Lancefield grouping is a system of classification that classifies

catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting t ...

-negative

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacte ...

cocci A coccus (plural cocci) is any bacterium or archaeon that has a spherical, ovoid, or generally round shape. Bacteria are categorized based on their shapes into three classes: cocci (spherical-shaped), bacillus (rod-shaped) and spiral ( of whi ...

based on the carbohydrate composition of bacterial

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...

s found on their

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

s. The system, created by

Rebecca Lancefield Rebecca Craighill Lancefield (January 5, 1895 – March 3, 1981). p.227 was a prominent American microbiologist. She joined the Rockefeller Institute for Medical Research (now Rockefeller University) in New York in 1918, and was associated with ...

, was historically used to organize the various members of the family

Streptococcaceae Streptococcaceae are a family of Gram-positive bacteria, placed within the order Lactobacillales. Representative genera include ''Lactococcus'', ''Lactovum'', and ''Streptococcus ''Streptococcus'' is a genus of gram-positive ' (plural ) or ...

, which includes the genera ''

Lactococcus ''Lactococcus'' is a genus of lactic acid bacteria that were formerly included in the genus ''Streptococcus'' Group N1. They are known as homofermenters meaning that they produce a single product, lactic acid in this case, as the major or only pr ...

'' and ''

Streptococcus ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...

'', but now is largely superfluous due to explosive growth in the number of streptococcal species identified since the 1970s. However, it has retained some clinical usefulness even after the taxonomic changes, and as of 2018, Lancefield designations are still often used to communicate medical microbiological test results.

Enterococcus ''Enterococcus'' is a large genus of lactic acid bacteria of the phylum Bacillota. Enterococci are gram-positive cocci that often occur in pairs (diplococci) or short chains, and are difficult to distinguish from streptococci on physical charact ...

, formerly known as Group D Streptococcus, were classified as members of the genus Streptococcus until 1984 and were included in the original Lancefield grouping. Many - but not all - species of streptococcus are

beta-hemolytic ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...

. Notably, Enterococci and ''

Streptococcus bovis ''Streptococcus bovis'' (''S. bovis'') is a species of Gram-positive bacteria that in humans is associated with urinary tract infections, endocarditis, sepsis, Ryan K.J. and C.G. Ray CG (editors). 2004. ''Sherris Medical Microbiology'' (4th ed.). ...

'' (Lancefield Group D) are not beta-hemolytic. Though there are many groups of streptococcus, only five are known to commonly cause disease in immune-competent human beings: Group A, Group B, both members of Group D (''Streptococcus gallolyticus'' and ''Streptococcus infantarius'', both members of the ''Streptococcus bovis'' group), and two groups that lack the Lancefield carbohydrate antigen: ''

Streptococcus pneumoniae ''Streptococcus pneumoniae'', or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic (under aerobic conditions) or beta-hemolytic (under anaerobic conditions), aerotolerant anaerobic member of the genus Streptococcus. They are ...

'' and

viridans streptococci The viridans streptococci are a large group of commensal streptococcal Gram-positive bacteria species that are α-hemolytic, producing a green coloration on blood agar plates (hence the name "viridans", from Latin "vĭrĭdis", green), although so ...

Classification

*Group A - ''

Streptococcus pyogenes ''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus ''Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They are ...

'' *Group B - ''

Streptococcus agalactiae ''Streptococcus agalactiae'' (also known as group B streptococcus or GBS) is a gram-positive coccus (round bacterium) with a tendency to form chains (as reflected by the genus name ''Streptococcus''). It is a beta-hemolytic, catalase-negative, a ...

'' *Group C - '' Streptococcus equisimilis'', ''

Streptococcus equi ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...

'', ''

Streptococcus zooepidemicus ''Streptococcus zooepidemicus'' is a Lancefield group C streptococcus that was first isolated in 1934 by P. R. Edwards, and named Animal pyogens A. It is a mucosal commensal and opportunistic pathogen that infects several animals and humans, but m ...

'', ''

Streptococcus dysgalactiae ''Streptococcus dysgalactiae'' is a gram positive, beta-haemolytic, coccal bacterium belonging to the family ''Streptococcaceae''. It is capable of infecting both humans and animals, but is most frequently encountered as a commensal of the alim ...

'' *Group D - ''

Enterococcus faecalis ''Enterococcus faecalis'' – formerly classified as part of the group D ''Streptococcus'' system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus ''Enterococcus'', ''E ...

'', ''

Enterococcus faecium ''Enterococcus faecium'' is a Gram-positive, gamma-hemolytic or non- hemolytic bacterium in the genus ''Enterococcus''. It can be commensal (innocuous, coexisting organism) in the gastrointestinal tract of humans and animals, but it may also be ...

'', ''

Enterococcus durans ''Enterococcus durans'' is a species of ''Enterococcus''. It is a gram-positive, catalase- and oxidase-negative, coccus bacterium. The organism is also a facultative anaerobic organism. Prior to 1984, it was known as ''Streptococcus durans''. C ...

'' and ''

'' *Group F, G & L - ''

Streptococcus anginosus ''Streptococcus anginosus'' is a species of ''Streptococcus ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria) ...

'' *Group H - ''

Streptococcus sanguis ''Streptococcus sanguinis'', formerly known as ''Streptococcus sanguis'', is a Gram-positive facultative anaerobic coccus species of bacteria and a member of the Viridans Streptococcus group. ''S. sanguinis'' is a normal inhabitant of the healt ...

'' *Group K - ''

Streptococcus salivarius ''Streptococcus salivarius'' is a species of spherical, gram-positive, facultative anaerobic lactic acid bacteria that is both catalase and oxidase negative. ''S. salivarius'' colonizes (usually in chains) the oral cavity and upper respiratory ...

'' *Group L - ''

'' *Group M & O - ''

Streptococcus mitis ''Streptococcus mitis'' is a mesophilic alpha-hemolytic species of ''Streptococcus'' that inhabits the oral cavity. It is coccus (spherical shaped), gram-positive, catalase negative, and facultative anaerobe. It was previously classified as ''Str ...

'' *Group N - ''

Lactococcus lactis ''Lactococcus lactis'' is a Gram-positive bacterium used extensively in the production of buttermilk and cheese, but has also become famous as the first genetically modified organism to be used alive for the treatment of human disease. ''L. lact ...

'' *Group R & S - ''

Streptococcus suis ''Streptococcus suis'' is a peanut-shaped, Gram-positive bacterium, and an important pathogen of pigs. Endemic in nearly all countries with an extensive pig industry, ''S. suis'' is also a zoonotic disease, capable of transmission to humans from ...

'' Other ''

'' species are classified as 'non-Lancefield streptococci'.

References

{{Clinical microbiology techniques Bacteriology Microbiology techniques