What is serotype?

What Does serotype Mean

The concept of serotype is not part of the dictionary of the Royal Spanish Academy ( RAE ). The term, however, is often used in the field of medicine .

It is classified as serotype a microorganism that can cause infection and is classified according to antigens exhibiting on the surface of their cells. It should be noted that an antigen is a substance that, when it enters an animal-type organism, causes a defensive reaction .
Differentiation of serotypes makes it possible to distinguish between microorganisms. There are different populations of the same species: each one can be a specific serotype. This type of distinction is very relevant in the field of epidemiology .

Since the body reacts according to the serotype of each microorganism, the immune system can provide an effective defensive response against one serotype but insufficient against another of the same microorganism.
There are different types of tests to establish serotypes. What is sought is to analyze how microorganisms react when in contact with the antibodies of a certain serum. To classify them, liposaccharides in gram negative bacteria, virulence factors, the existence of exotoxins (toxins that a microorganism such as a protozoan, a bacterium or a fungus secretes outside the cell), bacteriophages, plasmids or any other type can be taken into account. another feature that serves to distinguish two elements of a particular species.
Some of the tests that are performed to classify serotypes are the following: immunoblot (also known as Western blot or electroblot ); ELISA ("Enzyme-Linked Immunoborbent Assay"); immunofluorescence (can be both direct and indirect ); agglutination; precipitate; complement fixation; neutralization; DNA hybridization.
Serotypes, also known as serovars , therefore bring together microorganisms that share specific antigenic characteristics . Microorganisms can also be differentiated as morphotypes (due to morphology), pathotypes (due to their pathogenic properties depending on the host), biotypes (due to physiological and biochemical qualities) and other types.
The different serotypes of pneumococcus , HIV and dengue virus are some of the groups that have demanded and are demanding different medicinal treatments to preserve or restore human health .
Another case in which this concept is very relevant is the Infectious Bronchitis virus , also known as IBV . Its various isolates have been divided into various serotypes, according to the neutralization test that uses cultures of tracheal organs or embryonated eggs.

On the other hand, they can also be identified through RT-PCR ( " reaction chain real - time polymerase" from the English "real time polymerase chain reaction") or RFLP ( "length polymorphisms of restriction fragments ", From the English" restrictive fragment length polymerase ").
These techniques are used to group the strains according to their genotype. It should be mentioned, on the other hand, that the results do not always yield a classification in which the strains of genotypes and serotypes coincide, although there is usually an acceptable correlation between the two methods. Various serotypes are known about IBV and this is of great importance, since in many cases the different serotypes are not protected, although certain strains of the virus can act very effectively to offer cross protection against genotypes or serotypes.
One of the most outstanding characteristics of the Infectious Bronchitis virus is its ability to mutate very easily and in a short time, which can lead to the appearance of new serotypes or variant viruses. It is necessary to determine its prevalence before deciding to apply vaccines that include these viruses, in the same way that the position of the laws on this issue must be taken into account.