Kauffman–White classification

The Kauffmann -White scheme ( currently correct, but unusual name: White- Kauffmann -Le Minor scheme) is used in bacteriology classification system for representatives of the Enterobacteriaceae genus Salmonella. It allows the serological classification of varieties and serotypes (also called " serovars " called ). In the complete Kauffmann -White scheme than 2500 different serovars of Salmonella are classified. Salmonella, which are closely related to species of the genus Escherichia, are pathogens and can both animals through the food chain infect humans. Infectious diseases with this transmission are also known as zoonoses.

History

In 1880, Karl Joseph Eberth and Robert Koch discovered the causative agent of human typhoid ( then, now called Eberthella typhosa Salmonella Typhi ), 1885 identified Daniel Elmer Salmon, after which the genus Salmonella was named, the causative agent of " hog cholera " ( S. choleraesuis ). In animals other Salmonella species were ( as S. typhimurium (mouse typhoid ) and S. abortusovis ( abortion of sheep ) ) found. With the classical methods of microbiology - for example, biochemical characteristics, such as differences in the utilization of various sugars (see also Colourful row ) - to let these pathogens due to their close relationship not differ from each other. Only on the basis of serological characteristics, a classification of this group of pathogens was possible. 1926, the British bacteriologist Philip Bruce White, a scheme for classification of Salmonella on serological base that was developed and expanded by the Danish bacteriologist Fritz Kauffmann 1933-1978. This extension takes place even today, at intervals of several years published the French bacteriologist Michel Popoff update the schema. The last update was published in 2007. Between ten and 20 new serotypes are annually recorded and described in these updates. In collaboration with the World Health Organization are Popoff at longer intervals updated Kauffmann-White schema in book form out ..

Nomenclature of Salmonella

See Also: Main article Salmonella

The nomenclature of the Salmonella species is very complex. First, Salmonella was named after the clinical point of (name of disease and host ). As it was recognized that the host specificity of some species does not exist - S. typhimurium and S. choleraesuis are pathogenic for humans - one designated as an independent new serovars of Salmonella species after the place where the first strain of the new species was isolated. In 2005, the decision-making committee decided ( Judicial Commission ) of the International Committee on Systematics of Prokaryotes ( ICSP ) that the genus Salmonella consists of two species, S. enterica and S. bongori, with S. enterica was divided into numerous subspecies.

This formal, created by microbiological taxonomists nomenclature is not in keeping with the traditional classification of Salmonella species and with the Kauffmann'schen Artbenennung due to the serovars. With this naming principle, however, are the Specialists in microbiology and infectious disease for decades familiar, so this is actually wrong nomenclature is still widely used today and is also used in the examples in the following article.

Basics of the Kauffmann-White scheme

The principle of the Kauffmann-White scheme

When creating a Kauffmann-White scheme with, for example, three different Salmonella strains are three antisera directed against these strains as detection reagents are available. In a first series of experiments, the reactions of the antisera against the respective parental strain and the other two strains are quantified. In a second series of experiments the antisera be pretreated prior to quantification by the non-homologous strains. This pre-treatment is also called pre-adsorption. The experimental results are summarized in tabular form (4 : strong, 2: middle; 0: no reaction):

There are differences and similarities between the three strains, strain 1 and 3 show similar response patterns are thus serologically identical. Strains 1 and 3 have with respect to the clade 2 both similarities and differences, one could also strains 1 and 3 in an artificial system, the determinants ( or factors ) A and B assign, strain 2, the determinants B and C. One could these factors but also α in an alternative scheme with the Greek letter β, and γ, respectively. If a newly discovered strain of Salmonella with another, completely new type antigen patterns are included in this system, the extended scheme will look like this:

Since the antigens of stem 4 with any antigen of strains 1 to 3 show cross-reactions, this strain is assigned in this hypothetical scheme, the determinant D (or in the alternative scheme δ ). Other newly isolated strains with differing antigen patterns can be incorporated into this scheme.

The Kauffmann -White scheme is ultimately based on the empirical evaluation of antigen -antibody cross-reactions with antisera präadsorbierter the surface antigens of a Salmonella strain.

Name and nature of the antigens

Salmonella have three different surface antigens of H, O, and Vi antigens are known. As these names were introduced, nothing was known about the function and precise localization of these antigens.

