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Periodontology 2000 Oct 2010
Review
Topics: Aggregatibacter actinomycetemcomitans; Aggressive Periodontitis; Alveolar Bone Loss; Animals; Bacterial Adhesion; Bacterial Secretion Systems; Bacterial Toxins; Bacterial Typing Techniques; Epithelial Cells; Genome, Bacterial; Humans; Iron; Virulence
PubMed: 20712635
DOI: 10.1111/j.1600-0757.2009.00331.x -
Proceedings of the National Academy of... Oct 2019is associated with aggressive periodontitis resulting in premature tooth loss in adolescents. Tooth adherence and biofilm persistence are prerequisites for survival in...
is associated with aggressive periodontitis resulting in premature tooth loss in adolescents. Tooth adherence and biofilm persistence are prerequisites for survival in the oral domain. Here, using a rhesus monkey model, 16S rRNA sequencing, and weighted network analysis, we assessed colonization of variants and ascertained microbial interactions in biofilm communities. Variants in leukotoxin () were created, labeled, inoculated, and compared with their progenitor strain for in vivo colonization. Samples of tooth-related plaque were assessed for colonization at baseline and after debridement and inoculation of labeled strains. Null, minimal, and hyper-Ltx-producing strains were created and assessed for hydroxyapatite binding and biofilm formation in vitro. Ltx-hyperproducing strains colonized with greater prevalence and at higher levels than wild type or mutants ( = 0.05). Indigenous and inoculated strains that attached were associated with lactate-producing species (i.e., Leptotrichia, Abiotrophia, and Streptoccocci). was found at 0.13% of the total flora at baseline and at 0.05% 4 wk after inoculation. In vivo data were supported by in vitro results. We conclude that hyper-Ltx production affords these strains with an attachment advantage providing a foothold for competition with members of the indigenous microbiota. Increased attachment can be linked to gene expression and up-regulation of adherence-associated genes. Growth of attached in vivo was enhanced by lactate availability due to consorting species. These associations provide with the constituents required for its colonization and survival in the complex and competitive oral environment.
Topics: Aggregatibacter actinomycetemcomitans; Animals; Bacterial Adhesion; Biofilms; Durapatite; Exotoxins; Lactic Acid; Macaca mulatta; Male; Microbiota; Mouth; Periodontitis
PubMed: 31611409
DOI: 10.1073/pnas.1905238116 -
Revista Chilena de Infectologia :... Dec 2011
Topics: Aggregatibacter actinomycetemcomitans
PubMed: 22286682
DOI: No ID Found -
Periodontology 2000 Jun 2020Atherosclerosis is central to the pathology of cardiovascular diseases, a group of diseases in which arteries become occluded with atheromas that may rupture, leading to... (Review)
Review
Atherosclerosis is central to the pathology of cardiovascular diseases, a group of diseases in which arteries become occluded with atheromas that may rupture, leading to different cardiovascular events, such as myocardial infarction or ischemic stroke. There is a large body of epidemiologic and animal model evidence associating periodontitis with atherosclerotic disease, and many potential mechanisms linking these diseases have been elucidated. This chapter will update knowledge on these mechanisms, which generally fall into 2 categories: microbial invasion and infection of atheromas; and inflammatory and immunologic. With respect to the invasion and infection of atheromas, it is well established that organisms from the subgingival biofilm can enter the circulation and lodge in most distant tissues. Bacteremias resulting from oral interventions, and even oral hygiene activities, are well documented. More recently, indirect routes of entry of oral organisms (via phagocytes or dendritic cells) have been described for many oral organisms, into many tissues. Such organisms include the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, and Fusobacterium nucleatum. Intracellular survival of these organisms with dissemination to distant sites (The Trojan Horse approach) has been described. Their relative contribution to atheroma formation and progression has been studied mainly in experimental research, with results demonstrating that these organisms can invade endothelial cells and phagocytic cells within the atheroma, leading to pathogenic changes and progression of the atheroma lesion. The second category of mechanisms potentially linking periodontitis to atherosclerosis includes the dumping of inflammatory mediators originating from periodontal lesions into the systemic circulation. These inflammatory mediators, such as C-reactive protein, matrix metalloproteinases, fibrinogen, and other hemostatic factors, would further accelerate atheroma formation and progression, mainly through oxidative stress and inflammatory dysfunction. Moreover, direct effects on lipid oxidation have also been described. In summary, the evidence supports the concept that periodontitis enhances the levels of systemic mediators of inflammation that are risk factors for atherosclerotic diseases.
