Pneumococcus with the "6E" CPS locus produces serotype 6B capsular polysaccharide

Academic Article


  • Genetic studies of serogroup 6 isolates of Streptococcus pneumoniae identified putative serotype 6E. Although its capsular polysaccharide structure has not been elucidated, putative serotype 6E is described in an increasing number of studies as a potentially new serotype. We show here that SPEC6B, which is widely used as a target strain for serotype 6B opsonophagocytosis assays, has the genetic features of the putative serotype 6E but produces capsular polysaccharide identical to 6B capsular polysaccharide as determined by one-dimensional (1D) and 2D nuclear magnetic resonance (NMR). Thus, putative serotype 6E is a mere genetic variant of serotype 6B. Also, SPEC6B is appropriate as a target strain for serotype 6B opsonophagocytosis assays. This example illustrates the difficulties of assigning new bacterial serotypes based on genetic findings alone.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Burton RL; Geno KA; Saad JS; Nahm MH
  • Start Page

  • 967
  • End Page

  • 971
  • Volume

  • 54