Lancefield grouping

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Lancefield grouping is grouping catalase-negative, coagulase-negative bacteria 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,[3] and as of 2018, Lancefield designations are still often used to communicate medical microbiological test results in the United States. Enterococcus, formerly known as Group D Streptococcus, was believed to be a member of the genus Streptococcus until 1984, after the Lancefield criteria were devised, and so were included in the original Lancefield grouping.[4] Many - but not all - species of streptococcus are beta-hemolytic. Notably, Enterococcus and Streptococcus bovis (Lancefield Group D) are not beta-hemolytic.[5] 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, and two groups that lack the Lancefield carbohydrate antigen: Streptococcus pneumoniae and viridans streptococci.[6]

Classification[edit]

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

References[edit]

  1. ^ Todar.net/themicrobialworld/gonorrhea.html. Lectures in Microbiology. 2009.  Missing or empty |title= (help);
  2. ^ Isenberg, Henry D. 1992. Clinical microbiology procedures handbook. Washington, D.C.: American Society of Microbiology.
  3. ^ 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 126867Freely accessible. PMID 12364372. 
  4. ^ 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 2132252Freely accessible. PMID 19870148. 
  5. ^ Priloska, G. "Virulence factors and antibiotic resistance in Enterococcus faecalis isolated from urine samples". Prilozi. 29 (1): 57–66. PMID 18709000. 
  6. ^ Isenberg, H. D., & American Society for Microbiology. (1992). Clinical microbiology procedures handbook. Washington, D.C: American Society of Microbiology.