The term H was first used to describe the swarm behavior of Proteus mirabilis. In semi-solid agar to P. mirabilis and Salmonella move thanks to its peritrichous (ie over the entire cell surface distributed ) flagella on quickly, the appearance of a swarming colony resembles a hint that the human breath while breathing on it in the form of water droplets of a glass plate leaves. H- antibodies are directed against the scourge proteins. Most Salmonella serovars have two different types of plague antigens. These are referred to as phases. In a single colony mainly occurs a phase. At a frequency of 10-3 to 10-5 there is a change from one to the other in this clone. That is:

• One of One Hundred and one of tens of thousands of cells in a colony moves to another phase.
• The phenotype of the individual cell is monophasic, the genotype and the population, however, are biphasic. Only a few serovars (eg, Salmonella enteritidis, Salmonella typhi ) are exclusively monophasic, ie have only one flagellar antigen. The H antigens of the first phase of wear as a designation letter, the second phase of the Arabic numerals, rare letters.

The O originally stood for without breath, that means these bacteria not rave on an agar plate. The O- antigens were first found in unbegeißelten bacterial strains. O- antibodies are directed against the lipopolysaccharide of the cell surface. A distinction is made between main O- antigens that determine the group membership of the serovars and minor -O- antigens. The minor -O- antigens usually come in many serovars before ( example, all Salmonella strains of O - groups A, B, and D antigen O: 12) and are thus, for classification purposes of minor importance.

The term Vi represents an additional surface antigen, which was initially made ​​primarily responsible for virulence; However, it is a special case of a capsule antigen represents the O antigen -containing lipopolysaccharide is coated with the thin layer of the Vi antigen, a polysaccharide. Vi - antigens are only present in Salmonella typhi, Salmonella paratyphi and Salmonella dublin C and prevent a reaction of the bacterial O- antibodies.

Practical application of antigen -antibody reactions

Before carrying out the antigen -antibody reactions preliminary experiments are performed to verify that nonspecific agglutination to take place. These little bacteria material on a slide triturated in physiological saline, and the suspension is observed against a black background ( black construction paper, black tile ). If the suspension remains milky for about 5 minutes, no spontaneous agglutination takes place. In order to provide security that will actually work with a Salmonella strain that can ( an antiserum that recognizes all antigens ) a positive control be carried out against O- antigens with a omnivalenten antiserum. To some bacterial material is triturated with the antiserum. After about two minutes on a black background clearly visible agglutinates should occur. This process is called slide agglutination.

The following provision is first determined using group-specific O- antigens in the slide agglutination group membership. After that is determined using the H antisera by slide agglutination with the present scourge phase. This demonstrates a difference: the antigen -antibody aggregates are firm and grainy at the O- antigen, while they are at the H antigen flaky and not very stable. If the first phase of the H- antigen determined, the determination of the second phase. To a swarming is prepared containing the appropriate H- antiserum. The swarms of bacteria belonging to the first phase is thereby suppressed. Only those who have switched to the second phase, can move under these conditions. After incubation overnight can be determined by agglutination with appropriate H - antisera with bacterial material from the Schwärmzone the second phase.

The combination of O antigens, H antigens of the first and second phase of this serovar Salmonella strain from the Kauffmann -White scheme can be determined. see also

A simple Kauffmann -White scheme

The following table lists some important Salmonella serovars are classified according to the Kauffmann -White scheme, the classical nomenclature is used:

Selection of the antisera

The effort to produce a complete stock of antisera for the implementation of a complete Kauffmann-White scheme and to manage is large. This is done primarily in national reference laboratories. Most labs only hold a certain number of antisera available, with the choice of antisera oriented to the most likely to be treated Salmonella serovars. In order to obtain results that are comparable between laboratories, the WHO has prescribed standards for the production of antisera.

A frequently encountered selection looks like this:

Laboratories that deal with typhoid germs, keep antisera against Vi - antigens prepared.

A set of " rapid diagnosis Sera " (rapid diagnostic sera or RDS) is also applied: It is used for the determination of frequently occurring H antigens with the exception of iH. Provided that agglutination ( an antiserum which recognizes one or more H - antigens ), and a non-specific antiserum is positive with a polyvalent H- specific antiserum, the RDS three antisera are used to identify the H- antigen. From the pattern of agglutination - Nichtagglutination the respective H- antigen can be determined.

• E = polyvalent antigens for the eh, enx, etc.
• G = polyvalent antigens for the gm, gp, etc.
• L = lv for polyvalent antigens, lw, etc.

Recent Developments

The conventional method of determining the composition of the surface antigens is time and material consuming. The simultaneous detection of O and H antigens is desirable. To this end, according to the Kauffmann -White scheme selected antibodies were applied in a protein microarray on a glass slide and treated with fluorescent dyes labeled Salmonella cells. However, this miniaturization is not yet routine in the diagnostic laboratory.