Aggregatibacter actinomycetemcomitans

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Aggregatibacter actinomycetemcomitans
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Pasteurellales
Family: Pasteurellaceae
Genus: Aggregatibacter
Species: actinomycetemcomitans
Binomial name
Aggregatibacter actinomycetemcomitans
(Klinger, 1912)

Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) is a Gram-negative, facultative anaerobe, non-motile 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.[1] Less frequently, A. actinomycetemcomitans is associated with non-oral 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 actinomycetem comitans' was first described by Klinger (1912) as coccobacillary bacteria isolated together 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). The species has attracted attention because of its association with localized aggressive periodontitis.[2]


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.[2]


It is one of the bacteria that might be implicated in destructive periodontal disease, although it has been found more frequently in localized aggressive periodontitis,[3] prevalence in any population is rather high. It has also been isolated from actinomycotic lesions (mixed infection with certain Actinomyces species, in particular A. israelii). It possesses certain virulence factors that enable it to invade tissues, such as the pore-forming toxin leukotoxin A (LtxA), it has also been isolated from women with bacterial vaginosis and as an etiologic agent in endocarditis.[4] The pore-forming toxin LtxA of A. actinomycetemcomitans may be a trigger of the autoimmune disease rheumatoid arthritis due to its ability to stimulate protein citrullination, a post-translational protein modification targeted by autoantibodies in this disease.[5][6]

Virulence factors[edit]

A. actinomycetemcomitans serotypes[edit]

  • a strain, for example ATCC 29523, frequently in oral cavity, variable leukotoxin expression
  • b strain Y4, most frequently in localized aggressive periodontitis, high leukotoxin expression
  • c strain ATCC 33384, low leukotoxin expression
  • serotypes d, e, f, g
  • within each serotype, leukotoxin expression can be highly variable between strains

See also[edit]


  1. ^ Henderson B, Ward JM, Ready D (2010). "Aggregatibacter (Actinobacillus) actinomycetemcomitans: a triple A* periodontopathogen?". Periodontology 2000. 54 (1): 78–105. doi:10.1111/j.1600-0757.2009.00331.x. PMID 20712635. 
  2. ^ a b Nørskov-Lauritsen N; Kilian M (September 2006). "Reclassification of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Haemophilus paraphrophilus and Haemophilus segnis as 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". Int. J. Syst. Evol. Microbiol. 56 (Pt 9): 2135–46. doi:10.1099/ijs.0.64207-0. PMID 16957111. 
  3. ^ Slots J (January 1976). "The predominant cultivable organisms in juvenile periodontitis". Scand J Dent Res. 84 (1): 1–10. doi:10.1111/j.1600-0722.1976.tb00454.x. PMID 1061986. 
  4. ^ Africa, Charlene; Nel, Janske; Stemmet, Megan (2014). "Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation". International Journal of Environmental Research and Public Health. 11 (7): 6979–7000. doi:10.3390/ijerph110706979. ISSN 1660-4601. PMC 4113856Freely accessible. PMID 25014248. 
  5. ^ Konig MF, Abusleme L, Reinholdt J, Palmer RJ, Teles RP, Sampson K, Rosen A, Nigrovic PA, Sokolove J, Giles JT, Moutsopoulos NM, Andrade F (2016). "Aggregatibacter actinomycetemcomitans-induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis". Science Translational Medicine. 8 (369): 369ra176. doi:10.1126/scitranslmed.aaj1921. PMC 5384717Freely accessible. PMID 27974664. 
  6. ^ Abbasi, Jennifer (2017-03-28). "To Prevent Rheumatoid Arthritis, Look Past the Joints to the Gums". JAMA. 317 (12): 1201–1202. doi:10.1001/jama.2017.0764. 

External links[edit]