Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2016

Contrasting population structures, host ranges and phylogeography for two newly defined species in the Staphylococcus aureus complex: Staphylococcus argenteus and Staphylococcus schweitzeri . (#213)

Steven YC Tong 1 , Deborah Holt 1 , Simon R Harris 2 , Matthew TG Holden 2 , Stephen D Bentley 2 , Julian Parkhill 2 , Sharon J Peacock 2 , Matthew Ellington 2 , Frieder Schaumberg 3 , Georg Peters 3 , Bruno Pichon 4 , Angela Kearns 4 , Harry A Thorpe 5 , Edward J Feil 5 , Gemma G Murray 6 , John J Welch 6 , Jukka Corander 7 , Andrew C Steer 8 , Stephen R Ritchie 9 , Herminia de Lancastre 10 , Anne-Catrin Uhlemann 11 , Andrew E Simor 12 , Philip M Giffard 1
  1. Division of Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
  2. Wellcome Trust Sanger Institute, Cambridge, UK
  3. Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
  4. Public Health England, London, UK
  5. Department of Biology and Biochemistry, University of Bath, Bath, UK
  6. Department of Genetics, University of Cambridge, Cambridge, UK
  7. Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
  8. Royal Children's Hospital, Melbourne, Victoria, Australia
  9. Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
  10. Laboratory of Molecular Genetics, Universidade Nova de Lisboa (UNL), , Lisbon, Portugal
  11. Department of Medicine, Columbia University, New York, USA
  12. Sunnybrook Health Sciences Centre, Toronto, Canada

Recently, the species Staphylococcus argenteus (silver staph) and Staphylococcus schweitzeri have been described (1). Both are more closely related to S. aureus than is Staphylococcus simae, which was previously regarded as the closest relative of S. aureus. S. aureus, S. argenteus and S. schweitzeri may be regarded as the “S. aureus complex”. S. argenteus is a globally distributed human pathogen with similar virulence properties to S. aureus, and has also been identified in an African bat population. S schweitzeri to date has been identified in African non-human primates, once in a human carrier in Gabon, and the same African bat population shown to harbour S. argenteus. Here we report large scale comparative genomics of S. argenteus and S. schweitzeri. The genome sequences of 180 S. argenteus and 24 S. schweitzeri isolates were determined. The principal findings of bioinformatic analyses were: 1. As foreshadowed in analysis of a smaller collection of isolates, the species are highly divergent throughout the great majority of their core genomes, supporting their classification as separate species, 2. S. argenteus and S. schweitzeri are phylogenetic sister groups within the S. aureus complex, despite the close resemblance between S. aureus and S. argenteus as regards known host range and virulence properties, 3. The population structure of the sequenced S. argenteus isolates is discontinuous, consisting of seven highly conserved clonal complexes, indicating multiple genetic bottlenecks in the recent past, 4. There have been more instances of core genome horizontal transfer between S. aureus and S. schweitzeri than between S. argenteus and either of the other two species, and 5. S. argenteus is rapidly acquiring accessory genome elements characteristic of S. aureus. Our current model is that multiple cross species transfer events within the last 50 years have introduced S. argenteus into humans.

 

  1. (1) Tong SYC et al, 2015. Int J Syst Evol Microbiol. 65:15-22.