In vivo characterization of the psa genes from Streptococcus pneumoniae in multiple models of infection

Microbiology (Reading). 2002 May;148(Pt 5):1483-91. doi: 10.1099/00221287-148-5-1483.


Differential fluorescence induction technology was used to identify promoters of Streptococcus pneumoniae genes that are expressed during lung infection of the mouse. Among the promoter clones that were identified multiple times was the psa promoter, which drives expression of the psaBCA operon. These genes have been identified previously and shown to encode a manganese permease system as well as play a role in the virulence of this organism. Mutations in psaB, psaC or psaA result in growth limitation in low manganese. The expression of the psa operon was examined in vivo and the virulence of deletion mutants of psaB, psaC, psaA and psaBCA was assessed in four different animal models of infection. The psa promoter was induced more than ten-fold in vivo using an intraperitoneal chamber implant model. The psaB, psaC and psaA mutants were completely attenuated in systemic, respiratory tract and otitis media infections. In addition, these mutants were unable to grow in an implanted peritoneal chamber, but growth was restored by the addition of manganese to the chambers.

MeSH terms

  • ATP-Binding Cassette Transporters / genetics*
  • Adhesins, Bacterial
  • Animals
  • Bacterial Proteins*
  • Carrier Proteins / genetics
  • Diffusion Chambers, Culture
  • Disease Models, Animal*
  • Gene Deletion
  • Gene Library
  • Green Fluorescent Proteins
  • Implants, Experimental
  • Lethal Dose 50
  • Lipoproteins / genetics
  • Luminescent Proteins
  • Manganese / pharmacology
  • Membrane Proteins / genetics
  • Membrane Transport Proteins*
  • Mice
  • Otitis Media / microbiology*
  • Peritoneal Cavity / microbiology
  • Promoter Regions, Genetic / genetics*
  • Respiratory Tract Infections / microbiology*
  • Streptococcus pneumoniae / drug effects
  • Streptococcus pneumoniae / genetics*
  • Streptococcus pneumoniae / growth & development
  • Streptococcus pneumoniae / pathogenicity


  • ATP-Binding Cassette Transporters
  • Adhesins, Bacterial
  • Bacterial Proteins
  • Carrier Proteins
  • Lipoproteins
  • Luminescent Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • PsaA protein, Streptococcus
  • psaB protein, Streptococcus
  • psaC protein, Streptococcus
  • Green Fluorescent Proteins
  • Manganese