title: Biogeography and virulence of Staphylococcus aureus.
abstract: BACKGROUND
  Staphylococcus aureus is commonly carried asymptomatically in the human anterior nares and occasionally enters the bloodstream to cause invasive disease. Much of the global diversity of S. aureus remains uncharacterised, and is not clear how disease propensity varies between strains, and between host populations.
  
  
  METHODS
  We compared 147 isolates recovered from five kindergartens in Chengdu, China, with 51 isolates contemporaneously recovered from cases of pediatric infection from the main hospital serving this community. The samples were characterised by MLST, the presence/absence of PVL, and antibiotic resistance profiling.
  
  
  RESULTS
  Genotype frequencies within individual kindergartens differ, but the sample recovered from cases of disease shows a general enrichment of certain MLST genotypes and PVL positive isolates. Genotypes under-represented in the disease sample tend to correspond to a single sequence cluster, and this cluster is more common in China than in other parts of the world.
  
  
  CONCLUSIONS
  Virulence propensity likely reflects a synergy between variation in the core genome (MLST) and accessory genome (PVL). By combining evidence form biogeography and virulence we demonstrate the existence of a "native" clade in West China which has lowered virulence, possibility due to acquired host immunity.
authors: Department of Pediatrics, West China Second Hospital, Sichuan University, Chengdu, Sichuan, PR China.
authors: Juan
authors: J
authors: Fan
authors: Min
authors: M
authors: Shu
authors: Ge
authors: G
authors: Zhang
authors: Wei
authors: W
authors: Zhou
authors: Yongmei
authors: Y
authors: Jiang
authors: Yu
authors: Y
authors: Zhu
authors: Guihua
authors: G
authors: Chen
authors: Sharon J
authors: SJ
authors: Peacock
authors: Chaomin
authors: C
authors: Wan
authors: Wubin
authors: W
authors: Pan
authors: Edward J
authors: EJ
authors: Feil
mesh_terms: D002353:Carrier State; D002648:Child; D002681:China / Q000453:epidemiology; D005843:Geography; D006801:Humans; D007231:Infant, Newborn; D009296:Nasal Cavity / Q000382:microbiology; D010802:Phylogeny; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000472:pathogenicity*; D014774:Virulence