S. Ohio¶

At a Glance


Antigenic Formula	`6,7,14:b:1,w`
Serogroup	O:7 (C1)
NCBI Pathogen Detection	View isolates

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 themost prevalent Salmonella serovar associated with 300 children diagnosed as positive for diarrhoea. This serovar was also isolated from tropical seafood in India.

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/Animal Outbreaks¶

Year	Location	Associated source	Number of cases
2005	Belgium	Pork	60
2004	Belgium	Unknown	29
1998	Spain	Waterborne	59

Border Rejections¶

Year	Exporting country	Importing country	Associated source	Product category
2025	Thailand	Germany	Dog chews¹	Feed materials
2020	Denmark	Belgium	Fish meal	Feed materials

¹ Consignment was released.

Recalls¶

Year	Location	Recalled food	Type
2024	Finland, Denmark	Frozen pork cheek from Poland via Estonia¹	Meat and meat products (other than poultry)
2024	Italy	Frozen shelled clams from Turkey	Fish and fish products
2023	Czech Republic	Frozen dumplings with chicken filing from Lithuania²	Other food product / mixed

¹ Salmonella Ohio, Typhimurium and Derby were found.

² Salmonella Ohio and Infantis were found.