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

Abstract

As a major etiological agent of human dental caries, <i>Streptococcus mutans</i> resides primarily in biofilms that form on the tooth surfaces, also known as dental plaque. In addition to caries, <i>S. mutans</i> 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 <i>S. mutans</i> 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, <i>S. mutans</i> 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 <i>Escherichia coli</i> and <i>Bacillus subtilis</i>. In addition to sections dedicated to carbohydrate metabolism, biofilm formation, and stress responses, this article discusses newer developments in <i>S. mutans</i> biology research, namely, how <i>S. mutans</i> 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 <i>S. mutans</i> as a species.