Lancefield-classification of streptococcus

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 ( C=engl. carbohydrate), a cell wall polysaccharide in the bacterial wall.

According to Lancefield, the individual serogroups are named with capital letters (groups A-W). Streptococci of serogroup A (Streptococcus pyogenes) occur in more than 80 variants due to the different antigenicity of the M-protein. Note: Viridans streptococci ("oral streptococci") and pneumococci do not use this classification because they lack the polysaccharide that acts as an antigen. Enterococci contain the group antigen D. Streptococcus agalactiae has the B antigen of the C substance. The bacteria are infectious agents in animals (udder infections in cows). In humans, this streptococcal species occurs as a colonizer of the intestinal tract and vagina. It can be transmitted perinatally and lead to invasive infections.

• Lancefield Group A:
• Streptococcus pyogenes path. for humans
• Lancefield group B
• Streptococcus agalactiae path. for animals/ rarely humans
• Lancefield group C
• Streptococcus equi path. for humans and animals
• Streptococcus zooepidermicus path. for humans and animals
• Streptococcus equisimilis path. for humans and animals
• Streptococcus galactiae path. for humans and animals
• Streptococcus pyog. haemolyt. anim. path. for humans and animals
• Lancefield group D
• Enterococcus faecalis n .-path./limited path. for humans
• Enterococcus faecium n.-path./limited path. for humans
• Enterococcus durans n.-path./limited path. for humans
• Enterococcus liquefaciens n.-path./limited path. for humans
• Enterococcus bovis n.-path./limited path. for humans
• Lancefield group E
• Streptococcus uberis n.-path.for humans
• Streptococcus infrequens n.-path. for humans
• Lancefield group F
• Streptococcus minutus limited path. for humans
• Lancefield group G
• Streptococcus anginosus n.-path. for humans
• Lancefield group H
• Streptococcus sanguis
• Streptococcus dysgalactiae n.-path. for humans
• Lancefield group K-M (unspecified) n.-path. for humans and animals
• Lancefield group N
• Streptococcus lactis limited path. for humans
• Streptococcus cremoris limited path. for humans
• Lancefield group O-S unspecified non-pathogenic to humans