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Background: This study determined the prevalence of aggressive (molar‐incisor pattern) (Ag/MI) periodontitis and assessed the associated subgingival bacterial‐herpesvirus microbiota in Pueblo Indian adolescents in the southwestern United States. Methods: The study included 240 Pueblo Indian adolescents, aged 13–20 years old, residing in three Rio Grande River villages in New Mexico and the Hopi Pueblo reservation in Arizona. Adolescents with Ag/MI periodontitis or periodontal health provided subgingival samples for culture of bacterial pathogens and for polymerase chain reaction detection of periodontal herpesviruses. Results: Ag/MI periodontitis was detected in 22 (9.2%) Pueblo Indian adolescents, with 21 exhibiting a localized molar‐incisor breakdown pattern. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and other red/orange complex bacterial pathogens predominated in Ag/MI periodontitis, whereas periodontal health yielded mainly viridans streptococci and Actinomyces species. Periodontal herpesviruses demonstrated a 3.5 odds ratio relationship with Ag/MI periodontitis. The only adolescent with generalized Ag/MI periodontitis harbored viral co‐infection by cytomegalovirus plus Epstein–Barr virus Type 1, in addition to A. actinomycetemcomitans, P. gingivalis, and several other periodontopathic bacteria. Conclusions: Pueblo Indian adolescents showed an unusually high prevalence of early‐age Ag/MI periodontitis predominated by periodontopathic bacteria and herpesviruses suspected to be major etiologic agents of the disease. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Aggregatibacter spp. is a rare cause for cardiac device infections. Due to limited data, the management of Aggregatibacter spp. device infections is not clearly defined but should always involve device removal and prolonged intravenous antibiotics. [ABSTRACT FROM AUTHOR]

Aim: Evidence suggests that translocation of oral pathogens through the oral-gut axis may induce intestinal dysbiosis. This study aimed to evaluate the impact of a highly leukotoxic Aggregatibacter actinomycetemcomitans (Aa) strain on the gut microbiota, intestinal mucosal integrity and immune system in healthy mice., Methods: Eight-week-old male C57BL6 mice were divided into control (n = 16) and JP2 groups (n = 19), which received intragastric gavage with PBS and with a suspension of Aa JP2 (HK921), respectively, twice a week for 4 weeks. Colonic lamina propria, fecal material, serum, gingival tissues, and mandibles were obtained for analyses of leukocyte populations, inflammatory mediators, mucosal integrity, alveolar bone loss, and gut microbiota. Differences between groups for these parameters were examined by non-parametric tests., Results: The gut microbial richness and the number of colonic macrophages, neutrophils, and monocytes were significantly lower in Aa JP2-infected mice than in controls (p < .05). In contrast, infected animals showed higher abundance of Clostridiaceae, Lactobacillus taiwanensis, Helicobacter rodentium, higher levels of IL-6 expression in colonic tissues, and higher splenic MPO activity than controls (p < .05). No differences in tight junction expression, serum endotoxin levels, and colonic inflammatory cytokines were observed between groups. Infected animals presented also slightly more alveolar bone loss and gingival IL-6 levels than controls (p < .05)., Conclusion: Based on this model, intragastric administration of Aa JP2 is associated with changes in the gut ecosystem of healthy hosts, characterized by less live/recruited myeloid cells, enrichment of the gut microbiota with pathobionts and decrease in commensals. Negligible levels of colonic pro-inflammatory cytokines, and no signs of mucosal barrier disruption were related to these changes., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Polyamines are ubiquitous polycationic molecules that are present in all prokaryotic and eukaryotic cells, and they serve as important modulators of cell growth, stress, and cell proliferation. Polyamines are present at high concentrations in the periodontal pocket and could potentially affect the stress response of periodontal bacteria to antibiotics. The effects of polyamines on inhibition of growth by amoxicillin (AMX), azithromycin (AZM), and doxycycline (DOX) were investigated with the Y4 strain of Aggregatibacter actinomycetemcomitans (Aa). Bacteria were grown in brain heart infusion broth under the following conditions: (1) Aa only, (2) Aa + polyamine mix (1 mM putrescine, 0.4 mM spermidine, and 0.4 mM spermine), (3) Aa + antibiotic, and (4) Aa + antibiotic + polyamines. Growth curve analysis, minimal inhibitory concentration determination, and transcriptomic studies were conducted. The presence of exogenous polyamines produced a small, but significant increase in Aa growth, and polyamines attenuated the inhibitory effects of AMX, AZM, and DOX on growth. Transcriptomic analysis revealed that polyamines upregulate expression of ribosomal biogenesis proteins and small subunits, attenuate the bacterial stress response to antibiotics, and modulate bacterial nutritional pathways in a manner that could potentially increase the virulence of Aa. In summary, the polyamine‐rich environment found in periodontal pockets appears to protect Aa and reduce its susceptibility to several antimicrobial agents in this in vitro model. [ABSTRACT FROM AUTHOR]

Aim: The present systematic review and meta‐analysis assessed the strength of a reported association between elevated serum anti‐periodontal bacterial antibody responses and coronary heart disease (CHD). Materials and methods: Twenty original studies were identified after systematically searching five databases. The majority (n = 11) compared serum anti‐Porphyromonas gingivalis (Pg) and/or anti‐Aggregatibacter actinomycetemcomitans (Aa) IgG antibody responses between CHD patients and control participants. The strength of the association between serum anti‐Pg antibodies and CHD (n = 10) and serum anti‐Aa antibodies and CHD (n = 6) was investigated using a meta‐analysis approach separately. Results: Most studies (61%) reported that the serum IgG antibody responses were elevated in CHD patients than in controls. The meta‐analyses showed a significant association between elevated serum IgG antibody responses (anti‐Pg and anti‐Aa) and CHD, with pooled odds ratios of 1.23 [95% confidence interval (CI): 1.09–1.38, p =.001] and 1.25 (95% CI: 1.04–1.47, p =.0004), respectively. Conclusions: A modest increase of CHD events in individuals with higher serum anti‐Pg and anti‐Aa IgG antibody responses may support their use as potential biomarkers to detect and monitor at‐risk populations. However, the observed inconsistencies with the design and interpretation of immunoassays warrant standardization of the immunoassays assessing antibody responses against periodontal bacteria. [ABSTRACT FROM AUTHOR]

