Aggregatibacter actinomycetemcomitans | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Pseudomonadota |
Class: | Gammaproteobacteria |
Order: | Pasteurellales |
Family: | Pasteurellaceae |
Genus: | Aggregatibacter |
Species: | A. actinomycetemcomitans |
Binomial name | |
Aggregatibacter actinomycetemcomitans (Klinger 1912) Nørskov-Lauritsen and Kilian 2006 | |
Synonyms | |
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Aggregatibacter actinomycetemcomitans 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. [1] Less frequently, A. actinomycetemcomitans 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.[ citation needed ]
'Bacterium actinomycetem comitans' 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). 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. 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]
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. [8] [9] A systematic screen by RNA-seq and RT-PCR in HK1651 strain (a clinical isolate from an aggressive periodontitis patient), quantified 70 sRNAs and further identified 17 differentially expressed sRNAs during growth phases. [10] Target prediction indicated possibility of sRNA interaction with several virulence genes. [10] This study confirmed the presence of one of previously identified Fur regulated sRNAs JA04 identified in strain HK1651.[ citation needed ]
Gardnerella vaginalis is a species of Gram-variable-staining facultative anaerobic bacteria. The organisms are small non-spore-forming, nonmotile coccobacilli.
The HACEK organisms are a group of fastidious Gram-negative bacteria that are an unusual cause of infective endocarditis, which is an inflammation of the heart due to bacterial infection. HACEK is an abbreviation of the initials of the genera of this group of bacteria: Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella. The HACEK organisms are a normal part of the human microbiota, living in the oral-pharyngeal region.
Haemophilus influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.
Actinomyces is a genus of the Actinomycetia class of bacteria. They all are gram-positive and facultatively anaerobic, growing best under anaerobic conditions. Actinomyces species may form endospores, and while individual bacteria are rod-shaped, Actinomyces colonies form fungus-like branched networks of hyphae. The aspect of these colonies initially led to the incorrect assumption that the organism was a fungus and to the name Actinomyces, "ray fungus".
The Pasteurellaceae comprise a large family of Gram-negative bacteria. Most members live as commensals on mucosal surfaces of birds and mammals, especially in the upper respiratory tract. Pasteurellaceae are typically rod-shaped, and are a notable group of facultative anaerobes. Their biochemical characteristics can be distinguished from the related Enterobacteriaceae by the presence of oxidase, and from most other similar bacteria by the absence of flagella.
Panton–Valentine leukocidin (PVL) is a cytotoxin—one of the β-pore-forming toxins. The presence of PVL is associated with increased virulence of certain strains (isolates) of Staphylococcus aureus. It is present in the majority of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates studied and is the cause of necrotic lesions involving the skin or mucosa, including necrotic hemorrhagic pneumonia. PVL creates pores in the membranes of infected cells. PVL is produced from the genetic material of a bacteriophage that infects Staphylococcus aureus, making it more virulent.
Porphyromonas gingivalis belongs to the phylum Bacteroidota and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar.
Treponema denticola is a Gram-negative, obligate anaerobic, motile and highly proteolytic spirochete bacterium. It is one of four species of oral spirochetes to be reliably cultured, the others being Treponema pectinovorum, Treponema socranskii and Treponema vincentii. T. denticola dwells in a complex and diverse microbial community within the oral cavity and is highly specialized to survive in this environment. T. denticola is associated with the incidence and severity of human periodontal disease. Treponema denticola is one of three bacteria that form the Red Complex, the other two being Porphyromonas gingivalis and Tannerella forsythia. Together they form the major virulent pathogens that cause chronic periodontitis. Having elevated T. denticola levels in the mouth is considered one of the main etiological agents of periodontitis. T. denticola is related to the syphilis-causing obligate human pathogen, Treponema pallidum subsp. pallidum. It has also been isolated from women with bacterial vaginosis.
Actinobacillus is a genus of Gram-negative, nonmotile and non-spore-forming, oval to rod-shaped bacteria occurring as parasites or pathogens in mammals, birds, and reptiles. It is a member of the family Pasteurellaceae. The bacteria are facultatively anaerobic or aerobic, capable of fermenting carbohydrates, and of reducing nitrates. The genomic DNA contains between 40 and 47 mol % guanine plus cytosine.
Prevotella is a genus of Gram-negative bacteria.
Aggregatibacter is a genus in the phylum Pseudomonadota (Bacteria), which contains three species, namely:
Aggregatibacter aphrophilus is a species of bacteria. It is one of the HACEK organisms.
Aggressive periodontitis describes a type of periodontal disease and includes two of the seven classifications of periodontitis as defined by the 1999 classification system:
Actinobacillus pleuropneumoniae, is a Gram-negative, facultative anaerobic, respiratory pathogen found in pigs. It was first reported in 1957, and was formally declared to be the causative agent of porcine pleuropneumonia in 1964. It was reclassified in 1983 after DNA studies showed it was more closely related to A. lignieresii.
Actinomyces viscosus is a human and animal pathogen/pathobiont which colonises the mouths of 70% of adult humans. A. viscosus has a low level of virulence and is often mistaken with other actinomycetes.
Four non-coding small RNAs containing a Fur box-like sequence were identified by bioinformatics analysis in Aggregatibacter actinomycetemcomitansHK1651 called JA01-JA04. The transcription of sRNAs was confirmed by Northern blot. Fur binding was demonstrated to each sRNA promoter, and that transcription of the sRNAs was decreased in presence of iron and increased by iron limitation. JA03 may have the ability to regulate biofilm formation. JA01 is conserved only among A. actinomycetemcomitans. JA02 is present in both A. actinomycetemcomitans and P. multocida. JA 03 and JA04 are most widely conserved and have orthologues across many Pasteurellaceae. HrrF RNA is another Fur-regulated sRNA conserved among the Pasteurcellaceae.
Jørgen Slots is a Danish-born periodontist notable for his contributions to the field of periodontology. He is currently professor of periodontology and microbiology at the Herman Ostrow School of Dentistry of USC, and served as chairman of periodontology from 1991 to 2001.
N-glycosyltransferase is an enzyme in prokaryotes which transfers individual hexoses onto asparagine sidechains in substrate proteins, using a nucleotide-bound intermediary, within the cytoplasm. They are distinct from regular N-glycosylating enzymes, which are oligosaccharyltransferases that transfer pre-assembled oligosaccharides. Both enzyme families however target a shared amino acid sequence asparagine—-any amino acid except proline—serine or threonine (N–x–S/T), with some variations.
Aggregatibacter segnis is a species of bacteria. A. segnis can be cultured on chocolate agar.