**5.1 Somatic O antigen (Ag O)**

308 Salmonella – A Dangerous Foodborne Pathogen

To survive in the inflammatory process and the development of bactericidal proteins produced by PMN, a set of genes must be activated, especially those in the complex PhoPQ.

Salmonella possess the general characteristics of the Enterobacteriaceae and intrinsic

2. Often through their mobile ciliature peritrichous (rarely stationary), non-spore forming;

Some strains do not obey all these characters, in the case of Erwinia, which does not reduce nitrates, Shigella dysenteriae serotype 1 (SD1) that does not have catalase, Salmonella

The main biochemical characteristics for identification of Salmonella (Humbert et al., 1998)

The production of hydrogen sulfide from thiosulfate (presence of thiosulfate reductase);

**4. Biochemical characteristics of salmonella** 

Eight main characters determine the Enterobacteriaceae, they are:

5. Bacilli that ferment glucose with or without gas production;

**4.2 Differential characters of the genus** *Salmonella* 

The frequent decarboxylation of lysine and ornithine;

The growth on Simmons citrate medium.

7. Bacilli that do not have cytochrome oxidase (Hanes, 2003; ICMSF, 1996);

 The absence of an active urease, tryptophan or phenylalanine deaminase; Lack of production of indole and acetoin (Voges-Proskauer test negative);

Salmonella can have three types of diagnostic antigens of interest (Dumas, 1958).

Fig. 1. Salmonella posses a flagellar antigen (H), somatic (O) and a surface antigen Vi

differential characters.

**4.1 Family characters** 

1. Bacilli Gram negative;

3. Bacteria that grow on ordinary media; 4. Aero-anaerobic bacteria optional;

6. Bacteria that reduce nitrate to nitrite;

8. Bacilli that have a catalase.

pullorum-galinarum is immobile.

**5. Antigens of Salmonella** 

are:

The O antigen is an antigen of the wall. O antigens are carried by chains specific lipopolysaccharide (LPS). The O antigen has properties immunizing is a complex containing a protein, a polysaccharide and a phospholipid compound. We distinguish 67 O factors depending on the nature of the sugars used in the construction of oligosaccharide units of the polysaccharide (Humbert et al., 1998). O antigens are composed of a lipid fraction called lipid A is responsible for toxic effects, or basal part of the core and the support of the specific polysaccharide (Gledel and Corbion, 1991). Antigens are classified as major factors O and O factors accessories. The major factors are related to the presence of certain sugars (abequose for O: 4, tyvélose for O: 9) (Humbert et al., 1998). The somatic antigen is stable and it is resistant to alcohol and phenol for two and a half hours at a 100 ° C (Dumas, 1958).
