Aggregatibacter actinomycetemcomitans
Scientific classification
Kingdom:	Bacteria
Phylum:	Proteobacteria
Class:	Gammaproteobacteria
Order:	Pasteurellales
Family:	Pasteurellaceae
Genus:	Aggregatibacter
Species:	actinomycetemcomitans

Aggregatibacter actinomycetemcomitans is an oral commensal found also in severe infections in the oral cavity, mainly the periodontium. A. actinomycetemcomitans, previously Actinobacillus actinomycetemcomitans, is a gram negative facultative non motile rod. It is also associated with non oral infections. It was first discovered by periodontist Dr. Jorgen Slots, now a University of Southern California faculty member.

Bacterium actinomycetem comitans’ was described by Klinger (1912) as coccobacillary bacteria isolated together with Actinomyces from actinomycotic lesions of man. 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 (Slots & Ting, 1999; Haubek et al., 2001). ^[1]

Contents 1 Nomenclature 2 Importance 3 Virulence Factors 4 A. actinomycetemcomitans Serotypes 5 References

[edit] Nomenclature

Recent studies have shown a phylogenetic similarity of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus, Haemophilus paraphrophilus, and Haemophilus segnis suggesting the new genus Aggregatibacter for them.^[1]

[edit] Importance

It is one of the bacteria which might be implicated in destructive periodontal disease. Although it has been found more frequently in localized aggressive periodontitis,^[2] prevalence in any population is rather high. It has also been isolated from actinomycotic lesions (mixed infection with certain Actinomyces species, in particular Actinomyces israelii). It possesses certain virulence factors that enable it to invade tissues, such as leukotoxin.

[edit] Virulence Factors

- Leukotoxin; kills PMN's and monocytes.

- Cytolethal distending toxin

- Immunosuppression factors that inhibit blastogenesis, antibody production and activate T-suppressor cells

- Inhibition of PMN's functions

- Resistant to complement mediated killing.

[edit] A. actinomycetemcomitans Serotypes

- a strain, for example ATCC 29523, frequently in oral cavity, variable leukotoxin expression.

- b strain Y4, most frequently in localized aggressive periodontitis, leukotoxin expression.

- c strain ATCC 33384, low leukotoxin.

- serotypes d, e

[edit] References

v • d • e Periodontology Tissues of the periodontium and their physiologic entities Alveolar bone · Biologic width · Bundle bone · Cementum · Free gingival margin · Gingiva · Gingival fibers · Gingival sulcus · Junctional epithelium · Mucogingival junction · Periodontal ligament · Sulcular epithelium · Stippling Diagnoses Chronic periodontitis · Localized aggressive periodontitis · Generalized aggressive periodontitis · Periodontitis as a manifestation of systemic disease · Necrotizing periodontal diseases · Abscesses of the periodontium · Combined periodontic-endodontic lesions Pathogenesis A. actinomycetemcomitans · B. forsythus · Capnocytophaga sp. · F. nucleatum · P. gingivalis · P. intermedia · T. denticola Pathologic entities Calculus · Edentulism · Fremitus · Furcation defect · Gingival enlargement · Gingival pocket · Gingivitis · Horizontal bony defect · Linear gingival erythema · Occlusal trauma · Periodontal pocket · Periodontal disease · Periodontitis · Plaque · Recession · Vertical bony defect Diagnosis, treatment planning, prevention and chemotherapeutic agents Brushing · Bleeding on probing · Chlorhexidine gluconate · Enamel matrix derivative · Flossing · Hydrogen peroxide · Mouthwash · Oral hygiene · Tetracycline · Triclosan Periodontal armamentarium Curette · Membrane · Probe · Scaler Conventional therapy Debridement · Scaling and root planing Surgical therapy and periodontal surgery Apically positioned flap · Bone graft · Coronally positioned flap · Crown lengthening · Open flap debridement · Free gingival graft · Gingivectomy · Guided bone regeneration · Guided tissue regeneration · Implant Placement · Lateral pedicle graft · Pocket reduction surgery · Sinus lift · Subepithelial connective tissue graft Important personalities Per-Ingvar Brånemark · Jan Lindhe · Willoughby D. Miller · Carl E. Misch · John Mankey Riggs · Dennis P. Tarnow · James Leon Williams · W. J. Younger Other specialties Endodontology · Orthodontology · Prosthodontology

