icRK and CovR polymorphisms in Streptococcus mutans strains associated with cardiovascular infection

Autor(es)

Oliveira, Leticia T. ^[1] ; Alves, Livia A. ^[1] ; Harth-Chu, Erika N. ^[1] ; Nomura, Ryota ^[2] ; Nakano, Kazuhiko ^[2] ; Mattos-Graner, Renata O. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Dept Oral Diag, Piracicaba Dent Sch, Piracicaba, SP - Brazil

^[2] Osaka Univ, Grad Sch Dent, Dept Pediat Dent, Osaka - Japan

• Tipo de documento: Artigo Científico
• Fonte: Journal of Medical Microbiology; v. 70, n. 12 2021.
• Citações Web of Science: 0

Resumo

Introduction. Streptococcus mutans, a common species of the oral microbiome, expresses virulence genes promoting cariogenic dental biofilms, persistence in the bloodstream and cardiovascular infections. Gap statement. Virulence gene expression is variable among S. mutans strains and controlled by the transcription regulatory systems VicRK and CovR. Aim. This study investigates polymorphisms in the vicRK and covR loci in S. mutans strains isolated from the oral cavity or from the bloodstream, which were shown to differ in expression of covR, vicRK and downstream genes. Methodology. The transcriptional activities of covR, vicR and vicK were compared by RT-qPCR between blood and oral strains after exposure to human serum. PCR-amplified promoter and/or coding regions of covR and vicRK of 18 strains (11 oral and 7 blood) were sequenced and compared to the reference strain UA159. Results. Serum exposure significantly reduced covR and vicR/K transcript levels in most strains (P<0.05), but reductions were higher in oral than in blood strains. Single-nucleotide polymorphisms (SNPs) were detected in covR regulatory and coding regions, but SNPs affecting the CovR effector domain were only present in two blood strains. Although vicR was highly conserved, vicK showed several SNPs, and SNPs affecting VicK regions important for autokinase activity were found in three blood strains. Conclusions. This study reveals transcriptional and structural diversity in covR and vicR/K, and identifies polymorphisms of functional relevance in blood strains, indicating that covR and vicRK might be important loci for S. mutans adaptation to host selective pressures associated with virulence diversity. (AU)

• Processo FAPESP: 15/22967-6 - Análise da influência dos reguladores transcricionais VicRK e CovR na baixa susceptibilidade de cepas Streptococcus mutans isoladas de sangue à opsonização pelo sistema complemento
• Beneficiário: Letícia Tank Oliveira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 18/02054-4 - Identificação de fatores que modulam a susceptibilidade de Streptococcus sanguinis à imunidade mediada pelo sistema complemento
• Beneficiário: Renata de Oliveira Mattos Graner
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/19899-4 - Identificação de fatores que modulam a susceptibilidade de Streptococcus sanguinis à imunidade mediada pelo sistema complemento
• Beneficiário: Lívia Araújo Alves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado