Salmonella Hadar

Background: Salmonella enterica subsp. enterica serovar Hadar (antigenic formula 6,8:z10:e,n,x) is a serovar of the O:8 (C₂-C₃) serogroup. S. Hadar is a common serovar in the U.S. and Europe. Serovar Hadar is associated with turkey and other birds, and is commonly found in ground turkey and chicken meat. In Europe, this serovar emerged in 1971. In England, before 1971, only eight human cases reported; by 1979 a total of 1,600 human salmonellosis cases were confirmed to be caused by S. Hadar. 

Rep strainv 

S. Hadar has been isolated in the U.S., where it is among the top ten serovars from non-clinical non-human sources. In Europe, serovar Hadar is the 4^th most common serovar isolated from humans. In two countries of Asia, Thailand and China, this serovar has also been reported. In Thailand, serovar Hadar was reported in food (chicken and duck meat). Reports of acquisition of S. Hadar in travelers returning from Africa suggest a distribution of this serovar in Africa. In the U.S, this serovar is the most common serovar isolated from turkey. 

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

Genetic characteristics: As a consequence of the serovar Hadar emergence, a phage typing scheme was developed, this included 24 recognized phage types. The strain isolated from an outbreak associated with turkey burgers occurred in the U.S. in 2011 showed resistance to several antibiotics commonly used to treat salmonellosis (ampicillin, amoxicillin/clavulanate, cephalothin, and tetracycline). Among 64 Hadar isolates collected from different patients from 2005 to 2010 in Switzerland, 71.8% of them showed resistance to nalidixic acid. While 40.6% of the isolates were resistant to the β-lactam antibiotic ampicillin, they remained sensitive to the third-generation cephalosporin cefotaxime. All Hadar strains Nógrády et al. analyzed showed profound growth suppression. Prior colonization of chickens with Hadar strain 18 effectively prevented superinfection by S. Enteritidis, Typhimurium, Virchow and Saintpaul.

Animal reservoir: The main reservoirs of serovar Hadar are turkey flocks and turkey meat. However, chickens, ducks and swine are also sources of this serovar. 

Geographical distribution: Serovar Hadar has been reported worldwide such as the US. 

Human outbreaks: There were multiple human outbreaks of Salmonella Hadar. Below are examples.  

Border rejections:

¹ Salmonella Hadar and Kottbus were both found. 

Recalls:

¹ Plainville Brands, LLC, issued the recall because of the Salmonella Hadar outbreak.

² Product was (presumably) no longer on the market.    

Relevant links:

1. https://pubmed.ncbi.nlm.nih.gov/3729881/
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC9152617/
3. https://academic.oup.com/femsle/article/218/1/127/532259
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC11384159/#:~:text=Historically%2C%20outbreaks%20of%20foodborne%20Salmonella,to%20the%20backyard%20poultry%20market.
5. https://archive.cdc.gov/www_cdc_gov/salmonella/hadar-04-21/details.html#:~:text=As%20of%20May%2017%2C%202021%2C%20a%20total%20of%2033%20people,No%20deaths%20were%20reported.
6. https://archive.cdc.gov/#/details?q=https://www.cdc.gov/salmonella/hadar-live-poultry-07-12/index.html&start=0&rows=10&url=https://www.cdc.gov/salmonella/hadar-live-poultry-07-12/index.html
7. https://web.archive.org/web/20140122214727/https://www.cdc.gov/salmonella/hadar0411/040411/index.html
8. https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(05)70209-7.pdf
9. https://pubmed.ncbi.nlm.nih.gov/11078117/#:~:text=In%20August%201997%2C%20an%20outbreak,had%20symptoms%20of%20acute%20gastroenteritis.
10. https://pubmed.ncbi.nlm.nih.gov/9517880/
11. https://webgate.ec.europa.eu/rasff-window/screen/notification/468397
12. https://www.fsis.usda.gov/recalls?keywords=Salmonella&page=1
13. https://webgate.ec.europa.eu/rasff-window/screen/notification/431922