Lancefield classification of streptococci

Dieses kann durch spezifische Antikörper als Antigen erkannt und so identifiziert werden. Group A betahemolytic Streptococci Streptococcus pyogenes Morphology.

Antibodies to this protein M were shown to be type strain specific and antibacterial through opsonic activity.

Lancefield classification of streptococci. Die Lancefield-Klassifikation ist ein Einteilungsverfahren für Streptokokken das auf der Analyse des C-Polysaccharids in der Bakterienzellwand beruht. Dieses kann durch spezifische Antikörper als Antigen erkannt und so identifiziert werden. In der Lancefield-Klassifikation werden die verschiedenen Serogruppen mit Großbuchstaben bezeichnet.

Lancefield grouping is a serological method for classifying streptococci into one of 20 groups designated by a letter based on the presence of polysaccharide and teichoic acid antigens in the bacterial cell wall Lancefield 1933. In the medical setting the most important groups are the alpha-hemolytic streptococci S. Pneumoniae and Streptococcus viridans group and the beta-hemolytic streptococci of Lancefield groups A and B also known as group A strep and group B strep.

What is the basis of Lancefield classification. Lancefield grouping is grouping catalase-negative coagulase-negative bacteria based on the carbohydrate composition of bacterial antigens found on their cell walls. In 1928 Dr.

Rebecca Lancefield described a system for typing group A streptococci GAS 1 based on the variable antigenic properties of a heat stable surface protein. Antibodies to this protein M were shown to be type strain specific and antibacterial through opsonic activity. Classification of Streptococcus 1.

Classification on the basis of Oxygen requirement. Aerobic or facultative anaerobes. On the basis of haemolytic pattern on sheep blood agar.

Shows greenish discoloration around. Lancefield developed serotyping system for classification of beta-hemolytic streptococci or gamma based on the antigenic composition of specific cell wall carbohydrates C- Carbohydrates or C- Substrate Viridians streptococci Strep. Pneumonia are not grouped under Lancefield Classification have no group-specific antigen.

18 group-specific antigens Lancefield groups were known. Classification of Streptococci Browns classification Lancefield grouping Griffith typing 4. Group A betahemolytic Streptococci Streptococcus pyogenes Morphology.

Spherical to oval cocci Arranged in chains more in liquid medium Why chain formation. Extension of the Lancefield classification for group A streptococci by addition of 22 new M protein gene sequence types from clinical isolates. Facklam RF1 Martin DR Lovgren M Johnson DR Efstratiou A Thompson TA Gowan S Kriz P Tyrrell GJ Kaplan E Beall B.

Beta-hemolytic streptococci are further subdivided according to the Lancefield classification. This classification which dates back to the biologist Rebecca C. Lancefield in 1933 distinguishes more than 20 groups of streptococci.

It is based on the serological detection of the different antigenicity of the C-substance Cengl. Carbohydrate a cell wall polysaccharide in the. To describe the Lancefield classification of Streptococci and other identifying characteristics of the organisms 2.

To describe the spectrum of diseases caused by S. Pyogenes Group A Strep including non-suppurative sequelae of localized infections 3. To describe the virulence factors of S.

Pyogenes and their relationship to streptococcal. Streptococci are spherical organisms that grow in chains because of incomplete separation after division of the cells Figure 1They were first described in 1874 by Billroth who used the term Streptococcus from two Greek words. Streptos chain kokhos berry.

In the beginning streptococci were classified according to the disease they caused. However thanks to advances in. Streptococcus pyogenes S.

Pyogenes is also known as beta-hemolytic group A streptococcus or Lancefields group A strep GAS. It is the most pathogenic bacterium in. Streptococci are divided into three groups Fig.

β -hemolytic streptococci which are classified by Lancefield grouping α -hemolytic and γ -hemolytic streptococci. Rebecca Craighill Lancefield 1895 1981 was an American bacteriologist. She is eponymously known for her serological classification of beta haemolytic streptococci into Lancefield groups.

She was also amongst the first to show that Strep. Pyogenes infection was the cause of.