Background: The facultative bacterium Aggregatibacter actinomycetemcomitans (Aa) is strongly associated with periodontitis and is occasionally found in periodontally healthy subjects. We aimed to determine the prevalence of salivary Aa among patients with either periodontitis Grade B (periodontitis-B) or Grade C (periodontitis-C), periodontally healthy controls (HCs), and to determine if systemic antibodies against Aa or its virulence factor leukotoxin A (LtxA) may serve as biomarkers that reveal the oral presence of the bacterium and discriminate subjects with periodontitis-C, periodontitis-B, or no periodontitis from each other.Methods: Serum and unstimulated saliva samples were collected from patients with periodontitis-C (n = 27), patients with periodontitis-B (n = 34), and HCs (n = 28). Serum level of immunoglobulin G antibodies to fragmented whole Aa and to LtxA were quantified using a bead-based assay. Aa was identified in saliva using quantitative polymerase chain reaction (qPCR). All analyses were adjusted for age, sex, and current smoking status.Results: Aa was present in saliva from 11% of HCs, in 32% of patients with periodontitis-B (P = 0.04 versus HCs), and in 37% of patients with periodontitis-C (P = 0.02 versus HCs). Serum antibodies to fragments of Aa associated significantly with periodontitis-C (P = 0.03), while serum anti-LtxA antibodies associated with both periodontitis-B and periodontitis-C (P = 0.002 and P = 9×10-4 , respectively). Moreover, a significant association between serum anti-LtxA antibodies and Aa count in saliva was observed (P = 0.001). On the basis of serum anti-LtxA antibody levels, patients with periodontitis could be discriminated from HCs (AUC = 0.74 in ROC curve-analysis, P = 0.0003), and carriers of Aa could be discriminated from non-carriers (AUC = 0.78, P <0.0001).Conclusions: Aa is highly prevalent in saliva of patients with periodontitis-B or periodontitis-C. Systemic immunoglobulin G antibodies against LtxA distinguish patients with periodontitis, regardless of grade, from HCs, while their quantity reflects the concurrent bacterial burden in the oral cavity. [ABSTRACT FROM AUTHOR]

Aim: (1) To assess prescription of systemic antibiotics following initial periodontal therapy with and without the availability of microbiological information; (2) To identify factors associated with prescription of systemic antibiotics following initial periodontal therapy. Materials and methods: Twenty‐four clinicians were invited to complete a questionnaire on 20 patient records with respect to periodontal treatment planning, once with microbiological information available and once without. Randomization determined when the microbiological information was provided, and a 3‐month washout period was respected between scoring sessions. Regression analysis was performed to identify factors associated with prescription of systemic antibiotics. Results: Twenty‐one clinicians completed both scoring sessions. Clinicians prescribed systemic antibiotics in on average 56% (95% Confidence Interval (CI) [0.51; 0.61]) of the cases having microbiological information, and in 52% (95% CI [0.47; 0.57]) of the same cases not having that information (p = 0.094). The odds for prescribing systemic antibiotics were 3.34 (95% CI [2.06; 5.42]) times higher when the clinician had at least 3 years of experience, 2.55 (95% CI [1.40; 4.66]) times higher for patients diagnosed with periodontitis stage IV when compared to stage III, 1.08 (95% CI [1.04; 1.11]) times higher for younger patients, 2.78 times (95% CI [1.37; 5.56]) times higher for non‐smokers and 2.22 (95% CI [1.27; 3.85]) times higher when less than three teeth would require extraction. No significant associations with the prescription of systemic antibiotics were found for detection of A.actinomycetemcomitans (p = 0.287), grade of periodontitis (p = 0.499) and gender of the patient (p = 0.067). Conclusions: Based on a limited number of cases and clinicians, several patient and clinician related factors were associated with prescription of systemic antibiotics following initial periodontal therapy. However, microbiological testing was not. [ABSTRACT FROM AUTHOR]

Background: High levels of periodontopathic bacteria as well as Streptococcus anginosus were detected in cancer tissue from patients with esophageal cancer. An association between oral infectious bacteria and esophageal cancer has been reported. Methods: Characteristics of the oral microbiota and periodontal conditions were studied as clinicopathologic factors in patients with esophageal cancer. The study included 61 patients with esophageal cancer and 62 matched individuals without any cancers. Samples of subgingival dental plaque and unstimulated saliva were collected to evaluate the prevalence and abundance of the following oral bacteria using a real‐time polymerase chain reaction assay: Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, and S. anginosus. Results: In the cancer group, the prevalence of all bacteria, with the exception of F. nucleatum, in dental plaque; the prevalence of A. actinomycetemcomitans in saliva; the abundance of all bacteria, with the exception of F. nucleatum and P. intermedia, in dental plaque; and the abundance of A. actinomycetemcomitans and S. anginosus in saliva were significantly higher. Furthermore, a logistic regression analysis suggested that the prevalence of T. forsythia and S. anginosus in dental plaque and of A. actinomycetemcomitans in saliva, as well as a drinking habit, were associated with a high risk of esophageal cancer, with a high odds ratio. Conclusions: The current findings have potential implications for the early diagnosis of esophageal cancer. A positive relation is reported between esophageal cancer and specific oral bacteria. Among these bacteria, Aggregatibacter actinomycetemcomitans, a bacterium that the authors previously linked to esophageal cancer, may have strong diagnostic potential because of its rarity in the microbiota of patients with periodontal disease and periodontally healthy individuals. [ABSTRACT FROM AUTHOR]

Periodontitis is characterized by a dysbiotic microbial community and treatment strategies include the reestablishment of symbiosis by reducing pathogens abundance. Aggregatibacter actinomycetemcomitans (Aa) is frequently associated with rapidly progressing periodontitis. Since the oral ecosystem may be affected by metabolic end‐products of bacteria, we evaluated the effect of soluble compounds released by probiotic lactobacilli, known as postbiotics, on Aa biofilm and expression of virulence‐associated genes. Cell‐free pH‐neutralized supernatants (CFS) of Lactobacillus rhamnosus Lr32, L. rhamnosus HN001, Lactobacillus acidophilus LA5, and L. acidophilus NCFM were tested against a fimbriated clinical isolate of Aa JP2 genotype (1 × 107 CFU/well) on biofilm formation for 24 hr, and early and mature preformed biofilms (2 and 24 hr). Lactobacilli CFS partially reduced Aa viable counts and biofilms biomass, but did not affect the number of viable non‐adherent bacteria, except for LA5 CFS. Furthermore, LA5 CFS and, in a lesser extent HN001 CFS, influenced Aa preformed biofilms. Lactobacilli postbiotics altered expression profile of Aa in a strain‐specific fashion. Transcription of cytolethal distending toxin (cdtB) and leukotoxin (ltxA) was downregulated by CFS of LA5 and LR32 CFS. Although all probiotics produced detectable peroxide, transcription of katA was downregulated by lactobacilli CFS. Transcription of dspB was abrogated by LR32 and NCFM CFS, but increased by HN001, whereas expression of pgA was not affected by any postbiotic. Our data indicated the potential of postbiotics from lactobacilli, especially LA5, to reduce colonization levels of Aa and to modulate the expression of virulence factors implicated in evasion of host defenses. [ABSTRACT FROM AUTHOR]

