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Background: Salmonella enterica subsp. enterica serovar Worthington (antigenic formula 1,13,23:z:l,w) is a serovar of the O:13 (G) serogroup. Serovar Worthington were was first isolated in 1937 from a young turkey and a chick by Dr. Pomeroy. The name of Worthington came from Worthingtonserovar was named after Worthington, Minnesota, where a the location of the hatchery that the poult of this isolate was purchased.

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oldest verified isolation was in 1929 in Denmark. It was in the top 15 most commonly reported Salmonella enterica serovars related to animal contact outbreaks in the United States during 2009–2014.

This serovar was also isolated from turkey-processing plants in the USA in the 1960's. and pig farm environment in Brazil. Although there has been a limited number of research on Salmonella Sandiego, human infections caused by Salmonella Sandiego have been reported, such as a post-traumatic chronic subdural haematoma in an alcoholic heavy drinker patient, and a prevertebral neck abscess in a type 2 diabetes mellitus patient.

raised the birds carrying the original isolates. Serovar Worthington was the 2^nd most common nontyphoidal Salmonella serovar isolated from human infections in India during 2001-2005.  

The most common source of serovar Worthington is turkey, and its production environment. This serovar has been reported in milk powder, vegetables, and seafood. However, serovar Worthington has been frequently reported to cause infection especially in neonatal cases and pediatric wards. Serovar Worthington tends to cause infection in vulnerable groups such as newborns or elderly. Although the symptoms caused by serovar Worthington infection are likely non-typhoidal infection symptoms such as diarrhea or vomiting, in some cases, it can develop to meningitis leading to death. In 1955, there was a report on serovar Worthington suspected causing gastroenteritis including vomiting from artificial feeding in several newborn babies in a small maternity ward in an Indonesian hospital. Another outbreak involving newborn babies occurred in a hospital in Hong Kong in August 1974 leading 13 cases, including 1 death due to meningitis; at the time, the outbreak source was not identified. Five weeks later, five newborns were infected with the same serovar, and in this instance it was found that the outbreak was caused by contamination in the tubing system of a suction apparatus, which was used for baby's oropharyngeal suction. Another outbreak in Pakistan in early 1990s was also linked to contamination of newborn oropharyngeal suction apparatus; Salmonella Worthington was recovered from 18 babies who received suction. Recently, serovar Worthington has been found to be multidrug-resistant, challenging the treatment especially in neonates and elderly. 

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

Genetic characteristics: Serovar Worthington has been found to be polyphyletic with one lineage identified and one stand-alone singleton that does not cluster with any other Salmonella Worthington isolates. Salmonella Worthington isolates from preharvest turkey production sources pose both virulence and persistence by carrying virulence genes, such as invA, aceK, and sopB, along with resistance to many antibiotics (tetracycline, erythromycin, bacitracin, novobiocin, and rifampin). Salmonella Worthington has been reported as having acquired the third-generation cephalosporin resistance plasmid (bla_DHA-1-carrying IncFII plasmid) from Citrobacter amalonaticus. 

Animal reservoir: Serovar Sandiego Worthington has been commonly found in small turtles and turkeys including their environments, and also found in turkey flocks. 

Geographical distribution: Serovar Sandiego Worthington has been found in the United States and Canada, andIndonesia, reportedly, also in Uruguay, DenmarkHong Kong, India, Thailand, and BrazilPakistan.

OutbreaksHuman outbreaks: Several human outbreaks have been associated with S. Sandiego, mostly associated with small pet turtles. There was a report on an outbreak of food poisoning with approximately 200 cases in California in 1938. Two isolates of Salmonella Sandiego were obtained from this outbreak. Worthington. Below are some examples.

¹ Because of limitation of serological procedure at that time, this outbreak might be caused by pathogenic E. coli or Salmonella Worthington or both organisms

Border rejections: One case of border rejections associated with serovar Worthington was reported.Border Rejections: Multiple border rejections associated with serovar Sandiego have been reported during August 2020 to December 2021 and they were all linked to black pepper imported from Brazil to Germany. Some border rejections were linked to multiple serotypes. 

¹ Salmonella Sandiego and Kedougou were found.

² Salmonella Sandiego, Poona, Newport, Kiambu, Freetown, and Rubislaw were found.  

³ Salmonella Sandiego and Abaetetuba were found.

Recalls: One recall linked to serovar Worthington has been reportedRecalls: There have been no recent recalls linked to this serovar.

¹ This recall was caused by  multistate human outbreak linked to Salmonella Sandiego and Salmonella enterica subspecies IIIb, linked to ready-to-eat Spring Pasta Salad from Hy-Vee brand grocery stores. 

Relevant links and references:

a multistate outbreak.  Daniella brand mangoes grown in Mexico were recalled.

Relevant links:

1. httpshttp://www.cdcjstor.govorg/salmonella/small-turtles-10-15/index.htmlhttpstable/3859636?seq=3
2. https://wwwacademic.foodsafetynewsoup.com/trstmh/article/2013103/02/more-salmonella-infections-tied-to-tiny-turtles/#.V0C2kkY5X4Yhttp4/390/1918003?login=true
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1821928/proquest.com/docview/304631473?pq-origsite=gscholar&fromopenview=true&sourcetype=Dissertations%20&%20Theses
4. https://doi.org/10.1111/zph.13174www.sciencedirect.com/science/article/pii/S0168160503003301?via%3Dihub#BIB20
5. https://www.liebertpubfoodsafetynews.com/doi2012/epdf/10.1089/1076629026046969710/after-salmonella-outbreaks-growers-are-told-mangoes-are-high-risk-fruit/
6. https://www.cdcfrontiersin.govorg/journals/mmwrmicrobiology/previewarticles/mmwrhtml/mm5249a3.htm10.3389/fmicb.2025.1547190/full