Expression of both M protein and hyaluronic acid capsule by group A streptococcal strains results in a high virulence for chicken embryos

Karl Hermann Schmidt, Elisabeth Günther, Harry S. Courtney

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The human pathogenic microorganism Streptococcus pyogenes can resist against phagocytic attack of human granulocytes. Streptococcal M protein and hyaluronic acid were identified as virulence factors involved in this protection. So far, no experiments have been reported which describe the contribution of both components together in one system. We used the chicken embryo as an in vivo phagocytosis model to investigate the role of both components on the virulence of streptococci. For this, isogeneic mutants of group A streptococcal strains (GAS) which lack hyaluronic acid capsule (cap-) or M protein (M-) expression were used for infection and their virulence was compared with laboratory strains which had lost their ability to produce one or both virulence factors after long-time laboratory passages on blood agar. The experiments revealed that strains producing both M protein and hyaluronic capsule were highly virulent. Only 1-10 colony-forming units were enough to cause a 50% lethality of 12-day-old chicken embryos. Those strains lacking one of these components showed a significant decrease in virulence. Finally, strains which failed to express either hyaluronic acid or M protein showed an additional tenfold decrease in virulence. This indicates a partial contribution of both M protein and hyaluronic acid to the virulence of GAS in the chicken embryo.

Original languageEnglish (US)
Pages (from-to)169-173
Number of pages5
JournalMedical Microbiology and Immunology
Volume184
Issue number4
DOIs
StatePublished - Jan 1 1996

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Hyaluronic Acid
Capsules
Virulence
Chickens
Embryonic Structures
Virulence Factors
Proteins
Streptococcus pyogenes
Streptococcus
Phagocytosis
Granulocytes
Agar
Stem Cells
Infection

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology
  • Microbiology (medical)

Cite this

Expression of both M protein and hyaluronic acid capsule by group A streptococcal strains results in a high virulence for chicken embryos. / Schmidt, Karl Hermann; Günther, Elisabeth; Courtney, Harry S.

In: Medical Microbiology and Immunology, Vol. 184, No. 4, 01.01.1996, p. 169-173.

Research output: Contribution to journalArticle

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