The role of periodontopathogens in inflammatory endothelial dysfunction is not known. This study characterizes a three‐dimensional model with human coronary artery endothelial cells on three‐dimensional (HCAEC‐3D) type I collagen scaffolds to evaluate whether infection with Aggregatibacter actinomycetemcomitans induces a proinflammatory response associated with atherosclerosis. The HCAEC‐3D culture was physicochemically characterized with regard to biocompatibility and barrier function. Then, the culture was infected with A. actinomycetemcomitans strain ATCC 29522 at multiplicities of infection (MOIs) of 1:1, 1:10, and 1:100. Cultures without infection and stimulated with A. actinomycetemcomitans lipopolysaccharide were used as controls. The secretion of soluble factors (IL‐6, IL‐1β, MCP‐1, RANTES, MIP‐1, IL‐8, IL‐1α, and TNF‐α) was evaluated via flow cytometry; TGF‐β1 was evaluated via enzyme‐linked immunosorbent assay (ELISA). The adhesion and migration of fluorescent human THP‐1 monocytes was evaluated. IL‐8, MCP‐1, and IL‐6 secretion increased in a dose‐dependent manner with A. actinomycetemcomitans infection and was significantly greater than that under control treatment. The concentration of TGF‐β1 was significantly higher at MOI 1:100 than in controls. Treatment of the 3D cultures with A. actinomycetemcomitans at different MOIs induced significant differences in the adhesion of monocytes to the endothelium compared to the control without infection. Lastly, conditioned media from 3D cultures treated with A. actinomycetemcomitans induced monocyte migration. The effects of IL‐8, MCP‐1, IL‐6, and TGF‐β1 on the endothelium indicate the ability of A. actinomycetemcomitans to induce an inflammatory response through a mechanism of monocyte adhesion and migration and endothelial dysfunction. [ABSTRACT FROM AUTHOR]

Background and Objective: Several studies have demonstrated that mast cells are equipped with versatile tools to combat and kill bacteria. Additionally, mast cells produce and secrete a variety of mediators, which either regulate the host's immune system or directly attack bacteria. In this study, the intracellular microbicidal capacity of mast cells against Aggregatibacter actinomycetemcomitans was evaluated. Methods: Murine mast cells were challenged in vitro with A actinomycetemcomitans for 3, 5, 10, and 24 hours. Subsequently, the colony‐forming units were counted. Additionally, the production and release of nitric oxide and hydrogen peroxide were analyzed by DAF‐FM diacetate, the Griess reaction, and the Amplex Red kit, respectively. Cell death was evaluated using FITC Annexin V and propidium iodide staining. Results: Mast cells are able to efficiently eliminate periodontopathogen, with best results after 10 hours of intracellular challenge. The production/release of nitric oxide—and to a lesser extent of hydrogen peroxide—by mast cells was in agreement with its microbicidal capacity. Ninety percent of the mast cells maintained their cellular viability even after 24 hours of bacterial challenge. Conclusions: This is—to the best of our knowledge—the first report to describe the intracellular microbicidal activity of mast cells against A actinomycetemcomitans, concerning the production and release of potentially bactericidal substances. Further, the low number of cell deaths confirms that the decreased number of colony‐forming units was due to the higher antimicrobial activity of mast cells. The results highlight the importance of these cells in the defense mechanisms of biofilm‐induced periodontal disease. [ABSTRACT FROM AUTHOR]

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium associated with localized aggressive periodontitis, as well as other systemic diseases. This organism produces a number of virulence factors, all of which provide some advantage to the bacterium. Several studies have demonstrated that clinical isolates from diseased patients, particularly those of African descent, frequently belong to specific clones of A. actinomycetemcomitans that produce significantly higher amounts of a protein exotoxin belonging to the repeats-in-toxin (RTX) family, leukotoxin (LtxA), whereas isolates from healthy patients harbor minimally leukotoxic strains. This finding suggests that LtxA might play a key role in A. actinomycetemcomitans pathogenicity. Because of this correlation, much work over the past 30 years has been focused on understanding the mechanisms by which LtxA interacts with and kills host cells. In this article, we review those findings, highlight the remaining open questions, and demonstrate how knowledge of these mechanisms, particularly the toxin's interactions with lymphocyte function-associated antigen-1 (LFA-1) and cholesterol, enables the design of targeted anti-LtxA strategies to prevent/treat disease. [ABSTRACT FROM AUTHOR]

Extracellular electron transfer (EET) via cell‐bound redox enzymes and/or redox shuttles is extensively studied in environmental bacteria. Meanwhile, EET capable pathogens have been identified in the human gut. However, other EET‐capable bacterial niches where possible biofilm infections are prominent have scarcely been explored. Herein, we electrochemically characterized human oral biofilm pathogens, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, to examine their EET capability. Both strains showed current production with the electrode poised at +0.4 V vs. a standard hydrogen electrode, which was associated with a decrease in electron‐donor concentration, coupled with the appearance of oxidative peaks in differential pulse (DP) and cyclic voltammograms (CV). Addition of antibiotics that suppress the biosynthesis of membrane or protein showed a significant current decrease, demonstrating that current production reflects the cellular activity in these pathogens. DPV‐ and CV‐based kinetic analyses supported by transmission electron microscopy of the cells stained for transition metals suggest a potential EET mechanism associated with the presence of redox enzymes on the cell membrane. These results could be the basis to reevaluate human oral pathogens from an electroactive point of view. The identified electrochemical activity of the two strains can be an effective test for assessing the impact of antibacterial compounds on the pathogen cellular activity on an electrode. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present study was to establish a rodent peri‐implantitis model induced by a mixed bacterial infection characterized by bone loss and semi‐quantitative graduation of peri‐implant inflammation in histological sections. Materials and Methods: Two titanium implants were implanted in Sprague‐Dawley rats, bilaterally in each maxilla. After 3 weeks healing, the rats were randomized into three groups according to different treatments over the next 3 months: Antibiotic‐Group with oral lavage of antibiotics; Bacteria‐Group with oral lavage of Streptococcus oralis and Aggregatibacter actinomycetemcomitans; and Untreated Group with standard housing and no additional treatment. Maxillae were dissected to perform microscopic and histological analysis of bone height and peri‐implant tissues. Results: The bone level, measured at one implant site per animal, in the Bacteria‐Group (2.60 ± 0.39 mm) was significantly reduced compared to the Antibiotic‐Group (2.29 ± 0.32 mm) after 3 months. The differences of bone height in the Bacteria‐Group and the Untreated Group (2.46 ± 0.27 mm) did not reach statistical significance. The inflammatory response with respect to the number of inflammatory cells and fibrous tissue compartments of the peri‐implant tissues in the Bacteria‐Group was significantly increased compared with the Antibiotic‐Group (p <.05). S. oralis and A. actinomycetemcomitans DNAs were detected in the Bacteria‐Group. Conclusions: This rat model of peri‐implantitis used oral bacterial lavage for the induction of an inflammatory host response and bone loss. Additional bacterial treatment enhances the peri‐implant phenotype, so that significant differences to a reduced bacterial load similar to the human peri‐implantitis disease can be identified. [ABSTRACT FROM AUTHOR]

