Description

The serological typing of a Salmonella strain occurs through two subsequent phases which lead to the definition of the serogroup and the serotype. The first step is to determine the O somatic specificity. The second step is to determine the H flagellar specificity, monophasic or diphasic.

MONOPHASIC: The flagella of bacteria have the same specificity. (e.g. S. Typhi 9,12 (Vi): d)

BIPHASIC: bacteria can alternatively express 2 different specificities; (e.g.: S. Paratyphi B 1, 4, 5, 12,: b: 1,2)

Some serotypes such as S. Typhi and S. Dublin may present the Vi capsular antigen (virulence factor) which may not allow agglutination with Salmonella anti-O agglutinating sera. Identification of flagellar specificity (monophasic or diphasic) is conducted with polyvalent and monovalent serological tests, diluting a colony or a drop of microbial culture on a glass slide, in a drop of polyvalent or monovalent flagellar serum to be tested. Most Salmonella serotypes are diphasic, i.e. they possess different flagellar antigens, classified as first and second phase. Defining a diphasic serotype requires recognition of either flagellar or ciliary phases. Sometimes one ciliary phase can be stronger than the other, so as to prevent the agglutination of the weaker one, thus making the PHASE INVERSION test necessary. The test allows you to detect the second phase using the immobilizing properties of the anti-H serum, which, when added to the SWARM AGAR medium, allows you to immobilize all the bacteria with a flagellated antigen corresponding to the specificity of the added serum, allowing the recognition of both phases ( ciliary and flagellar), necessary for identification. 

Packing:

• Cod. 18.0404 Pack 100 test tubes 10 ml (ready-to-use medium)