An insert in the covS gene distinguishes a pharyngeal and a blood isolate of Streptococcus pyogenes found in the same individual

Microbiology (Reading). 2010 Oct;156(Pt 10):3085-3095. doi: 10.1099/mic.0.042614-0. Epub 2010 Jul 15.


Expression of the extensive arsenal of virulence factors by Streptococcus pyogenes is controlled by many regulators, of which CovRS is one of the best characterized and can influence ∼15 % of the genome. Animal models have established that mutants of covRS arise spontaneously in vivo resulting in highly invasive organisms. We analysed a pharyngeal and a blood isolate of S. pyogenes recovered from the same individual 13 days apart. The two isolates varied in many phenotypic properties including SpeB production, which were reflected in transcriptomic analyses. PFGE, multilocus sequence typing and partial sequencing of some key genes failed to show any differences except for an 11 bp insert in the covS gene in the blood isolate which caused a premature termination of transcription. Complementation of a fully functional covS gene into the blood isolate resulted in high expression of CovS and expression of speB. These results, showing a pharyngeal and a blood isolate from a single individual differing by a simple insertion, provide evidence for the model that regulatory gene mutations allow S. pyogenes to invade different niches in the body.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Base Sequence
  • Blood / microbiology
  • Child
  • DNA, Bacterial / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial
  • Genetic Complementation Test
  • Histidine Kinase
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Male
  • Molecular Sequence Data
  • Multilocus Sequence Typing
  • Mutagenesis, Insertional
  • Oligonucleotide Array Sequence Analysis
  • Pharynx / microbiology
  • Phenotype
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Streptococcus pyogenes / classification
  • Streptococcus pyogenes / genetics*
  • Streptococcus pyogenes / isolation & purification
  • Streptococcus pyogenes / pathogenicity
  • Virulence Factors / genetics*


  • Bacterial Proteins
  • DNA, Bacterial
  • Intracellular Signaling Peptides and Proteins
  • Virulence Factors
  • CovS protein, Streptococcus pyogenes
  • Histidine Kinase

Associated data

  • GEO/GSE21316