The etiopathogenesis of severe periodontitis includes herpesvirus-bacteria coinfection. This article evaluates the pathogenicity of herpesviruses (cytomegalovirus and Epstein-Barr virus) and periodontopathic bacteria (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis) and coinfection of these infectious agents in the initiation and progression of periodontitis. Cytomegalovirus and A. actinomycetemcomitans/P. gingivalis exercise synergistic pathogenicity in the development of localized ("aggressive") juvenile periodontitis. Cytomegalovirus and Epstein-Barr virus are associated with P. gingivalis in adult types of periodontitis. Periodontal herpesviruses that enter the general circulation may also contribute to disease development in various organ systems. A 2-way interaction is likely to occur between periodontal herpesviruses and periodontopathic bacteria, with herpesviruses promoting bacterial upgrowth, and bacterial factors reactivating latent herpesviruses. Bacterial-induced gingivitis may facilitate herpesvirus colonization of the periodontium, and herpesvirus infections may impede the antibacterial host defense and alter periodontal cells to predispose for bacterial adherence and invasion. Herpesvirus-bacteria synergistic interactions, are likely to comprise an important pathogenic determinant of aggressive periodontitis. However, mechanistic investigations into the molecular and cellular interaction between periodontal herpesviruses and bacteria are still scarce. Herpesvirus-bacteria coinfection studies may yield significant new discoveries of pathogenic determinants, and drug and vaccine targets to minimize or prevent periodontitis and periodontitis-related systemic diseases. [ABSTRACT FROM AUTHOR]

The oral pathogen, Aggregatibacter actinomycetemcomitans, produces a number of virulence factors, including a leukotoxin (LtxA), which specifically kills human white blood cells, to provide a colonization advantage to the bacterium. Strains of A. actinomycetemcomitans that produce more LtxA have been more closely linked to disease, indicating that this toxin plays a key role in pathogenesis of the bacterium. Disruption of the activity of LtxA thus represents a promising approach to reducing the pathogenicity of the bacterium. Catechins are polyphenolic molecules derived from plants, which have shown potent antibacterial and antitoxin activities. We have previously shown that galloylated catechins are able to prevent LtxA delivery to host cells by altering the toxin's secondary structure and preventing binding to cholesterol on the host cell membrane. Here, we have investigated how one particular galloylated catechin, epigallocatechin gallate (EGCg), affects A. actinomycetemcomitans growth and toxin secretion. Our results demonstrate that EGCg, at micromolar concentrations, inhibits A. actinomycetemcomitans growth, as has been reported for other bacterial species. At subinhibitory concentrations, EGCg promotes LtxA production, but the toxicity of the bacterial supernatant against human immune cells is reduced. The results of our biophysical studies indicate that this seemingly contradictory result is caused by an EGCg-mediated enhancement of LtxA affinity for the bacterial cell surface. Together, these results demonstrate the potential of EGCg in the treatment of virulent A. actinomycetemcomitans infections. [ABSTRACT FROM AUTHOR]

Among the main bacteria implicated in the pathology of periodontal disease, Aggregatibacter actinomycetemcomitans (Aa) is well known for causing loss of periodontal attachment and systemic disease. Recent studies have suggested that secreted extracellular RNAs (exRNAs) from several bacteria may be important in periodontitis, although their role is unclear. Emerging evidence indicates that exRNAs circulate in nanosized bilayered and membranous extracellular vesicles (EVs) known as outer membrane vesicles (OMVs) in gram-negative bacteria. In this study, we analyzed the small RNA expression profiles in activated human macrophage-like cells (U937) infected with OMVs from Aa and investigated whether these cells can harbor exRNAs of bacterial origin that have been loaded into the host RNA-induced silencing complex, thus regulating host target transcripts. Our results provide evidence for the cytoplasmic delivery and activity of microbial EV-derived small exRNAs in host gene regulation. The production of TNF-α was promoted by exRNAs via the TLR-8 and NF-κB signaling pathways. Numerous studies have linked periodontal disease to neuroinflammatory diseases but without elucidating specific mechanisms for the connection. We show here that intracardiac injection of Aa OMVs in mice showed successful delivery to the brain after crossing the blood-brain barrier, the exRNA cargos increasing expression of TNF-α in the mouse brain. The current study indicates that host gene regulation by microRNAs originating from OMVs of the periodontal pathogen Aa is a novel mechanism for host gene regulation and that the transfer of OMV exRNAs to the brain may cause neuroinflammatory diseases like Alzheimer's. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of the periodontal treatment on Aggregatibacter actinomycetemcomitans JP2 clone, and the IgG serum levels against its outer membrane protein (Omp29) and A. actinomycetemcomitans serotypes in aggressive periodontitis (AgP). Subjects and Methods: Seventeen patients with generalized (GAgP), 10 with localized (LAgP), and 10 healthy controls were included. AgP participants were submitted to periodontal treatment—scaling and root planing plus antibiotics (SRP+A). Periodontal parameters, for example, probing depth (PD) and clinical attachment loss (CAL), were evaluated at baseline and at 1‐year. Serum IgG against Omp29 and serotypes a, b, and c were determined by ELISA. The levels of A. actinomycetemcomitans JP2 clone were determined in subgingival biofilm samples by qPCR. Results: Periodontal treatment resulted in significant reductions of PD, CAL, and IgG levels against Omp29, serotypes b, and c. After therapy, IgG levels against A. actinomycetemcomitans serotypes, as well as the levels of the JP2 clone in AgP, became similar to controls. The reduction in JP2 clone count was correlated with a reduction of PD and IgG response against Omp29. Conclusion: Scaling and root planing plus antibiotics decreased IgG levels response against Omp29 and A. actinomycetemcomitans serotypes involved in the disease (b and c), while the serum response increased against tne commensal serotype (a), similar to what occurs in periodontally healthy individuals. [ABSTRACT FROM AUTHOR]

Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA‐treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA‐treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA‐induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis. [ABSTRACT FROM AUTHOR]

