title: Clonal structure of Streptococcus sanguinis strains isolated from endocarditis cases and the oral cavity.
abstract: A collection of Streptococcus sanguinis strains from patients with endocarditis (n = 21) and from the oral cavity (n = 34) was subjected to a multi-locus sequence typing analysis using seven housekeeping genes, carbamoyl-phosphate synthetase (carB), Co/Zn/Cd efflux system component (czcD), d-alanyl-d-alanine ligase (ddl), DNA polymerase III (dnaX), glucose-6-phosphate dehydrogenase (gdh), DNA-directed RNA polymerase, beta subunit (rpoB) and superoxide dismutase (sodA). The scheme was expanded by the inclusion of two the putative virulence genes, bacitracin-resistance protein (bacA) and saliva-binding protein (ssaB), to increase strain discrimination. Extensive intra-species recombination was apparent in all genes but inter-species recombination was also apparent with strains apparently harbouring gdh and ddl from unidentified sources and one isolate harboured a sodA allele apparently derived from Streptococcus oralis. The recombination/mutation ratio for the concatenated housekeeping gene sequences was 1.67 (95% confidence limits 1.25-2.72) and for the two virulence genes the r/m ratio was 3.99 (95% confidence limits 1.61-8.72); recombination was the major driver for genetic variation. All isolates were distinct and the endocarditis strains did not form distinct sub-clusters when the data were analysed using ClonalFrame. These data support the widely held opinion that infecting S. sanguinis strains are opportunistic human pathogens.
authors: Department of Microbiology, King's College London, London, UK.
authors: T
authors: T
authors: Do
authors: S C
authors: SC
authors: Gilbert
authors: J
authors: J
authors: Klein
authors: S
authors: S
authors: Warren
authors: W G
authors: WG
authors: Wade
authors: D
authors: D
authors: Beighton
mesh_terms: D002999:Clone Cells; D003773:Dental Plaque / Q000382:microbiology*; D004697:Endocarditis, Bacterial / Q000097:blood / Q000382:microbiology*; D005798:Genes, Bacterial / Q000235:genetics*; D020043:Genes, Essential / Q000235:genetics; D014644:Genetic Variation; D006801:Humans; D058885:Multilocus Sequence Typing; D009894:Opportunistic Infections / Q000382:microbiology; D010802:Phylogeny; D011995:Recombination, Genetic; D013298:Streptococcus sanguis / Q000235:genetics*