Which bacteria is known for causing dental caries?

Streptococcus mutans is the bacterium primarily associated with the formation of dental caries, commonly known as tooth decay. This organism is a gram-positive cocci that thrives in the oral cavity and is a key contributor to the demineralization of tooth enamel. S. mutans metabolizes sugars from food and, during the process, produces acid as a byproduct. This acid accumulation leads to a decreased pH in the oral environment, promoting the dissolution of the mineral structure of the teeth and ultimately resulting in caries.

In contrast, other listed bacteria do not play a direct role in dental caries. Salmonella enterica primarily causes gastrointestinal diseases, Mycobacterium leprae is responsible for leprosy, affecting the skin and nerves, and Escherichia coli, while sometimes causing urinary tract infections or foodborne illnesses, is not associated with dental decay. Therefore, the unique ability of Streptococcus mutans to thrive in the dental biofilm and produce acid from dietary carbohydrates is what makes it the leading cause of dental caries.