Genetic linkage of exotoxin alleles and emm gene markers for tissue tropism in group A streptococci

J Infect Dis. 1999 Mar;179(3):627-36. doi: 10.1086/314631.


In group A streptococci, genetic markers for principal tissue reservoir are located within emm genes, which encode surface proteins that have a role in virulence. A worldwide collection of 160 isolates was evaluated for two traits: chromosomal emm gene markers for tissue tropism (designated patterns A-E), and bacteriophage-associated genes (speA and speC) encoding pyrogenic exotoxins. The speA and speC alleles of organisms harboring the emm marker for a pharyngeal reservoir (pattern A-C) differ from spe alleles that predominate in organisms with the emm marker for impetigo (pattern D). However, organisms that display the emm marker for both tissue sites (pattern E) are not intermediate for the distribution of either speA or speC alleles, but instead resemble pattern A-C isolates for speA and pattern D strains for speC. Statistically significant nonrandom associations between exotoxin alleles and emm patterns were observed but cannot be readily explained by niche separation alone.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Antigens, Bacterial / genetics
  • Bacterial Outer Membrane Proteins*
  • Bacterial Proteins / genetics*
  • Carrier Proteins / genetics*
  • Chromosome Mapping
  • Chromosomes, Bacterial / genetics
  • Exotoxins / genetics*
  • Genes, Bacterial
  • Genetic Linkage
  • Genetic Markers
  • Humans
  • Membrane Proteins*
  • Streptococcus Phages / genetics
  • Streptococcus pyogenes / genetics*
  • Streptococcus pyogenes / isolation & purification
  • Streptococcus pyogenes / pathogenicity*


  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • Exotoxins
  • Genetic Markers
  • Membrane Proteins
  • SpeA protein, Streptococcus pyogenes
  • erythrogenic toxin
  • streptococcal M protein