The Biology of <i>Streptococcus mutans</i>

<jats:title>ABSTRACT</jats:title> <jats:p> As a major etiological agent of human dental caries, <jats:italic>Streptococcus mutans</jats:italic> resides primarily in biofilms that form on the tooth surfaces, also known as dental plaque. In addition to caries, <jats:italic>S. mutans</jats:italic> is responsible for cases of infective endocarditis with a subset of strains being indirectly implicated with the onset of additional extraoral pathologies. During the past 4 decades, functional studies of <jats:italic>S. mutans</jats:italic> have focused on understanding the molecular mechanisms the organism employs to form robust biofilms on tooth surfaces, to rapidly metabolize a wide variety of carbohydrates obtained from the host diet, and to survive numerous (and frequent) environmental challenges encountered in oral biofilms. In these areas of research, <jats:italic>S. mutans</jats:italic> has served as a model organism for ground-breaking new discoveries that have, at times, challenged long-standing dogmas based on bacterial paradigms such as <jats:italic>Escherichia coli</jats:italic> and <jats:italic>Bacillus subtilis</jats:italic> . In addition to sections dedicated to carbohydrate metabolism, biofilm formation, and stress responses, this article discusses newer developments in <jats:italic>S. mutans</jats:italic> biology research, namely, how <jats:italic>S. mutans</jats:italic> interspecies and cross-kingdom interactions dictate the development and pathogenic potential of oral biofilms and how next-generation sequencing technologies have led to a much better understanding of the physiology and diversity of <jats:italic>S. mutans</jats:italic> as a species. </jats:p>