Actinomyces naeslundii

Actinomyces naeslundii is a Gram-positive, rod-shaped bacterium that occupies the oral cavity. The species has been implicated in periodontal disease, secondary enamel caries and primary root caries. These bacteria are also associated with good oral health. They are some of the first bacteria to occupy the oral cavity and colonize the tooth's surface. It has also been isolated from women with bacterial vaginosis.