Topics: Aggregatibacter actinomycetemcomitans; Atherosclerosis; Endothelial Cells; Humans; Periodontitis; Porphyromonas gingivalis; Prevotella intermedia
PubMed: 32385879
DOI: 10.1111/prd.12304 -
International Dental Journal Feb 2024The aim of this work was to explore the association between Aggregatibacter actinomycetemcomitans (A actinomycetemcomitans) infection and disease activity amongst those...
OBJECTIVE
The aim of this work was to explore the association between Aggregatibacter actinomycetemcomitans (A actinomycetemcomitans) infection and disease activity amongst those with rheumatoid arthritis (RA) with or without periodontitis (PD) in a Chinese population.
METHODS
A case-control study was conducted from November 2017 to March 2019. The correlation coefficients between A actinomycetemcomitans positivity and RA-related examination indicators as well as periodontal examination parameters were calculated by using the Spearman correlation analysis.
RESULTS
A total of 115 patients with RA were recruited: 67 patients with RA only and 48 with RA + PD. The percentage of A actinomycetemcomitans positivity was significantly higher in the RA + PD group compared with the RA-only group (P = .007 for positive percentage; P = .020 for percentage of A actinomycetemcomitans positivity in the total oral microbiome). Furthermore, RA-related measures such as Disease Activity Score 28, rheumatoid factor, anticyclic citrullinated peptide, and anticitrullinated protein antibodies were all positively correlated with the percentage of A actinomycetemcomitans positivity (P range: .002∼.041). In addition, significant correlations were observed amongst A actinomycetemcomitans positivity and probing pocket depth (P = .027) and gingival index (P = .043), whereas null correlations were found amongst the percentage of A actinomycetemcomitans positivity and plaque index (P = .344), clinical attachment loss (P = .217), and bleeding on probing (P = .710).
CONCLUSIONS
A actinomycetemcomitans infection may be related to the development of PD amongst patients with RA.
Topics: Humans; Aggregatibacter actinomycetemcomitans; Case-Control Studies; Periodontitis; Arthritis, Rheumatoid; Periodontal Attachment Loss
PubMed: 37517936
DOI: 10.1016/j.identj.2023.06.011 -
Journal of Periodontology Dec 2020Aggressive periodontitis is characterized by the early-onset and rapid progression of periodontal destruction and is closely associated with Aggregatibacter...
BACKGROUND
Aggressive periodontitis is characterized by the early-onset and rapid progression of periodontal destruction and is closely associated with Aggregatibacter actinomycetemcomitans. Autophagy is a conserved process that is critical for removing damaged proteins, organelles, and even intracellular pathogens. Therefore, this study examined whether A. actinomycetemcomitans induces autophagy. In addition, the relationship among autophagy, bacterial internalization, and inflammatory molecules in periodontal aggressive inflammation was analyzed.
METHODS
The expression of autophagy-related proteins in human gingival tissue and THP-1 cells was assessed by Western blot analysis. The formation of light chain 3 (LC3) puncta was examined by confocal microscopy. The degree of bacterial internalization into the cells was determined by the viable cell count. Phagocytosis and reactive oxygen species (ROS) production were measured using confocal microscopy and flow cytometry.
RESULTS
When macrophages were infected with live A. actinomycetemcomitans, the autophagy influx was activated by the increase in LC3-II, autophagy-related gene 5/12, and Beclin-1 expression through the Toll-like receptors and extracellular signal-regulated kinase signaling pathways. The inhibition of A. actinomycetemcomitans-induced autophagy suppressed bacterial internalization via phagocytosis into the macrophages and increased interleukin (IL)-1β production. Moreover, treatment with an ROS inhibitor inhibited these enhanced inflammatory responses.
CONCLUSIONS
A. actinomycetemcomitans-induced autophagy promotes bacterial internalization by phagocytosis, which restricts the excessive inflammatory response by downregulating IL-1β and ROS production in macrophages. Thus, A. actinomycetemcomitans-induced autophagy and its role in regulating the inflammatory response may play an important role in the aggressive periodontal inflammatory process, and be a target for the development of new periodontal therapies.
