<unk>  is a Gram-negative, facultative anaerobe, nonmotile bacterium that is often found in association with localized aggressive periodontitis, a severe infection of the periodontium. It is also suspected to be involved in chronic periodontitis. Less frequently, A.<unk>  is associated with nonoral infections such as endocarditis. Its role in aggressive periodontitis was first discovered by Danish-born periodontist Jørgen Slots, a professor of dentistry and microbiology at the University of Southern California School of Dentistry. 'Bacterium<unk> ' was first described by Klinger (1912) as coccobacillary bacteria isolated with Actinomyces from actinomycotic lesions in humans. It was reclassified as Actinobacillus<unk>  by Topley & Wilson (1929) and as Haemophilus<unk>  by Potts et al. (1985). The species has attracted attention because of its association with localized aggressive periodontitis.
Aggregatibacter actinomycetemcomitans
Entamoeba gingivalis
Neisseria mucosa
Haemophilus ducreyi
Mansonella perstans
Porphyromonas gingivalis
Tannerella forsythia
Veillonella parvula