Background: Salmonella enterica subsp. enterica serovar Mikawasima (antigenic formula 6,7,14:y:e,n,z15) is a serovar of the O:7 (C1) serogroup. Serovar Mikawasima was first isolated from tortoises in 1967 in Turkey. The first isolation of serovar Mikawasima within the EU/EEA was reported in 1976 as part of a large-scale investigation into Salmonella prevalence in Dutch pigs. Between 2007 and 2012, a total of 671 human serovar Mikawasima infections were reported to the European Surveillance System (TESSy) by EU/EEA countries. Case numbers in Europe have shown a consistent rise since 2009. In US, there are no reports of serovar Mikawasima in humans and animals in the last 10 years.
NCBI PD link for serovar Mikawasima: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=Mikawasima%22)
Genetic characteristics: According to Novak et al. (2024), all the outbreak-related isolates (n=75) were resistant to ampicillin and gentamicin. Most isolates (98%) showed resistance to amoxicillin/clavulanic acid, third-generation cephalosporins (36% to ceftriaxone and 47% to ceftazidime) and 40% of the isolates exhibited extended-spectrum β-lactamase production. In addition, whole-genome sequencing (WGS) analysis revealed that three outbreak-related strains (ST2030) have the same resistance gene profile [blaTEM-1B, aac(6')-Iaa, aac(6')-Im, and aph(2'')-Ib)].
Animal reservoir: Pigs and wild boars are the reservoirs for serovar Mikawasima. This serovar was also isolated from turtle.
Geographical distribution: Serovar Mikawasima appears to be frequently found in Europe especially Spain but occasionally in other continents such as Asia and North America.
Human outbreaks:
Year | Location | Associated source | Number of cases |
| 2020-2021 | Croatia | Unknown | 27 |
| 2019 | Europe: multi-country | Unknown | 192 |
| 2018 | Europe: multi-country | Unknown | 50 |
2013 | UK | 75 | |
2012 | Norway | 13 | |
1992 | UK | 9 |
Border rejections: There have been no recent border rejections linked to this serovar.
Recalls:
| Year | Location | Recalled food | Type |
|---|---|---|---|
| 2020 | Norway | Organic Little gem lettuce from Spain | Fruits and vegetables |
Relevant links:
- https://pubmed.ncbi.nlm.nih.gov/5600522/
- https://www.ecdc.europa.eu/en/publications-data/european-surveillance-system-tessy
- https://pubmed.ncbi.nlm.nih.gov/38330414/
- https://www.ecdc.europa.eu/sites/default/files/media/en/publications/Publications/RRA-unusual-increase-salmonella-mikawasima-cases-in-EU-EEA-28-november-2013.pdf
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3298264/
- https://www.ecdc.europa.eu/sites/default/files/documents/SALM_AER_2019_Report_Final.pdf
- https://www.croris.hr/crosbi/publikacija/prilog-skup/729181
- https://www.foodsafetynews.com/2019/11/uk-bears-brunt-of-multi-country-salmonella-outbreak/#google_vignette
- https://www.foodsafetynews.com/2018/09/rare-salmonella-strain-sickens-50-in-five-eu-countries/
- https://pubmed.ncbi.nlm.nih.gov/8270007/
- https://webgate.ec.europa.eu/rasff-window/screen/notification/420202
- http://www.ncbi.nlm.nih.gov/pubmed/13889310