Whole genome sequence and phenotypic characterization of a Cbm+ serotype e strain of Streptococcus mutans

• Main Authors: Abranches, J. (Author), Avilés-Reyes, A. (Author), Barbieri, D. (Author), Freires, I.A (Author), Kajfasz, J.K (Author), Lemos, J.A (Author), Miller, J.H (Author)
• Format: Article
• Language: English
• Published: Blackwell Publishing Ltd 2018
• Subjects: 3' flanking region; 5' flanking region; Adhesins; adult; Article; bacitracin; bacterial cell wall; bacterial chromosome; bacterial DNA; bacterial genome; bacterial growth; bacterial protein; Bacterial Proteins; bacterial RNA; bacterial strain; bacterial virulence; bacteriocin; Bacteriocins; Base Composition; biofilm; Biofilms; carrier protein; Carrier Proteins; cell anchorage; cell surface; collagen; Collagen; collagen-binding proteins; controlled study; dental caries; Dental Caries; DNA base composition; DNA fragment; DNA purification; Endothelial Cells; endothelium cell; female; gene cluster; gene insertion; genetics; genome; Genome, Bacterial; glucose; glycosylation; growth inhibition; growth, development and aging; heterologous expression; human; Humans; immunofluorescence; intracellular invasion; isolation and purification; Lactococcus lactis; metabolism; microbiology; mortality rate; multigene family; Multigene Family; nonhuman; nucleotide sequence; operon; oxidative stress; Oxidative Stress; periodontitis; phenotype; Phenotype; phosphotransferase; physiology; protein expression level; reading frame; sequence analysis; Sequence Analysis; Serogroup; serotype; stop codon; Streptococcus gordonii; Streptococcus mutans; sucrose; transcription termination; transfer RNA; type strain; type VII secretion system; Type VII Secretion Systems; virulence; Virulence; virulence factor; Virulence Factors; Western blotting; whole genome sequencing; Whole Genome Sequencing; zone of inhibition
• Online Access: View Fulltext in Publisher

 We report the whole genome sequence of the serotype e Cbm+ strain LAR01 of Streptococcus mutans, a dental pathogen frequently associated with extra-oral infections. The LAR01 genome is a single circular chromosome of 2.1 Mb with a GC content of 36.96%. The genome contains 15 phosphotransferase system gene clusters, seven cell wall-anchored (LPxTG) proteins, all genes required for the development of natural competence and genes coding for mutacins VI and K8. Interestingly, the cbm gene is genetically linked to a putative type VII secretion system that has been found in Mycobacteria and few other Gram-positive bacteria. When compared with the UA159 type strain, phenotypic characterization of LAR01 revealed increased biofilm formation in the presence of either glucose or sucrose but similar abilities to withstand acid and oxidative stresses. LAR01 was unable to inhibit the growth of Strpetococcus gordonii, which is consistent with the genomic data that indicate absence of mutacins that can kill mitis streptococci. On the other hand, LAR01 effectively inhibited growth of other S. mutans strains, suggesting that it may be specialized to outcompete strains from its own species. In vitro and in vivo studies using mutational and heterologous expression approaches revealed that Cbm is a virulence factor of S. mutans by mediating binding to extracellular matrix proteins and intracellular invasion. Collectively, the whole genome sequence analysis and phenotypic characterization of LAR01 provides new insights on the virulence properties of S. mutans and grants further opportunities to understand the genomic fluidity of this important human pathogen. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd