Background: Salmonella enterica subsp. enterica serovar Choleraesuis has the antigenic formula 6,7:c:1,5. Within S. Choleraesuis there are two biovars, S. Choleraesuis var. Kunzendorf and S. Choleraesuis var. Decatur. There are also two other serovoars with the same antigenic formula as S. Choleraesuis: S. Paratyphi C. and S. Typhisuis. Differentiation is accomplished through biochemical analysis, see Table 1 below. S. Choleraesuis is utilized as an H2S negative QC strain in the USDA Microbiology Laboratory Guidebook, Chapter 4: Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, Siluriformes (Fish) Products, Carcass and Environmental Sponges. S. Choleraesuis was one of the first types of Salmonella discovered. Theobald Smith and Daniel Salmon discovered Salmonella Choleraesuis in 1885 while studying swine diseases. This serovar is highly host adapted to swine and causes swine paratyphoid. Pigs that have been infected can shed the organism for up to 12 weeks resulting environmental contamination and spread of the disease among the herd. Human cases from this serovar in the United States are rare, but nearly half of infections are invasive and can be severe. While it is not one of the leading serovars associated with nontyphoidal salmonellosis (NTS), S. Choeraesuis is one of the top servors implicated in NTS fatalities. In the 1990s, S. Choleraesuis was one of the top 10 serovars isolated from human cases in Taiwan. Improvements in swine husbandry, including vaccination of pigs, has significantly reduced the occurrence of Choleraesuis in Taiwan. Outbreaks from consuming contaminated pork are rare.
Table 1: Differention of serovars with antigenic formula 6,7:c:1,5
| Dulcitol | H2S | Mucate | Agglutination of H:c in sera | |||
|---|---|---|---|---|---|---|
| S1 | S2 | S3 | ||||
Paratyphi C (Vi+ or Vi-) | + | + | - | - | - | + |
| Choleraesuis | - | - | - | - | + | - |
| Choleraesuis var. Kunzendorf | - | + | - | - | + | + |
| Choleraesuis var. Decatur | + | + | + | + | + | + |
| Typhisuis | - | - | - | - | + | + |
Animal reservoir: Swine is the reservoir of this serovar
Geographical distribution: Serovar Choleraesius has been reported in North America, Asia, and Europe. Most cases are in pigs.
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