v • d • e Infectious diseases · Bacterial diseases: Proteobacterial G- (primarily A00–A79, 001–041, 080–109) α Rickettsiales Rickettsiaceae/ (Rickettsioses) Typhus Rickettsia typhi (Murine typhus) · Rickettsia prowazekii (Epidemic typhus) Spotted fever Tick-borne disease Rickettsia rickettsii (Rocky Mountain spotted fever) · Rickettsia conorii (Boutonneuse fever) Other Rickettsia akari (Rickettsialpox) · Orientia tsutsugamushi (Scrub typhus) Anaplasmataceae Ehrlichiosis: Anaplasma phagocytophilum (Human granulocytic anaplasmosis, Anaplasmosis) · Ehrlichia chaffeensis (Human monocytic ehrlichiosis) · Ehrlichia ewingii (Human ewingii ehrlichiosis) Rhizobiales Brucellaceae Brucella abortus (Brucellosis) Bartonellaceae Bartonellosis: Bartonella henselae (Cat-scratch disease) · Bartonella quintana (Trench fever) · either henselae or quintana (Bacillary angiomatosis) · Bartonella bacilliformis (Carrion's disease) β Neisseriales M+ Neisseria meningitidis/meningococcus (Meningococcal disease, Waterhouse-Friderichsen syndrome) M- Neisseria gonorrhoeae/gonococcus (Gonorrhea) ungrouped: Eikenella corrodens/Kingella kingae (HACEK) Burkholderiales Burkholderia pseudomallei (Melioidosis) · Burkholderia mallei (Glanders) · Burkholderia cepacia complex · Bordetella pertussis/Bordetella parapertussis (Pertussis) γ Enterobacteriales (OX-) Lac+ Klebsiella pneumoniae (Rhinoscleroma, Klebsiella pneumonia) · Klebsiella granulomatis (Granuloma inguinale) · Klebsiella oxytoca Escherichia coli: Enterotoxigenic · Enteroinvasive · O157:H7/Enterohemorrhagic (Hemolytic-uremic syndrome) Enterobacter aerogenes/Enterobacter cloacae Slow/weak Serratia marcescens (Serratia infection) · Citrobacter Lac- H2S+ Salmonella enterica (Typhoid fever, Paratyphoid fever, Salmonellosis) H2S- Shigella dysenteriae/sonnei/flexneri/boydii (Shigellosis, Bacillary dysentery) · Proteus mirabilis/Proteus vulgaris · Yersinia pestis (Plague/Bubonic plague) · Yersinia enterocolitica · Yersinia pseudotuberculosis Pasteurellales Haemophilus: H. influenzae (Haemophilus meningitis, Brazilian purpuric fever) · H. ducreyi (Chancroid) H. parainfluenzae (HACEK) Pasteurella multocida (Pasteurellosis) · Actinobacillus (Actinobacillosis) Aggregatibacter actinomycetemcomitans (HACEK) Legionellales Legionella pneumophila/Legionella longbeachae (Legionellosis) · Coxiella burnetii (Q fever) Thiotrichales Francisella tularensis (Tularemia) Vibrionales Vibrio cholerae (Cholera) · Vibrio vulnificus · Vibrio parahaemolyticus · Vibrio alginolyticus · Plesiomonas shigelloides Pseudomonadales Pseudomonas aeruginosa (Pseudomonas infection) · Moraxella catarrhalis · Acinetobacter baumannii Xanthomonadales Stenotrophomonas maltophilia Cardiobacteriales Cardiobacterium hominis (HACEK) ε Campylobacterales Campylobacter jejuni (Campylobacteriosis, Guillain-Barré syndrome) · Helicobacter pylori (Peptic ulcer, MALT lymphoma)