General Information: Aggregatibacter actinomycetemcomitans D11S-1 was recovered from a subject with aggressive periodontitis. Aggregatibacter actinomycetemcomitans, previously Actinobacillus actinomycetemcomitans typically resides in the oral cavity of humans and animals and can cause a number of diseases. The bacterium, along with 3 other organisms, is the main culprit in periodontis, which results in devastation to the bone supporting the teeth. Adherence to oral surfaces is controlled through the tad (tight adherence) locus, which may express proteins that are involved in type IV secretion.