Topics: Aggregatibacter actinomycetemcomitans; Autophagy; Humans; Inflammation; Macrophages; Phagocytosis
PubMed: 32170963
DOI: 10.1002/JPER.19-0639 -
Scientific Reports Mar 2021This study aimed to focus on the simultaneous use of antimicrobial photodynamic therapy (aPDT) and sonodynamic antimicrobial chemotherapy (SACT), which is called...
This study aimed to focus on the simultaneous use of antimicrobial photodynamic therapy (aPDT) and sonodynamic antimicrobial chemotherapy (SACT), which is called photo-sonodynamic antimicrobial chemotherapy (PSACT) to attenuate the virulence of Aggregatibacter actinomycetemcomitans. Following the synthesis of Curcumin-decorated nanophytosomes (Cur-NPhs) as a novel photo-sonosensitizer, its particle size, polydispersity, ζ-potential surface morphology, physical stability, drug release, and entrapment efficiency were determined. In the Cur-NPhs-PSACT, the antimicrobial activities of Cur-NPhs against A. actinomycetemcomitans were investigated using cell viability, biofilm killing/degradation, metabolic activity, expression of quorum-sensing-associated qseB and qseC genes, and biofilm-associated rcpA gene under blue laser irradiation plus ultrasonic waves. Characterization tests showed the presence of a sphere-shaped vesicle and the self-closed structure of Cur-NPhs, resulting in a high drug-loading content and encapsulation efficiency. However, the antimicrobial effect of Cur-NPhs-PSACT was dose-dependent, PSACT using the high concentrations of Cur-NPhs (50 × 10 g/L) showed significant reductions (P < 0.05) in cell viability (13.6 log CFU/mL), biofilm killing/degradation (65%), metabolic activity (89.6%,), and mRNA levels of virulence determinant genes (qseB; 9.8-fold, qseC; 10.2-fold, and recA; 10.2-fold). This study concludes that the Cur-NPhs-PSACT had antimicrobial activities against A. actinomycetemcomitans by downregulating the expression of virulence genes, and may attenuate this bacterium that decreases periodontal disease severity in patients.
Topics: Aggregatibacter actinomycetemcomitans; Anti-Infective Agents; Biofilms; Curcumin; Nanoparticles; Photochemotherapy; Photosensitizing Agents; Virulence
PubMed: 33727630
DOI: 10.1038/s41598-021-85437-6 -
Microbiology Spectrum Feb 2023Aggregatibacter actinomycetemcomitans () is a Gram-negative bacterial pathogen associated with periodontitis and nonoral diseases like rheumatoid arthritis and...
Aggregatibacter actinomycetemcomitans () is a Gram-negative bacterial pathogen associated with periodontitis and nonoral diseases like rheumatoid arthritis and Alzheimer´s disease. isolates with the serotypes a, b, and c are globally most prevalent. Importantly, isolates displaying these serotypes have different clinical presentations. While serotype b isolates are predominant in severe periodontitis, serotypes a and c are generally encountered in mild periodontitis or healthy individuals. It is currently unknown how these differences are reflected in the overall secretion of virulence factors. Therefore, this study was aimed at a comparative analysis of exoproteomes from different clinical isolates with serotypes a, b, or c by mass spectrometry, and a subsequent correlation of the recorded exoproteome profiles with virulence. Overall, we identified 425 extracellular proteins. Significant differences in the exoproteome composition of isolates with different serotypes were observed in terms of protein identification and abundance. In particular, serotype a isolates presented more extracellular proteins than serotype b or c isolates. These differences are mirrored in their virulence in infection models based on human salivary gland epithelial cells and neutrophils. Remarkably, serotype a isolates displayed stronger adhesive capabilities and induced more lysis of epithelial cells and neutrophils than serotype b or c isolates. Conversely, serotype c isolates showed relatively low leukotoxicity, while provoking NETosis to similar extents as serotype a and b isolates. Altogether, we conclude that the differential virulence presentation by isolates with the dominant serotypes a, b, or c can be explained by their exoproteome heterogeneity. Periodontitis is an inflammatory disease that causes progressive destruction of alveolar bone and supporting tissues around the teeth, ultimately resulting in tooth loss. The bacterium Aggregatibacter actinomycetemcomitans () is a prevalent causative agent of periodontitis, but this oral pathogen is also associated with serious extraoral diseases like rheumatoid arthritis and Alzheimer's disease. Clinical isolates are usually distinguished by serotyping, because of known serotype-specific differences in virulence. with serotype b is associated with aggressive forms of periodontitis, while isolates with serotypes a or c are usually encountered in cases of mild periodontitis or healthy individuals. The molecular basis for these differences in virulence was so far unknown. In the present study, we pinpoint serotype-specific differences in virulence factor production by clinical isolates. We consider these findings important, because they provide new leads for future preventive or therapeutic approaches to fight periodontitis and associated morbidities.
