What is K antigen capsule?

The capsular or K-antigen is composed of high molecular weight polysaccharide and forms a dense, high molecular weight coat outside of the bacterial cells. Encapsulated pathogens can become invasive and cause septicemia due to their increased resistance to phagocytosis and complement-mediated killing.

What is K antigen bacteria?

Capsular polysaccharide (CPS) or K antigen is a covalently attached surface associated virulence factor that conceals the bacterial surface and helps it to escape from host self-defense mechanism (6–8).

What does K1 antigen do?

The K1 antigen is an important virulence determinant of Escherichia coli strains and has been shown to be associated particularly with neonatal meningitis, bacteraemia and septicaemia. Thus, its detection seems to be useful, especially in the case of E. coli strains isolated from pregnant women and newborns.

Is O antigen A capsule?

ABSTRACT. Group IV polysaccharide capsules are common in enteric bacteria and have more recently been described in nontyphoidal Salmonella species. Such capsules are known as O-antigen (O-Ag) capsules, due to their high degree of similarity to the O-Ag of the lipopolysaccharide (LPSO-Ag).

What are K antibodies in blood?

Anti-K is the next most common immune red cell antibody after those in the ABO and Rh system. Anti-K typically presents as IgG class alloantibody. Individuals lacking a specific Kell antigen may develop antibodies against Kell antigens when transfused with blood containing that antigen.

How does EPEC cause diarrhea?

Enteropathogenic Escherichia coli (EPEC) is a non-Shiga toxin-producing strain of E. coli that causes diarrhea via an “attaching and effacing” mechanism on the surface of enterocytes [1, 2].

What is H and O antigen?

The bacteria’s surface are covered with lipopolysaccharide (LPS). The outermost portion of the LPS is the O antigen. Flagella are whip-like tails that bacteria use to move around. Flagella is the whole structure, while the slender threadlike portion of the flagella is called the H antigen.

Does S typhi have a capsule?

S. Typhimurium lacks the Vi-Ag capsule but has been reported to produce an alternative capsular polysaccharide (15–17).

How many people have the K antigen?

Commonly but imprecisely called “Kell,” this is the most important antigen in the Kell blood group system. This antigen also goes by the name “KEL1.” While K is a relatively low-frequency antigen (present in only about 9% of Caucasians and 2% of African-Americans), it is very important for several reasons.

What causes anti-k antibody?

Examples of anti-K are usually produced in response to immunization by transfusion or pregnancy. They are usually IgG in nature and react primarily by the indirect antiglobulin test (IAT), but saline reactive/IgM examples have also been reported.