Salmonella Muenster

Background: Salmonella enterica subsp. enterica serovar Muenster (antigenic formula 3,{10}{15}{15,34}:e,h:1,5) is a serovar of the O:3,10 (E₁) serogroup. The serovars previously known as Newhaw and Arkansas are now classified as variants of serovar Muenster. Newhaw is designated as Muenster var. 15⁺ (converted by phage ε15), while Arkansas is Muenster var. 15⁺,34⁺ (converted by phages ε15 and ε34). These variants occupy the same serological position as group O:4 (B) strains, which express factor 1 upon conversion but had not been assigned new names. During 1986, Salmonella spp. (primarily serovar Muenster) was detected in 2.9% of raw milk samples from dairy herds in southwestern Ontario, but the prevalence declined to zero within approximately a year. According to the 1996 USDA prevalence study, serovar Muenster ranked as the seventh most frequent serotype, representing 4.7% of all Salmonella spp. isolates in US dairy operations. Serovar Muenster can cause abortion or diarrhea in cows in late gestation.

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

Genetic characteristics: Chang et al. found an Muenster isolate with a 260-kb bla _CTX-M-55-qnrS1-bearing IncHI2 plasmid. Argentinian researchers reported that serovar Muenster had low pathogenic potential in swine. Osman et al. revealed that 2 out of 5 Muenster isolates included in their study exhibited resistance to lincomycin, streptomycin and chloramphenicol. Nguyen et al. collected a total of 47 duck carcass samples in wet markets during October 2019 in Vietnam and isolated seven strains of serovar Muenster belonging to ST 321. Among these seven isolates, three of them harbored C63PI, an iron transport system located in SPI-1. Three plasmid replicons were identified in these Muenster isolates (IncHI2_1, IncHI2A_1, and IncL/M(pMU407)_1_pMU407). All seven isolates exhibited ESBL phenotypes and carried the bla_CTX-M-55 variants (i.e., bla_TEM-1B, bla_CTX-M-55, bla_TEM-206, bla_TEM-214, and bla_TEM-141).

Animal reservoir: Dairy cattle is the reservoir for serovar Muenster. This serovar was also isolated from other animals such as pet bearded dragons, and birds (Tympanuchus cupido, Antigone canadensis).

Geographical distribution: According to the metadata from NCBI PD, serovar Muenster has been reported globally but primarily in US. Among a total of 2,659 serovar Muenster isolates available in NCBI PD (accessed 04/29/2025), there were 2,040 isolates collected in US.  

Human outbreaks: 

Border rejections:

¹ Salmonella Infantis and Muenster were found.

Recalls: 

Relevant links: 

1. https://www.pasteur.fr/sites/default/files/veng_0.pdf
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC1255394/
3. https://www.sciencedirect.com/science/article/pii/S0362028X22090214?via%3Dihub
4. https://www.aphis.usda.gov/sites/default/files/dairy96_is_ecoli_salm.pdf
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC339296/
6. https://pubmed.ncbi.nlm.nih.gov/35464949/
7. https://pubmed.ncbi.nlm.nih.gov/19642916/
8. https://pubmed.ncbi.nlm.nih.gov/23621859/
9. https://www.mdpi.com/1467-3045/45/3/143
10. https://archive.cdc.gov/www_cdc_gov/salmonella/muenster-10-20/index.html
11. https://www.researchgate.net/publication/26722284_Outbreak_of_Salmonella_Enterica_serotype_Muenster_infections_associated_with_goat's_cheese_France_March_2008
12. https://archive.cdc.gov/www_cdc_gov/salmonella/live-poultry-05-16/index.html
13. https://www.sciencedirect.com/science/article/pii/S0362028X23011390/pdf?md5=582b240cc5805df00a53b1edbd704a5d&pid=1-s2.0-S0362028X23011390-main.pdf
14. https://webgate.ec.europa.eu/rasff-window/screen/notification/695422
15. https://webgate.ec.europa.eu/rasff-window/screen/notification/433763
16. https://webgate.ec.europa.eu/rasff-window/screen/notification/420010
17. https://webgate.ec.europa.eu/rasff-window/screen/notification/710185