It has previously been shown that the presence of Aggregatibacter actinomycetemcomitans in subgingival plaque is significantly associated with increased risk for clinical attachment loss. The highly leukotoxic JP2 genotype of this bacterium is frequently detected in adolescents with aggressive forms of periodontitis. The aims of the study were to quantify the levels of JP2 and non‐JP2 genotypes of A. actinomycetemcomitans in saliva of Moroccan adolescents with the JP2 genotype earlier detected in the subgingival plaque. The salivary concentrations of inflammatory proteins were quantified and linked to the clinical parameters and microbial findings. Finally, a mouth rinse with leukotoxin‐neutralizing effect was administrated and its effect on the levels the biomarkers and A. actinomycetemcomitans examined. The study population consisted of 22 adolescents that previously were found to be positive for the JP2 genotype in subgingival plaque. Periodontal registration and sampling of stimulated saliva was performed at baseline. A mouth rinse (active/placebo) was administrated, and saliva sampling repeated after 2 and 4 weeks rinse. The salivary levels of JP2 and non‐JP2 were analyzed by quantitative PCR and inflammatory proteins by ELISA. Both the JP2 and the non‐JP2 genotype were detected in all individuals with significantly higher levels of the non‐JP2. Enhanced levels of the JP2 genotype of A. actinomycetemcomitans was significantly correlated to the presence of attachment loss (≥3 mm). Salivary concentrations of inflammatory biomarkers did not correlate to periodontal condition or levels of A. actinomycetemcomitans. The use of active or placebo leukotoxin‐neutralizing mouth rinse did not significantly interfered with the levels of these biomarkers. Saliva is an excellent source for detection of A. actinomycetemcomitans on individual basis, and high levels of the JP2 genotype were significantly associated with the presence of clinical attachment loss. [ABSTRACT FROM AUTHOR]

Background: Aggregatibacter actinomycetemcomitans expresses several virulence factors that may contribute to the pathogenesis of periodontitis. Based on the antigenicity of the O-polysaccharide component of the lipopolysaccharide (LPS), different A. actinomycetemcomitans serotypes have been described. Among them, serotype b has demonstrated a stronger capacity to trigger Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor production on immune cells in vitro. With a murine model of experimental periodontitis, this investigation aimed to analyze the alveolar bone resorption and the pattern of immune response triggered by the different A. actinomycetemcomitans serotypes within periodontal lesions.Methods: For periodontal lesion induction, mice were orally infected with the different A. actinomycetemcomitans serotypes or their purified LPS. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. Bacterial infection, receptor activator of nuclear factor-kappa B ligand (RANKL) and Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor levels were quantified by quantitative polymerase chain reaction (qPCR). T lymphocytes isolated from periodontal lesions were analyzed by flow cytometry.Results: In periodontal lesions, serotype b of A. actinomycetemcomitans induced higher alveolar bone resorption and expression of RANKL compared with the other serotypes. In addition, serotype b induced greater levels of Th1- and Th17-related cytokines, CC-chemokines, and CC-chemokine receptors than the others. Similarly, higher numbers of infiltrating Th1 and Th17 lymphocytes were detected in serotype b-induced periodontal lesions.Conclusions: These results demonstrate that periodontal lesions induced with different A. actinomycetemcomitans serotypes elicited distinct alveolar bone resorption and immune response. In particular, serotype b was more pathogenic than the others and induced stronger Th1 and Th17 patterns of immune responses during experimental periodontitis. [ABSTRACT FROM AUTHOR]

Background: Previous studies have provided substantial evidence of the association of Aggregatibacter actinomycetemcomitans, and its highly leukotoxic JP2 genotype, with localized aggressive periodontitis (LAgP). The present study aims to evaluate presence of JP2 in individuals with LAgP after periodontal treatment.Methods: Sixty African-American patients with LAgP, aged 5 to 25 years, were examined. At baseline, probing depth (PD), clinical attachment level (CAL), bleeding on probing, and plaque index were measured, and subgingival plaque was collected from LAgP diseased and healthy sites for each participant. Patients received whole-mouth ultrasonic debridement, scaling and root planing, and a 7-day prescription of amoxicillin and metronidazole. Participants were reevaluated and resampled and received regular maintenance therapy at 3, 6, and 12 months after treatment. Polymerase chain reaction was used to detect presence of the JP2 genotype before and after treatment.Results: At baseline, the JP2 sequence was identified in 75% of LAgP diseased sites and in 56.67% of healthy sites. At 3, 6, and 12 months after treatment, the number of patients was 40, 31, and 31, respectively, and JP2 detection decreased to 17.5%, 6.45%, and 3.23%, respectively, in diseased sites (P <0.001) and to 2.5%, 3.23%, and 0%, respectively, in healthy sites (P <0.001). Clinical parameters of disease were also significantly reduced after therapy (P <0.001). Additionally, significant correlations were observed between JP2 presence and mean PD (P <0.002) and CAL (P <0.001), after therapy.Conclusion: Periodontal therapy was successful in reducing clinical parameters of LAgP and subgingival presence of JP2 in diseased and healthy sites. [ABSTRACT FROM AUTHOR]

Background and Objective Aggregatibacter actinomycetemcomitans is involved in oral and systemic infections, and is associated with, eg aggressive forms of periodontitis and with endocarditis. The cagE gene encodes a ≈39 kDa putative exotoxin expressed by A. actinomycetemcomitans. The level of conservation of cagE, and its possible significance in periodontal disease, has not yet been thoroughly investigated. In the present study, the role of the cagE gene as a diagnostic marker has been investigated. Material and Methods We have used conventional polymerase chain reaction ( PCR), quantitative PCR and whole genome sequencing data to determine the prevalence of cagE in A. actinomycetemcomitans based on analysis of: (i) 249 isolates, collected and cultivated in a Ghanaian longitudinal cohort study; (ii) a serotype b collection of 19 strains; and (iii) the 36 A. actinomycetemcomitans genomes available in the NCBI database. Results Whereas cagE was absent in the other serotypes, our data support that this gene sequence is linked to a virulent and highly leukotoxic group of serotype b strains, including both JP2 and non- JP2 genotypes of A. actinomycetemcomitans. Conclusion We propose that cagE has the potential to be used as a PCR-based gene marker for the identification of a virulent and highly leukotoxic group of serotype b strains, including both JP2 and non- JP2 genotypes. This finding might be of importance in the risk assessment of the development of periodontal attachment loss in young individuals and hence suggested to be a relevant discovery in future development of new diagnostic tools and/or treatment strategies. [ABSTRACT FROM AUTHOR]