Topics: Humans; Serogroup; Aggregatibacter actinomycetemcomitans; Virulence; Alzheimer Disease; Periodontitis; Serotyping; Virulence Factors
PubMed: 36541765
DOI: 10.1128/spectrum.03298-22 -
Clinical Microbiology Reviews Apr 2014The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or... (Review)
Review
The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or predominant host specificity for humans. Haemophilus influenzae and some of the other Haemophilus species are commonly encountered in the clinical microbiology laboratory and demonstrate a wide range of pathogenicity, from life-threatening invasive disease to respiratory infections to a nonpathogenic, commensal lifestyle. New species of Haemophilus have been described (Haemophilus pittmaniae and Haemophilus sputorum), and the new genus Aggregatibacter was created to accommodate some former Haemophilus and Actinobacillus species (Aggregatibacter aphrophilus, Aggregatibacter segnis, and Aggregatibacter actinomycetemcomitans). Aggregatibacter species are now a dominant etiology of infective endocarditis caused by fastidious organisms (HACEK endocarditis), and A. aphrophilus has emerged as an important cause of brain abscesses. Correct identification of Haemophilus and Aggregatibacter species based on phenotypic characterization can be challenging. It has become clear that 15 to 20% of presumptive H. influenzae isolates from the respiratory tracts of healthy individuals do not belong to this species but represent nonhemolytic variants of Haemophilus haemolyticus. Due to the limited pathogenicity of H. haemolyticus, the proportion of misidentified strains may be lower in clinical samples, but even among invasive strains, a misidentification rate of 0.5 to 2% can be found. Several methods have been investigated for differentiation of H. influenzae from its less pathogenic relatives, but a simple method for reliable discrimination is not available. With the implementation of identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry, the more rarely encountered species of Haemophilus and Aggregatibacter will increasingly be identified in clinical microbiology practice. However, identification of some strains will still be problematic, necessitating DNA sequencing of multiple housekeeping gene fragments or full-length 16S rRNA genes.
Topics: Aggregatibacter; Bacteriological Techniques; Haemophilus; Haemophilus Infections; Host Specificity; Humans; Molecular Diagnostic Techniques; Pasteurellaceae Infections; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 24696434
DOI: 10.1128/CMR.00103-13 -
Methods in Molecular Biology (Clifton,... 2021Aggregatibacter actinomycetemcomitans is frequently isolated from localized aggressive periodontitis and periodontitis associated with systemic diseases. A....
Aggregatibacter actinomycetemcomitans is frequently isolated from localized aggressive periodontitis and periodontitis associated with systemic diseases. A. actinomycetemcomitans produces a leukotoxin, which induces apoptosis in human leukocytes. The leukotoxin expression is dependent on the upstream sequence, likely including the promoter, of the gene encoding leukotoxin; strains with the truncated/short upstream sequence express more leukotoxin than strains with the general/long upstream. This chapter addresses the determination of the type of the leukotoxin promoter by PCR analysis, and detection of the apoptosis in the coculture of human monocyte cell line (THP-1) with A. actinomycetemcomitans by the DNA ladder formation, membrane perturbation, and lactate dehydrogenase release.
Topics: Aggregatibacter actinomycetemcomitans; Apoptosis; Cell Line; Coculture Techniques; Exotoxins; Humans; Leukocytes; Pasteurellaceae Infections; Polymerase Chain Reaction; Promoter Regions, Genetic; Virulence
PubMed: 32815139
DOI: 10.1007/978-1-0716-0939-2_18