S. Hadar¶

At a Glance


Antigenic Formula	`6,8:z10:e,n,x`
Serogroup	O:8 (C2-C3)
NCBI Pathogen Detection	View isolates

Background Information¶

Salmonella enterica subsp. enterica serovar Hadar (antigenic formula 6,8:z₁₀:e,n,x) is a serovar of the O:8 (C₂-C₃) serogroup. 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 serovar Hadar. Serovar Hadar is among thetop ten serovars from non-clinical non-human sourcesin the US. Also, this serovar is the most common serovar isolated from turkey in the US. In Europe, serovar Hadar is the 4^th most common serovar isolated from humans. Reports of acquisition of serovar Hadar intravelersreturning from Africa suggest a distribution of this serovar in Africa.

Genetic Characteristics¶

Serovar Hadar has been found to be polyphyletic with two lineages identified and two stand-alone singletons that do not cluster with any other Salmonella Hadar isolates. 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 withturkey burgersoccurred 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. REPTDK01 is a REP (reoccurring, emerging, or persisting) strain of Salmonella Hadar that has been linked to illnesses and outbreaks in the United States.

Animal Reservoir¶

The main reservoirs of serovar Hadar are turkey flocks and turkey meat. However, chickens, ducks and swineare also sources of this serovar.

Geographical Distribution¶

Serovar Hadar has been reported worldwide such as the US.

Human/Animal Outbreaks¶

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

Year	Location	Associated source	Number of cases
2021	US: multistate	Ground turkey	33
2012	US: multistate	Live poultry	46
2011	US: multistate	Turkey burgers	12
2005	Spain	Pre-cooked chicken	2138
1997	Italy	Roasted rabit	29
1994	Italy	Meat salad	448

Border Rejections¶

Year	Exporting country	Importing country	Associated source	Product category
2021	Hungary	Italy	Duck fillets¹	Poultry meat and poultry meat products

¹ Salmonella Hadar and Kottbus were both found.

Recalls¶

Year	Location	Recalled food	Type
2021	US	Ground turkey¹	Poultry meat and poultry meat products
2020	Latvia	Turkey minced meat²	Poultry meat and poultry meat products

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

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