Aim To evaluate the effects of photodynamic therapy ( PDT) in the nonsurgical treatment of chronic periodontitis. Materials and methods A randomized, single-blind, controlled, parallel-group clinical trial was performed. Sixty patients were enrolled: 20 healthy controls and 40 patients with periodontitis. The 40 patients were randomized for scaling and root planing ( SRP) or SRP + PDT. Periodontal (plaque index, probing depth, clinical recession, clinical attachment level, bleeding on probing and gingival crevicular fluid volume, corresponding to 381 versus 428 critical sites), microbiological ( Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Campylobacter rectus presence, 18 versus 19 samples) and biochemical (interleukin ( IL)-1β, IL-6 and tumour necrosis factor ( TNF)-α, receptor activator of nuclear factor-kappaB ligand ( RANK-L) and osteoprotegerin ( OPG) levels, 18 versus 19 samples) parameters were recorded. Results Within each group, significant improvements were found for clinical parameters, though without significant differences between groups. RANK-L was significantly decreased at week 13 in the SRP + PDT group compared with the SRP group. SRP + PDT, but not SRP alone, significantly reduced the abundance of A. actinomycetemcomitans. Conclusions Except for a significant decrease in the pathogenic burden of A. actinomycetemcomitans, coadjuvant PDT resulted in no additional improvement compared with SRP alone in patients diagnosed with moderate-to-advanced chronic periodontitis. [ABSTRACT FROM AUTHOR]

Aim Leukotrienes ( LTs) are pro-inflammatory lipid mediators formed by the enzyme 5-lipoxygenase (5- LO). The involvement of 5- LO metabolites in periodontal disease ( PD) is not well defined. This study aimed to assess the role of 5- LO in experimental PD induced by Aggregatibacter actinomycetemcomitans ( Aa). Material and Methods In vivo experiments were carried out using SV129 wild-type ( WT) and 5- LO-deficient ( 5lo-/-) mice inoculated with Aa. Osteoclasts were stimulated in vitro with Aa LPS in the presence or not of selective inhibitors of the 5- LO pathway, or LTB4 or platelet-activating factor ( PAF), as PAF has already been shown to increase osteoclast activity. Results In 5lo -/- mice, there were no loss of alveolar bone and less TRAP-positive osteoclasts in periodontal tissues, after Aa inoculation, despite local production of TNF-α and IL-6. The differentiation and activity of osteoclasts stimulated with Aa LPS were diminished in the presence of BLT1 antagonist or 5- LO inhibitor, but not in the presence of cysteinyl leukotriene receptor antagonist. The osteoclast differentiation induced by PAF was impaired by the BLT1 antagonism. Conclusion In conclusion, LTB4 but not Cys LTs is important for Aa-induced alveolar bone loss. Overall, LTB4 affects osteoclast differentiation and activity and is a key intermediate of PAF-induced osteoclastogenesis. [ABSTRACT FROM AUTHOR]

Background: Presence of epithelial desquamation, erythema, and erosions on gingival tissue is usually described in the literature as desquamative gingivitis (DG). A wide range of autoimmune/dermatologic disorders can manifest as DG, although the two more common are oral lichen planus and mucous membrane pemphigoid. The aim of this study is to investigate prevalence of 11 periodontopathogenic microorganisms in patients with DG and to compare it with the microbiologic status of individuals affected by plaque-induced gingivitis (pGI).Methods: Cross-sectional clinical and microbiologic data were obtained from 66 patients (33 in each group). Subgingival plaque samples were analyzed using semiquantitative polymerase chain reaction analysis.Results: Statistically significant difference, but with little clinical significance, was observed in gingival conditions between the two groups, probably due to the worse home control hygiene of patients with DG. Prevalence and levels of Aggregatibacter actinomycetemcomitans, Eikenella corrodens, and Fusobacterium nucleatum/periodonticum were statistically higher in samples from patients with DG than in those with pGI. In multivariate regression models, subgingival colonization of A. actinomycetemcomitans and F. nucleatum/periodonticum was not statistically associated with DG, whereas, high levels of E. corrodens were associated with 13-fold increased odds for DG.Conclusions: Microbiologic differences were found in subgingival plaque for patients with DG and pGI. This may suggest possible association between periodontal pathogens and DG. [ABSTRACT FROM AUTHOR]

Background and Objective The periodontal pathogen Aggregatibacter actinomycetemcomitans has been proposed as pro-atherogenic, and complement-mediated adherence to red blood cells ( RBCs) may facilitate its systemic spread. We investigated the ability of four strains of A. actinomycetemcomitans with differential expression of leukotoxin A (LtxA) and fimbriae to activate complement, adhere to RBCs and elicit cytokine responses by mononuclear cells ( MNCs). Material and Methods Aggregatibacter actinomycetemcomitans serotype b strains HK 921, HK 1651, HK 2092 and HK 2108 were fluorescence-labeled, incubated with human whole blood cells in the presence of autologous serum, and assessed for RBC adherence by flow cytometry and for capacity to induce cytokine production by cytometric bead array analysis. The levels of IgG to A. actinomycetemcomitans serotype b were quantified by ELISA, as was consumption of complement. Results The JP2 clone variants HK 1651 and, to a lesser extent, HK 2092, consumed complement efficiently, while HK 2108 (= strain Y4) consumed complement poorly. Nonetheless, the four tested strains adhered equally well to RBCs in the presence of autologous serum, without causing RBC lysis. The JP2 clone variant HK 2092, selectively lacking LtxA production, induced higher production of tumor necrosis factor ( TNF)-α, interleukin ( IL)-1β, IL-6 and IL-10 by MNCs than did the other three strains, while the four strains induced similar production of IL-12p70. RBCs facilitated the HK 2092-induced production of TNF-α and IL-1β, and IL-6 was enhanced by RBCs, and this facilitation could be counteracted by blockade of complement receptor 3 ( CD11b/ CD18). Conclusion Our data suggest that the JP2 clone of A. actinomycetemcomitans, most closely resembled by the variant HK 1651, activates complement well, while strain Y4, represented by HK 2108, activates complement poorly. However, all strains of A. actinomycetemcomitans adhere to RBCs and, when capable of producing LtxA, prevent production of inflammatory cytokines by MNCs. This 'immunologically silent' immune adherence may facilitate systemic spread and atherogenesis. [ABSTRACT FROM AUTHOR]

Aim The aim of the present study was to evaluate the influence of the baseline detection of Aggregatibacter actinomycetemcomitans ( A. actinomycetemcomitans) on the clinical outcomes of moxifloxacin ( MOX) as an adjunct to full-mouth scaling and root planing ( SRP) in generalized aggressive periodontitis ( GAg P). Methods Forty patients were randomly distributed to two therapy protocols: SRP + placebo or SRP combined with MOX. A. actinomycetemcomitans was detected using culture methods. The significance of the treatment option ( MOX or SRP + placebo) on the dependent variables (probing depth [ PD] and clinical attachment level [ CAL]), considering the interaction with the baseline detection of A. actinomycetemcomitans, was estimated. Results MOX therapy led to a higher significant PD reduction and CAL gain in A. actinomycetemcomitans-positive patients at baseline. In A. actinomycetemcomitans-positive patients, the reduction of sites ≥5 mm was higher in the MOX group. A. actinomycetemcomitans was not present in sites with PD ≥6 mm in the MOX group. The interactions of A. actinomycetemcomitans and MOX were significantly associated with CAL gain and PD reduction at 6 months. Conclusions Adjunctive MOX trended toward better clinical responses in A. actinomycetemcomitans-positive patients at baseline. These results suggest that A. actinomycetemcomitans at baseline might modify the effect of adjunctive MOX in GAg P. [ABSTRACT FROM AUTHOR]

