title: Multilocus sequence typing of Streptococcus mutans strains with the cbm gene encoding a novel collagen-binding protein.
abstract: OBJECTIVE
  Streptococcus mutans, an oral pathogen associated with infective endocarditis (IE), possesses two genes encoding collagen-binding proteins, namely cnm and cbm. In this study, we used multilocus sequence typing (MLST) of S. mutans with the cbm gene.
  
  
  METHODS
  Forty-five S. mutans strains including 15 strains with the cnm gene, 15 strains with the cbm gene, and 15 strains without these two genes were analysed by MLST. In addition, the collagen-binding properties as well as the abilities to adhere to and invade human umbilical vein endothelial cells (HUVEC) were also evaluated for all strains.
  
  
  RESULTS
  In the groups of cnm-positive and cbm-positive strains, all properties, including collagen binding, adhesion, and invasion were significantly greater than those of the cnm-cbm-negative group. Moreover, MLST revealed three clonal complexes of S. mutans possessing the cbm gene. These three clones showed no close relatedness with clones of strains containing the cnm gene. Among three clones harbouring the cbm gene, two clones belong to serotype k, and appeared to be associated with the pathogenesis of IE due to their strong collagen binding and relatively enhanced abilities to adhere to and invade endothelial cells. However, such properties were relatively weak in the other non-serotype k clone possessing the cbm gene.
  
  
  CONCLUSIONS
  MLST indicated a difference in evolution between S. mutans strains with the cbm gene and those with the cnm gene. In addition, this technique also suggested the importance of cbm-positive S. mutans clones relative to the pathogenesis of IE.
authors.affiliation: Department of Oral Microbiology, Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand. jinthana.lap@mahidol.ac.th
authors.forename: Jinthana
authors.initials: J
authors.lastname: Lapirattanakul
authors.forename: Ryota
authors.initials: R
authors.lastname: Nomura
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Nemoto
authors.forename: Shuhei
authors.initials: S
authors.lastname: Naka
authors.forename: Takashi
authors.initials: T
authors.lastname: Ooshima
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakano
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis* / Q000235:genetics; D001422:Bacterial Adhesion / Q000235:genetics; D015373:Bacterial Typing Techniques; D002352:Carrier Proteins / Q000235:genetics; D002999:Clone Cells; D024042:Collagen Type I / Q000378:metabolism*; D004697:Endocarditis, Bacterial / Q000382:microbiology; D061307:Human Umbilical Vein Endothelial Cells / Q000382:microbiology; D006801:Humans; D058885:Multilocus Sequence Typing; D011485:Protein Binding; D012703:Serotyping; D013295:Streptococcus mutans / Q000145:classification* / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D002352:Carrier Proteins; C488758:Cnm protein, Streptococcus mutans; D024042:Collagen Type I