Serotyping of Salmonella: Introduction, Types and Risk Factors of Salmonella Infection
Serotyping is a type of epidemiological marker.
It works on the principle of agglutination.
agglutination or clumping: positive
No agglutination or clumping: Negative
On this basis, Salmonellacan differentiate whether Salmonella enterica serotype Typhi or Paratyphi and so on.
Serotype O antigen
Salmonella enterica serotype Typhi 9, 12, Vi
( Weak H2S production in SIM or TSI agar)
Salmonella enterica serotype Paratyphi A 1, 2, 12
( No H2S production in SIM or TSI agar)
Salmonella enterica serotype Paratyphi B 1, 4, 5, 12
( Strong H2S production and gas in SIM or TSI agar)
Serotypes are groups within a single species of microorganisms like bacteria or viruses, that share distinctive surface structures. For instance, Salmonella bacteria look similar under the microscope but can be separated into many serotypes based on two structures on their surface:
The outermost portion of the bacteria’s surface covering, called the O antigen or somatic antigen where as ; and slender threadlike structure, called the H antigen or flagellar antigens , that is part of the flagella. The O antigens are distinguished by their different chemical make-up. The H antigens are distinguished by the protein content of the flagella. Each O and H antigen has a unique code number that helps to determine the serotype based on the distinct combination of O and H antigens as shown above picture.
More than 2,500 serotypes have been described so far for Salmonella; among them, less than 100 serotypes account for most human infections.
The nature and distribution of serotypes vary from serotype to serotype. e.g. Some serotypes are only found in one kind of animal or in a single place, where as others are found in many different animals and all over the world. Some can cause especially severe illnesses when they infect people; while others cause milder illnesses.
List of some common serotypes of Salmonella
Salmonella enterica serovar Typhimurium
Salmonella enterica serovar Enteritidis
Salmonella enterica serovar Newport
Salmonella enterica serovar Heidelberg
Salmonella enterica serovar Javiana
Risk Factors of Salmonellosis
People with weakened immune systems
children under five years old
Serotyping is a subtyping test based on differences in microbial (e.g., viral or bacterial) surfaces.
Serology refers to the antibodies that form because of a viral or bacterial infection.
Serotyping is sometimes referred to as serology, but this is technically inaccurate.
A serotype is also called serovar, is a distinct variation within a species of bacteria or virus or among immune cells of different individuals.
Salmonella enterica has more than 2300 serotypes based on “O” antigen, H antigen, and Vi antigen (in Kauffman- White scheme).
#Salmonella serotyping antisera
#Shigella antisera for serotyping-Shigella antisera for Shigella flexneri Shigella dysenteriae Shigella boydii
#Vibrio antisera for serotyping: Vibrio cholerae antisera for serotyping are-
#Vibrio cholerae darting motility, growth on various media, biochemical tests, and serotyping live: Vibrio cholerae -Darting motility positive, growth on various media( Nutrient agar, Macconkey agar, and TCBS agar) biochemical tests(TSI, SIM, Urease, Citrate, O-F, and decarboxylation) and serotyping fully demonstrated