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 first isolated in 1937 from a young turkey and a chick by Dr. Pomeroy. The name of Worthington came from Worthington, Minnesota, where a hatchery that the poult of this isolate was purchased. Serovar Worthington is the 2nd most common nontyphoidal Salmonella serovar isolated from human infections in India during 2001-2005.  

The most common source of serovar Worthington is turkey, turkey ceca, and its production environment. This serovar has been reported in milk powder contamination, vegetables, and seafood. However, serovar Worthington has been frequently reported to cause infection especially in neonatal cases and the pediatric ward. 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 fatality. 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 at Indonesian hospital. The outbreak to newborn babies in the ward also occurred in hospital in Hong Kong in August 1974 leading to 1 from 13 cases died due to meningitis but the outbreak cause was unable to identified. However, the second outbreak occurred in five weeks after with infected five newborns and this time revealed that the outbreak caused by the contamination in tubing system of a suction apparatus which was used for baby's oropharyngeal suction. The outbreak causing by the same contamination also happened in Pakistan in early 1990s. Salmonella Worthington was recovered from 18 babies who received suction. Recently, serovar Worthington likely becomes multidrug-resistant bacteria challenging for treatment especially in neonates and elderly. 

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

Genetic characteristics: Serovar Worthington has been found to be polyphyletic with 1 lineage and 1 stand-alone singleton. Salmonella Worthington isolates from preharvest turkey production sources pose both virulence and persistence by carrying virulence genes which are invA, aceK, and sopB together with resistance to many antibiotics (tetracycline, erythromycin, bacitracin, novobiocin, and rifampin). Salmonella Worthington has been reported on its ability either acquire third-generation cephalosporin resistance plasmid (bla_DHA-1-carrying IncFII plasmid) from Citrobacter amalonaticus or transfer its own resistance genes consisting of extended-spectrum cephalosporins, monobactam, and fluoroquinolone to Escherichia coli. 

Animal reservoir: Serovar Worthington has been commonly found in turkeys including their environments.

Geographical distribution: Serovar Worthington has been found in the United States, Indonesia, Hong Kong, India, Thailand, and Pakistan.

Human outbreaks: Several human outbreaks have been associated with S. 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.

Recalls: One recall linked to serovar Worthington has been reported.

¹ This recall was caused by a multistate outbreak.  Daniella brand mangoes grown in Mexico were recalled.

Relevant links and references:

1. https://www.jstor.org/stable/3859636?seq=3

2. https://academic.oup.com/trstmh/article/103/4/390/1918003?login=true

3. https://www.proquest.com/docview/304631473?pq-origsite=gscholar&fromopenview=true&sourcetype=Dissertations%20&%20Theses

4. https://www.sciencedirect.com/science/article/pii/S0168160503003301?via%3Dihub#BIB20

5. https://www.foodsafetynews.com/2012/10/after-salmonella-outbreaks-growers-are-told-mangoes-are-high-risk-fruit/