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. As a consequence of the S. Hadar emergence, a phage typing scheme was developed, this included 35 recognized phage types. In 2011, an outbreak associated with turkey burgers occurred in the U.S., the outbreak strain showed resistance to several antibiotics commonly used to treat salmonellosis (ampicillin, amoxicillin/clavulanate, cephalothin, and tetracycline).
Animal reservoir: The main reservoirs of S. Hadar are turkey flocks and turkey meat. However, chickens, ducks and swine are also sources of this serovar. In the U.S, this serovar is the most common serovar isolated from turkey.
Geographical distribution: 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 4th 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.
Outbreaks: Outbreaks of Salmonella Hadar have been identified in the U.S. and Europe, one large outbreak with > 2,000 cases was reported in Spain.
Year | Location | Associated source | Number of cases |
2012 | US-multistate | Live poultry | 46 |
2011 | US-multistate | Turkey burgers | 12 |
2005 | Spain | Pre-cooked chicken | 2138 |
1997 | Italy | Roasted rabit | 24 |
1994 | Italy | Meat salad | 448 |
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