Nomenclature
- Aggregatibacter actinomycetemcomitans was first described by Klinger (1912) as coccobacillary bacteria isolated with Actinomyces from actinomycotic lesions in humans.
- It was reclassified as Actinobacillus actinomycetemcomitans by Topley & Wilson (1929) and as Haemophilus actinomycetemcomitans by Potts et al. (1985).
- Recent studies have shown a phylogenetic similarity of A. actinomycetemcomitans and Haemophilus aphrophilus, H. paraphrophilus, and H. segnis, suggesting the new genus Aggregatibacter for them.

Importance
- A. actinomycetemcomitans is one of the bacteria that might be implicated in destructive periodontal disease.
- It has been found more frequently in localized aggressive periodontitis, but its prevalence in any population is rather high.
- It has been isolated from actinomycotic lesions and possesses certain virulence factors that enable it to invade tissues, such as the pore-forming toxin leukotoxin A.
- It has also been isolated from women with bacterial vaginosis and as an etiologic agent in endocarditis.
- The pore-forming toxin LtxA of A. actinomycetemcomitans may be a trigger of the autoimmune disease rheumatoid arthritis.

See also
- List of bacterial vaginosis microbiota
- Oral microbiology

References
- Henderson B, Ward JM, Ready D (October 2010). Aggregatibacter (Actinobacillus) actinomycetemcomitans: a triple A* periodontopathogen?
- Nørskov-Lauritsen N, Kilian M (September 2006). Reclassification of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Haemophilus paraphrophilus, and Haemophilus segnis Aggregatibacter actinomycetemcomitans gen. nov., comb. nov., Aggregatibacter aphrophilus comb. nov. and Aggregatibacter segnis comb. nov., and emended description of Aggregatibacter aphrophilus to include V factor-dependent and V factor-independent isolates.
- Slots J (January 1976). The predominant cultivable organisms in juvenile periodontitis.
- Africa CW, Nel J, Stemmet M (July 2014). Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonization.
- Konig MF, Abusleme L, Reinholdt J, Palmer RJ, Teles RP, Sampson K, Rosen A, Nigrovic PA, Sokolove J, Giles JT, Moutsopoulos NM, Andrade F (December 2016). Aggregatibacter actinomycetemcomitans-induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis.

Additional Studies
- In bacteria, small RNAs are involved in gene regulation.
- Jorth et al. identified 9 sRNA by Northern blotting from computer-predicted candidates in strain VT1169 and 202 sRNA by RNA seq in strain 624.
- A systematic screen by RNA-seq and RT-PCR in HK1651 strain quantified 70 sRNAs and further identified 17 differentially expressed sRNAs during growth phases.
- Target prediction indicated the possibility of sRNA interaction with several virulence genes.
- This study confirmed the presence of one of the previously identified Fur regulated sRNAs JA04 identified in strain HK1651.