Background information: Salmonella enterica subsp. enterica serovar Ohio (antigenic formula 6,7,14:b:1,w) is a serovar of the O:7 (C1) serogroup. Serovar Ohio was first described in rodents in Malaysia. This serovar has been previously reported to cause septic arthritis and bone abscess in an immunocompetent patient. In Mexico, serovar Ohio was the most prevalent Salmonella serovar associated with 300 children diagnosed as positive for diarrhoea. This serovar was also isolated from tropical seafood in India. 

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

Genetic characteristics: Serovar Ohio has been found to be monophyletic. Szmolka et al. found serovar Ohio in 4.3% (4 out of 92) of rats collected from various locations in Hungary. Their analysis revealed that 76.4% (117 out of 153) of virulence and antimicrobial resistance genes were shared across Salmonella Ohio, Infantis, Enteritidis, and Typhimurium, with no unique genes specific to serovar Ohio. Additionally, none of serovar Ohio isolates carried virulence or resistance plasmids. A cgMLST analysis showed that serovar Ohio strains from rats in Hungary were closely related to poultry-associated strains in Hungary and grouped with global serovar Ohio isolates from aquatic sources. Agustín et al. studied Salmonella from a pig slaughterhouse in Spain in 1993 and 2001. They found serovar Ohio exhibited multidrug resistance (MDR), with 81% of strains resistant to at least 10 antibiotics (i.e., resistance pattern: ACSSuT‐CB‐MZ‐K‐N‐SxT). Four strains were resistant to 11 antibiotics, and one strain showed resistance to 13 antibiotics.

Animal reservoir: Chicken and pigs may be potential reservoirs for serovar Ohio. This serovar was also isolated from other animals such as horses and wild ducks (Anas platyrhynchos).

Geographical distribution: Serovar Ohio has been reported worldwide, but primarily in the UK and US (Out of 1,386 serovar Ohio isolates, 998 (72.0%) were from US, according to NCBI PD (accessed May 12, 2025)).

Human outbreaks: 

Year

Location

Associated source

Number of cases

2005BelgiumPork60
2004BelgiumUnknown29
1998SpainWaterborne59

Border rejections: 

Year

Exporting country

Importing country

Associated source

Product category

2025ThailandGermanyDog chews1Feed materials
2020DenmarkBelgiumFish mealFeed materials

1 Consignment was released. 

Recalls: 

YearLocationRecalled foodType
2024Finland, DenmarkFrozen pork cheek from Poland via Estonia1Meat and meat products (other than poultry)
2024ItalyFrozen shelled clams from TurkeyFish and fish products
2023Czech RepublicFrozen dumplings with chicken filing from Lithuania2Other food product / mixed

1 Salmonella Ohio, Typhimurium and Derby were found.

2 Salmonella Ohio and Infantis were found. 

Relevant links:

  1. https://pubmed.ncbi.nlm.nih.gov/6523172/
  2. https://pmc.ncbi.nlm.nih.gov/articles/PMC3416725/
  3. https://pubmed.ncbi.nlm.nih.gov/18162140/
  4. https://www.liebertpub.com/doi/epdf/10.1089/fpd.2008.0252
  5. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC11354295/
  7. https://academic.oup.com/lambio/article/41/1/39/6703014?login=true
  8. https://pubmed.ncbi.nlm.nih.gov/19043089/
  9. https://www.sciencedirect.com/science/article/pii/S0362028X22109610
  10. https://pubmed.ncbi.nlm.nih.gov/9666586/
  11. https://webgate.ec.europa.eu/rasff-window/screen/notification/750003
  12. https://webgate.ec.europa.eu/rasff-window/screen/notification/416258
  13. https://webgate.ec.europa.eu/rasff-window/screen/notification/717474
  14. https://webgate.ec.europa.eu/rasff-window/screen/notification/695678
  15. https://webgate.ec.europa.eu/rasff-window/screen/notification/636997
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