Authors:
Towers RJ, Carapetis JR, Currie BJ, Davies MR, Walker MJ, Dougan G, Giffard, PM
Authors notes:
PLoS ONE. 2013;8(9):e73851.
Keywords:
Streptococcus pyogenes, strains, distribution, populations, Northern Territory, Indigenous
Abstract:
The Indigenous population of the Northern Territory of Australia (NT) suffers from a very high burden of Streptococcus pyogenes disease, including cardiac and renal sequelae.
The aim of this study was to determine if S. pyogenes isolated from this population represent NT endemic strains, or conversely reflect strains with global distribution.
goeBURST analysis of MLST allelic profiles and neighbour-joining trees of the MLST allele sequences revealed that a large proportion of the known global S. pyogenes MLST-defined diversity has now been found in the NT.
Specifically, fully sequence typed NT isolates encompass 19% of known S. pyogenes STs and 43% of known S. pyogenes MLST alleles.
These analyses provided no evidence for major NT-endemic strains, with many STs and MLST alleles shared between the NT and the rest of the world.
The relationship between the number of known Minim types, and the probability that a Minim type identified in a calendar year would be novel was determined.
This revealed that Minim types typically persist in the NT for >1 year, and indicate that the majority of NT Minim types have been identified.
This study revealed that many diverse S. pyogenes strains exhibit global scale mobility that extends to isolated populations.
The burden of S. pyogenes disease in the NT is unlikely to be due to the nature of NT S. pyogenes strains, but is rather a function of social and living conditions.