Presence of fibronectin-binding protein gene prtF2 in invasive group A streptococci in tropical Australia is associated with increased internalisation efficiency

Microbes Infect. 2005 Mar;7(3):421-6. doi: 10.1016/j.micinf.2004.11.015. Epub 2005 Feb 25.

Abstract

The fibronectin-binding proteins (FnBPs) PrtF1 and PrtF2 are considered to be major group A streptococcal virulence factors, mediating adherence to and internalisation of host cells. The present study investigated an association between the presence of prtF1 and prtF2 genes and internalisation efficiency in group A streptococci (GAS) isolated from patients with invasive disease. Of the 80 isolates tested, 58 (73%) had prtF1 and 71 (89%) possessed prtF2. Three isolates (4%) had neither gene, seven (9%) had prtF1 only, 19 (24%) had prtF2 only and 51 isolates (64%) had both prtF1 and prtF2. prtF2-positive isolates internalised up to three times more efficiently than isolates that had prtF1 alone (P<0.001), and 1.5-fold better than isolates that had neither gene. No significant association was found between internalisation efficiency and presence of the prtF1 gene. Analysis of the fibronectin-binding repeat domain (FBRD) of prtF2 revealed that this gene can contain 2, 3, 4 or 5 repeat regions and that five repeat regions conferred very high internalisation efficiency in invasive GAS isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / genetics*
  • Amino Acid Sequence
  • Australia / epidemiology
  • Humans
  • Molecular Sequence Data
  • Sequence Alignment
  • Streptococcal Infections / epidemiology
  • Streptococcal Infections / microbiology
  • Streptococcus pyogenes / genetics*
  • Streptococcus pyogenes / pathogenicity

Substances

  • Adhesins, Bacterial
  • fibronectin-binding proteins, bacterial