Increased frequency of genomic alterations in Staphylococcus aureus during chronic infection is in part due to phage mobilization

J Infect Dis. 2004 Feb 15;189(4):724-34. doi: 10.1086/381502. Epub 2004 Jan 29.


We assessed the nature and frequency of genome alterations in Staphylococcus aureus during chronic lung infection in patients with cystic fibrosis (CF) and during colonization of the nares in healthy individuals. Only individuals harboring the same S. aureus clone on consecutive samplings were included in the present study. Clone definition was based on pulsed-field gel electrophoresis (PFGE) analysis. Minor fragment variations in consecutive clones were interpreted as genome alterations. The frequency of genome alterations was significantly higher in S. aureus derived from patients with CF (mean time, 1.03 years) than in isolates derived from healthy individuals (mean time, 13.4 years). In total, 19 S. aureus strain pairs showing genome alterations were available for molecular analysis to clarify the nature of recombinational events in the host environment. In 8 cases, genome alteration could be linked to phage mobilization. Phage conversion of beta-toxin production was evident in 7 pairs. In 1 strain pair, changes in the PFGE pattern were accompanied by deletion of a phage similar to ETA. Obviously, phage mobilization plays an important role in vivo. During long-term lung infection in patients with CF, the specific host response and/or the regular exposure to antibiotics exercises strong selective pressure on the pathogen. Genome plasticity may facilitate the adaptation to various host conditions.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Typing Techniques
  • Base Sequence
  • Cystic Fibrosis / complications
  • Cystic Fibrosis / microbiology
  • DNA Primers
  • Electrophoresis, Gel, Pulsed-Field
  • Genome, Bacterial*
  • Humans
  • Mutation*
  • Open Reading Frames
  • Polymerase Chain Reaction
  • Reference Values
  • Restriction Mapping
  • Sputum / microbiology
  • Staphylococcal Infections / physiopathology*
  • Staphylococcal Infections / virology
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / genetics*
  • Staphylococcus aureus / virology*
  • Streptococcus Phages / genetics
  • Streptococcus Phages / physiology*


  • DNA Primers