41598-024-62141-9

8. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.705044/full