Salmonella Choleraesuis

Background: Salmonella enterica subsp. enterica serovar Choleraesuis has the antigenic formula 6,7:c:1,5. There are four other Salmonella serovars with the same antigenic formula. S. Paratyphi C, S. Choleraesuis var. Kunzendorf, S. Choleraesuis var. Decatur, and S. Typhisuis all share a common antigenic formula. Differentiation is accomplished through biochemical analysis, see Table 1 below. S. Choleraesuis is utilized as an H₂S negative QC strain in the USDA-MLG. S. Choleraesuis was one of the first types of Salmonella discovered. Theobold 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 infection of other animals in 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. Cholerasuis 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 disease 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
	Dulcitol	H₂S	Mucate	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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Salmonella Choleraesuis