Latest News on Aggregatibacter Research: Jan – 2020

Aggregatibacter actinomycetemcomitans Leukotoxin: from Threat to Therapy

Aggregatibacter actinomycetemcomitans may be a Gram-negative bacterium that colonizes the human mouth and is that the causative agent for localized aggressive periodontitis (LAP), an aggressive sort of periodontitis that happens in adolescents. A. actinomycetemcomitans secretes a protein toxin, leukotoxin (LtxA), which helps the bacterium evade the host immune reaction during infection. LtxA may be a membrane-active toxin that specifically targets white blood cells (WBCs). during this review, we discuss recent developments during this field, including the identification and characterization of genes and proteins involved in secretion, regulation of LtxA, biosynthesis, newly described activities of LtxA, and the way LtxA could also be used as a therapy for the treatment of diseases. [1]

Aggregatibacter actinomycetemcomitans–induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis

Although atrophic arthritis is an autoimmune disorder , scientists have long suspected that bacterial infections (and especially , periodontal infections) may play a task in its pathogenesis. Konig et al. now demonstrate that a specific periodontal pathogen called Aggregatibacter actinomycetemcomitans (Aa) induces changes in neutrophil function, including hypercitrullination of host proteins, an abnormality that’s also observed within the joints of patients with atrophic arthritis . Moreover, the effect of HLA-DRB1, an allele related to increased risk of atrophic arthritis , was only observed in patients exposed to Aa, suggesting the likelihood of eventually using these results to spot and possibly even treat high-risk patients. [2]

Aggregatibacter actinomycetemcomitans and Its Relationship to Initiation of Localized Aggressive Periodontitis: Longitudinal Cohort Study of Initially Healthy Adolescents

Aggregatibacter actinomycetemcomitans is usually related to localized aggressive periodontitis (LAP); however, longitudinal cohort studies relating A. actinomycetemcomitans to initiation of LAP haven’t been reported. A periodontal assessment was performed on 1,075 primarily African-American and Hispanic schoolchildren, ages 11 to 17 years. Samples were taken from each child for A. actinomycetemcomitans. A cohort of 96 students was established that included a test group of 38 A. actinomycetemcomitans-positive students (36 periodontally healthy and a couple of with periodontal pockets) and 58 healthy A. actinomycetemcomitans-negative controls. All clinical and microbiological procedures were repeated at 6-month intervals. [3]

Diversity patterns of bacteriophages infecting Aggregatibacter and Haemophilus species across clades and niches

Aggregatibacter and Haemophilus species are relevant human commensals and opportunistic pathogens. Consequently, their bacteriophages may have significant impact on human microbial ecology and pathologies. Our aim was to reveal the prevalence and variety of bacteriophages infecting Aggregatibacter and Haemophilus species that colonize the physical body . Genome mining with comparative genomics, screening of clinical isolates, and profiling of metagenomes allowed characterization of 346 phages grouped in 52 clusters and 18 superclusters. [4]

Prevalence of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum among Clinical Orthodontic and Non-Orthodontic Saliva Samples

Objectives: The oral flora may be a complex ecosystem characterized by numerous bacterial species and changes to the amount of those bacteria in health, disease, and dental treatments like orthodontics. Although some studies have documented changes in periodontal pathogen burden during treatment using saliva, most have focused on traditional cariogenic bacteria and a few periodontal pathogens, like Porphyromonas gingivalis or Fusobacterium nucleatum– far fewer have focused on Aggregatibacter actinomycetemcomitans – commonly related to aggressive periodontitis. Therefore, the most objective of this study was to guage the prevalence of this organism among orthodontic and non-orthodontic patients from a public school of dentistry clinic. [5]

Reference

[1] Kachlany, S.C., 2010. Aggregatibacter actinomycetemcomitans leukotoxin: from threat to therapy. Journal of dental research, 89(6), (Web Link)

[2] Konig, M.F., Abusleme, L., Reinholdt, J., Palmer, R.J., Teles, R.P., Sampson, K., Rosen, A., Nigrovic, P.A., Sokolove, J., Giles, J.T. and Moutsopoulos, N.M., 2016. Aggregatibacter actinomycetemcomitans–induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis. Science translational medicine, 8(369), (Web Link)

[3] Fine, D.H., Markowitz, K., Furgang, D., Fairlie, K., Ferrandiz, J., Nasri, C., McKiernan, M. and Gunsolley, J., 2007. Aggregatibacter actinomycetemcomitans and its relationship to initiation of localized aggressive periodontitis: longitudinal cohort study of initially healthy adolescents. Journal of clinical microbiology, 45(12), (Web Link)

[4] Diversity patterns of bacteriophages infecting Aggregatibacter and Haemophilus species across clades and niches
Szymon P. Szafrański, Mogens Kilian, Ines Yang, Gesa Bei der Wieden, Andreas Winkel, Jan Hegermann & Meike Stiesch
The ISME Journal volume 13, (Web Link)

[5] Klingler, J., Shen, C. and Kingsley, K. (2018) “Prevalence of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum among Clinical Orthodontic and Non-Orthodontic Saliva Samples”, Journal of Advances in Microbiology, 11(3), (Web Link)

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