What does O157 mean and what is the O antigen?

Among the EHEC serotypes, O157:H7, which expresses somatic (O) antigen 157 and flagellar (H) antigen 7, causes serious morbidity and large disease outbreaks, making this bacterium one of the most important food-borne and waterborne pathogens worldwide (12, 27).

What is O and H in E. coli?

Pathogenic E. coli strains can be categorized based on elements that can elicit an immune response in animals, namely: O antigen: part of lipopolysaccharide layer. K antigen: capsule. H antigen: flagellin.

What does the H stand for in E. coli O157:H7?

Abstract. Enterohemorrhagic Escherichia coli O157:H7 is a major foodborne pathogen causing severe disease in humans worldwide.

How do you identify E. coli serotype?

The traditional method for identifying E. coli uses antibodies to test for surface antigens: the O- polysaccharide antigens, flagellar H-antigens, and capsular K-antigens (described below). There are currently ∼186 different E. coli O-groups and 53 H-types, so serotyping is highly complex.

What is the function of O antigen?

The O antigen is an extremely variable surface polysaccharide of Gram-negative bacteria. This variation is thought to allow the various clones of a species each to present a surface that offers a selective advantage in the niche occupied by that clone.

Where is the O antigen located?

O antigen is exposed on the very outer surface of the bacterial cell, and, as a consequence, is a target for recognition by host antibodies.

Which three antigens are present on E. coli?

coli based on the somatic (O), flagellar (H) and capsular polysaccharide antigens (K) is used in epidemiology.

What is the difference between E. coli and E. coli O157:H7?

A noteworthy difference between E. coli O157:H7 and the non-pathogenic strains was that incubation in the presence of 12.5% soy sauce allowed the growth of E. coli O157:H7 strains but reduced the viable cell numbers of non-pathogenic E. coli strains.

What disease is caused by E. coli O157:H7?

coli O157:H7 can lead to the development of hemolytic uremic syndrome (HUS). HUS is a serious life-threatening disease that can cause kidney damage or failure and other serious problems. Hospitalization is often required because transfusions of blood, plasma exchange, or kidney dialysis may be necessary.

What do you mean by serotype?

Serotypes are groups within a single species of microorganisms, such as bacteria or viruses, which share distinctive surface structures.

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