Association of intrastrain phase variation in quantity of capsular polysaccharide and teichoic acid with the virulence of Streptococcus pneumoniae

J Infect Dis. 1998 Feb;177(2):368-77. doi: 10.1086/514205.


The pneumococcus undergoes spontaneous phase variation between an opaque and a transparent colony form. In an animal model of systemic infection following intraperitoneal inoculation of mice, the opaque phenotype was significantly more virulent than the transparent for each of 3 strains examined. The opaque phenotype was associated with 1.2- to 5.6-fold greater amounts of capsular polysaccharide compared with the transparent using a sandwich ELISA. A similar technique comparing the amount of total teichoic acid showed that the transparent phenotype had 2.1- to 3.8-fold more immunodetectable teichoic acid. This difference was confirmed by comparing the incorporation of [3H]choline into teichoic acid. Cell fractionation revealed that variation in quantity of incorporated choline was due to differences in cell wall-associated teichoic acid. Results suggest that the pneumococcus phase varies between a virulent form with more capsular polysaccharide and less teichoic acid and an avirulent form with less capsular polysaccharide and more teichoic acid.

Publication types

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

MeSH terms

  • Animals
  • Bacterial Capsules / analysis
  • Bacterial Capsules / immunology
  • Bacterial Capsules / metabolism*
  • Blotting, Western
  • Cell Wall / metabolism
  • Choline / metabolism
  • DNA, Bacterial / genetics
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Mice
  • Mice, Inbred BALB C
  • Phenotype
  • Pneumococcal Infections / metabolism
  • Pneumococcal Infections / microbiology*
  • Polysaccharides, Bacterial / analysis
  • Polysaccharides, Bacterial / immunology
  • Polysaccharides, Bacterial / metabolism*
  • Streptococcus pneumoniae / genetics
  • Streptococcus pneumoniae / metabolism*
  • Streptococcus pneumoniae / pathogenicity*
  • Teichoic Acids / analysis
  • Teichoic Acids / immunology
  • Teichoic Acids / metabolism*
  • Transformation, Genetic
  • Virulence / genetics


  • DNA, Bacterial
  • Polysaccharides, Bacterial
  • Teichoic Acids
  • Choline