Background: The collection of subgingival plaque samples with paper points is time-consuming and accident-sensitive. However, the collection of saliva is simple and contains pathogens of all intraoral surfaces. The aim of this study is to investigate whether a sampling strategy with mouthrinse (mouthrinse sample [MSP]; test) leads to results comparable with standard sampling method (multiple site test from the deepest pocket of each quadrant [MT4]; control).Methods: In 50 patients with periodontitis, subgingival plaque was sampled from the deepest pocket of each quadrant by using paper points and by gaining saliva with saline mouthrinse. Analysis was performed using a commercially available polymerase chain reaction test for 11 periodontal pathogens.Results: Detection frequency of Aggregatibacter actinomycetemcomitans (MT4/MSP: 42%/36%), Porphyromonas gingivalis (78%/66%), Tannerella forsythia (98%/84%), Treponema denticola (94%/74%), Parvimonas micra (86%/62%), Campylobacter rectus (90%/76%), Eubacterium nodatum (64%/30%), Prevotella intermedia (58%/54%), and Eikenella corrodens (90%/82%) was higher with MT4 than MSP. For Fusobacterium nucleatum (100%/100%), there was no difference between test and control. Only detection frequency of Capnocytophaga species (68%/74%) was higher with MSP than MT4. Differences were significant for P. gingivalis, T. forsythia, T. denticola, P. micra, C. rectus, and E. nodatum.Conclusions: There is no significant difference between MT4 and MSP for detection frequency of key pathogen A. actinomycetemcomitans. Key pathogens P. gingivalis, T. forsythia, T. denticola, P. micra, C. rectus, and E. nodatum show statistically higher detection frequencies with MT4. [ABSTRACT FROM AUTHOR]

Periodontal disease exemplifies a chronic and recurrent infection with a necessary biofilm component. Mucosal inflammation is a hallmark response of the host seen in chronic diseases, such as colitis, gingivitis, and periodontitis (and the related disorder peri-implantitis). We have taken advantage of our recently developed rat model of human peri-implantitis that recapitulates osteolysis, the requirement of biofilm formation, and the perpetuation of the bona fide disease state, to test a new therapeutic modality with two novel components. First we used hyperimmune antiserum directed against the DNABII family of proteins, now known to be a critical component of the extracellular matrix of bacterial biofilms. Second we delivered the antiserum as cargo in biodegradable microspheres to the site of the biofilm infection. We demonstrated that delivery of a single dose of anti-DNABII in poly(lactic-co-glycolic acid) (PLGA) microspheres induced significant resolution of experimental peri-implantitis, including marked reduction of inflammation. These data support the continued development of a DNABII protein-targeted therapeutic for peri-implantitis and other chronic inflammatory pathologies of the oral cavity in animals and humans. [ABSTRACT FROM AUTHOR]

Objectives: Periodontal disease occurs frequently in patients with limited cutaneous systemic sclerosis (lcSSc) while data about underlying pathways contributing to periodontal changes are scarce. The aim of this study was to evaluate periodontal disease and to investigate its association with endothelial dysfunction and clinical changes in patients with lcSSc., Methods: In 38 lcSSc patients and 38 controls, periodontal status was evaluated by disease-specific questionnaire, dental examination including bleeding on probing (BOP), pocket depth, and plaque index, and dental panoramic radiograph. Periodontopathogen bacteria were collected subgingivally using paper points and interleukin-1 (IL-1) gene polymorphisms were evaluated using buccal swabs. Endothelial dysfunction was measured by flow-mediated dilatation, pulse-wave velocity and biochemical analysis, including arginine metabolites and endothelial microparticles. Additionally, lcSSc-specific clinical changes and parameters were recorded., Results: Periodontitis was present in 31 patients with lcSSc (81.6%) and in 27 controls (71.1%) (p = .280). LcSSc patients had a lower teeth number (p = .039) and Eikenella corrodens was to a higher degree detectable in patients with lcSSc (p = .041) while the remaining periodontal parameters revealed no differences between both cohorts. Significant correlations between parameters of arterial stiffness, EUSTAR index, number of teeth and BOP were observed (all p < .05). Detection of Prevotella intermedia was associated with selected IL-1 gene polymorphisms (p = .032) and Porphyromonas gingivalis was associated with severe periodontitis (p = .041)., Conclusion: Periodontal disease may occur frequently in patients with lcSSc and may be associated with arterial stiffness and with SSc activity., (© 2023 The Authors. Journal of Periodontal Research published by John Wiley & Sons Ltd.)

Background: A randomized split-mouth controlled clinical trial was conducted to evaluate the efficacy of photodynamic therapy (PDT) in reducing Aggregatibacter actinomycetemcomitans (Aa) in periodontitis patients.Methods: Twenty patients with periodontitis were recruited for the trial. Following random allocation of either quadrants of the selected jaw to test or control treatment, conventional non-surgical periodontal therapy (NSPT) was performed. In addition, the test side received adjunct photodynamic therapy. Probing depth (PD), clinical attachment level, bleeding on probing (BoP) and plaque scores (PS%) were recorded at phase 0 (baseline), phase 1 (immediately after NSPT), phase 2 (7 days following NSPT), phase 3 (1 month following NSPT) and phase 4 (3 months following NSPT). Subgingival plaque samples for quantification of Aa by real-time polymerase chain reaction was performed at phases 0, 1, 2 and 4.Results: There was a significant clinical improvement at phases 3 and 4 compared with baseline while BoP reduced significantly only in the test group at phase 4. However, no difference in the quantification of Aa was detected between the groups.Conclusions: Within the limits of the study, PDT adjunct to scaling and root planing does not lead to quantitative reduction of Aa in periodontitis patients. [ABSTRACT FROM AUTHOR]

Aim: To evaluate subgingival instrumentation (SI) in periodontitis stage III and IV, grade B and C with systemic antibiotics (AB) only after detection of Aggregatibacter actinomycetemcomitans., Materials and Methods: Patients of the Department of Periodontology of Goethe University Frankfurt/Germany were screened for microbiological testing between 2008 and 2018. All patients with aggressive and generalized severe chronic periodontitis were tested. In case of positive subgingival A. actinomycetemcomitans tests, SI was combined with AB; in all other cases it was not (nAB). Clinical examinations were performed before (T0), 12.4 (9.4/15.1) weeks after SI (T1), and at the last supportive periodontal care (T2; 3.1 [1.4/5.5] years after T1). Results at T1/T2 were assessed as "treat-to-target" endpoint (≤4 sites with probing pocket depths ≥5 mm)., Results: Four-hundred and twenty-five patients (280 stage III/145 stage IV, 95 grade B/330 grade C) provided complete data (AB 144/nAB 281) for T0 and T1, and 332 (AB 121/nAB 211) for T2. At T1/T2, AB resulted in 53 (37%)/76 (63%) patients with "treat-to-target" endpoint, and nAB in 76 (27%)/91 (43%) (p = .038/.001)., Conclusions: In periodontitis stage III and IV, grade B and C with subgingival A. actinomycetemcomitans infection, SI with AB resulted in higher rate of "treat-to-target" endpoint than exclusive SI in patients without the infection., (© 2023 The Authors. Journal of Clinical Periodontology published by John Wiley & Sons Ltd.)

