Final answer:
Streptococcus species, excluding Streptococcus salivarius and Actinomyces that feed on sugars and carbon, are typically nonpyogenic colonizers within the human oral cavity, some of which may contribute to dental caries.
Step-by-step explanation:
Streptococcus which feeds on sugars and carbon, except for Streptococcus salivarius and Actinomyces, are considered nonpyogenic colonizers.
These bacteria reside within the human oral cavity and play a role in dental health, with species such as Streptococcus mutans being implicated in the development of dental caries due to their metabolic activities.
Unlike pyogenic streptococci associated with pus production and pathogenesis, such as S. pyogenes, nonpyogenic species do not belong to any of the Lancefield groups and mostly act as commensals, which are part of the normal flora.