K. NakanoR. NomuraN. TaniguchiJ. LapirattanakulA. KojimaS. NakaP. SenawongseR. SrisatjalukL. GrönroosS. AlaluusuaM. MatsumotoT. OoshimaOsaka UniversityMahidol UniversityHelsinki University HospitalHelsingin Yliopisto2018-09-242018-09-242010-01-01Archives of Oral Biology. Vol.55, No.1 (2010), 34-39000399692-s2.0-72649091762https://repository.li.mahidol.ac.th/handle/20.500.14594/28843Objective: Streptococcus mutans, known to be a major pathogen of dental caries, is also considered to cause infective endocarditis. Its 120-kDa Cnm protein binds to type I collagen, which may be a potential virulence factor. In this study, we characterized S. mutans clinical strains focusing on the cnm gene encoding Cnm. Design: A total of 528 S. mutans strains isolated from Japanese, Finnish, and Thai subjects were investigated. Using molecular techniques, the distribution frequency of cnm-positive strains and location of the inserted cnm were analyzed. Furthermore, isogenic mutant strains were constructed by inactivation of the cnm gene, then their biological properties of collagen-binding and glucan-binding were evaluated. Southern hybridization of the genes encoding glucan-binding proteins was also performed. Results: The distribution frequency of cnm-positive strains from Thai subjects was 12%, similar to that previously reported for Japanese and Finnish subjects. Furthermore, the location of insertion of cnm was the same in all cnm-positive clinical isolates. As for the cnm-inactivated mutant strains constructed from 28 clinical isolates, their collagen-binding activity was negligible. In addition, glucan-binding activity in the cnm-positive clinical isolates was significantly reduced and corresponded to a lack of gbpA encoding glucan-binding protein A. Conclusions: Our results indicate that strains with cnm genes, the most crucial factor for the collagen-binding property of S. mutans, are detectable at similar frequencies over several different geographic locations. In addition, the common properties of these strains are a high level of collagen-binding activity and tendency for a low level of glucan-binding activity. © 2009 Elsevier Ltd. All rights reserved.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyDentistryMedicineArticleSCOPUS10.1016/j.archoralbio.2009.11.008