Lancefield grouping

Lancefield grouping is a system of classification that classifies catalase-negative Gram-positive cocci based on the carbohydrate composition of bacterial antigens found on their cell walls.[1] The system, created by Rebecca Lancefield, was historically used to organize the various members of the family Streptococcaceae, which includes the genera Lactococcus and Streptococcus, but now is largely superfluous due to explosive growth in the number of streptococcal species identified since the 1970s.[2] However, it has retained some clinical usefulness even after the taxonomic changes,[1] and as of 2018, Lancefield designations are still often used to communicate medical microbiological test results in the United States.

Reagents used for Lancefield grouping

Enterococcus, formerly known as Group D Streptococcus, were classified as members of the genus Streptococcus until 1984 and were included in the original Lancefield grouping.[3] Many - but not all - species of streptococcus are beta-hemolytic. Notably, Enterococci and Streptococcus bovis (Lancefield Group D) are not beta-hemolytic.[4] 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 and viridans streptococci.[2]

ClassificationEdit

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

ReferencesEdit

  1. ^ a b Facklam, R. (1 October 2002). "What happened to the streptococci: overview of taxonomic and nomenclature changes". Clinical Microbiology Reviews. 15 (4): 613–630. doi:10.1128/CMR.15.4.613-630.2002. PMC 126867. PMID 12364372.
  2. ^ a b Isenberg, Henry D. (1992). Clinical Microbiology Procedures Handbook. American Society of Microbiology. ISBN 978-1555810382.
  3. ^ Lancefield RC (1933). "A serological differentiation of human and other groups of hemolytic streptococci". J Exp Med. 57 (4): 571–95. doi:10.1084/jem.57.4.571. PMC 2132252. PMID 19870148.
  4. ^ Priloska, G (2008). "Virulence factors and antibiotic resistance in Enterococcus faecalis isolated from urine samples". Prilozi. 29 (1): 57–66. PMID 18709000.
  5. ^ Shewmaker, P. L.; Whitney, A. M.; Humrighouse, B. W. (2016-03-01). "Phenotypic, Genotypic, and Antimicrobial Characteristics of Streptococcus halichoeri Isolates from Humans, Proposal To Rename Streptococcus halichoeri as Streptococcus halichoeri subsp. halichoeri, and Description of Streptococcus halichoeri subsp. hominis subsp. nov., a Bacterium Associated with Human Clinical Infections". Journal of Clinical Microbiology. 54 (3): 739–744. doi:10.1128/JCM.03214-15. ISSN 0095-1137. PMID 26763962.