Objective: The objective of this systematic review and meta-analysis was to evaluate the effect of periodontal surgery on the subgingival microbiome., Background: Periodontitis is a chronic inflammation of the tooth supporting tissues caused by the dysbiosis of the subgingival biofilm. It is managed through different non-surgical and surgical treatment modalities. Recent EFP S3 guidelines recommended performing periodontal surgery as part of Step 3 periodontitis treatment after Step 1 and Step 2 periodontal therapy, with the aim to achieve pocket closure of persisting sites. Changes in the sub-gingival microbiome may explain the treatment outcomes observed at different time points. Various microbiological detection techniques for disease-associated pathogens have been evolved over time and have been described in the literature. However, the impact of different types of periodontal surgery on the subgingival microbiome remains unclear., Methods: A systematic literature search was conducted in Medline, Embase, LILACS and Cochrane Library supplemented by manual search (23DEC2019, updated 21APR2022)., Results: From an initial search of 3046 studies, 28 were included according to our specific inclusion criteria. Seven microbiological detection techniques were used to analyse disease-associated species in subgingival plaque samples: optical microscope, culture, polymerase chain reaction (PCR), checkerboard, enzymatic reactions, immunofluorescence and 16S gene sequencing. The included studies exhibited differences in various aspects of their methodologies such as subgingival plaque sample collection or treatment modalities. Clinical data showed a significant decrease in probing pocket depths (PPD) and clinical attachment loss (CAL) after periodontal surgery. Microbiological findings were overall heterogeneous. Meta-analysis was performed on a sub-cohort of studies all using checkerboard as a microbiological detection technique. Random effect models for Treponema denticola (T. denticola), Porphyromonas gingivalis (P. gingivalis) and Tannerella forsythia (T. forsythia) did not show a significant effect on mean counts 3 months after periodontal surgery. Notably, Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) showed a significant increase 3 months after periodontal surgery. 16S gene sequencing was used in one included study and reported a decrease in disease-associated species with an increase in health-associated species after periodontal surgery at 3 and 6 months., Conclusion: This systematic review has shown that the effect of periodontal surgery on the changes in subgingival microbiome is heterogeneous and may not always be associated with a decrease in disease-associated species. The variability could be attributed to the microbiological techniques employed for the analysis. Therefore, there is a need for well-designed and adequately powered studies to understand how periodontal surgery influences the subgingival microbiome and how the individual's microbiome affects treatment outcomes after periodontal surgery., (© 2023 The Authors. Journal of Periodontal Research published by John Wiley & Sons Ltd.)

The Th17/IL-17 pathway is implicated in the pathogenesis of periodontitis (PD), however the mechanisms are not fully understood. We investigated the mechanism by which the periodontal pathogens Porphyromonas gingivalis ( Pg) and Aggregatibacter actinomycetemcomitans ( Aa) promote a Th17/IL-17 response in vitro, and studied IL-17+ CD4+ T-cell frequencies in gingival tissue and peripheral blood from patients with PD versus periodontally healthy controls. Addition of Pg or Aa to monocyte/CD4+ T-cell co-cultures promoted a Th17/IL-17 response in vitro in a dose- and time-dependent manner. Pg or Aa stimulation of monocytes resulted in increased CD40, CD54 and HLA-DR expression, and enhanced TNF-α, IL-1β, IL-6 and IL-23 production. Mechanistically, IL-17 production in Pg-stimulated co-cultures was partially dependent on IL-1β, IL-23 and TLR2/TLR4 signalling. Increased frequencies of IL-17+ cells were observed in gingival tissue from patients with PD compared to healthy subjects. No differences were observed in IL-17+ CD4+ T-cell frequencies in peripheral blood. In vitro, Pg induced significantly higher IL-17 production in anti-CD3 mAb-stimulated monocyte/CD4+ T-cell co-cultures from patients with PD compared to healthy controls. Our data suggest that periodontal pathogens can activate monocytes, resulting in increased IL-17 production by human CD4+ T cells, a process that appears enhanced in patients with PD. [ABSTRACT FROM AUTHOR]

Aggregatibacter actinomycetemcomitans is a perio-pathogenic bacteria that has long been associated with localized aggressive periodontitis. The mechanisms of its pathogenicity have been studied in humans and preclinical experimental models. Although different serotypes of A. actinomycetemcomitans have differential virulence factor expression, A. actinomycetemcomitans cytolethal distending toxin (CDT), leukotoxin, and lipopolysaccharide (LPS) have been most extensively studied in the context of modulating the host immune response. Following colonization and attachment in the oral cavity, A. actinomycetemcomitans employs CDT, leukotoxin, and LPS to evade host innate defense mechanisms and drive a pathophysiologic inflammatory response. This supra-physiologic immune response state perturbs normal periodontal tissue remodeling/turnover and ultimately has catabolic effects on periodontal tissue homeostasis. In this review, we have divided the host response into two systems: non-hematopoietic and hematopoietic. Non-hematopoietic barriers include epithelium and fibroblasts that initiate the innate immune host response. The hematopoietic system contains lymphoid and myeloid-derived cell lineages that are responsible for expanding the immune response and driving the pathophysiologic inflammatory state in the local periodontal microenvironment. Effector systems and signaling transduction pathways activated and utilized in response to A. actinomycetemcomitans will be discussed to further delineate immune cell mechanisms during A. actinomycetemcomitans infection. Finally, we will discuss the osteo-immunomodulatory effects induced by A. actinomycetemcomitans and dissect the catabolic disruption of balanced osteoclast-osteoblast-mediated bone remodeling, which subsequently leads to net alveolar bone loss. [ABSTRACT FROM AUTHOR]

During periodontitis, alveolar bone resorption is associated with activation of T helper type 17 (Th17) lymphocytes and receptor activator of nuclear factor-κB ligand (RANKL) -induced osteoclasts. We previously reported that serotype b of Aggregatibacter actinomycetemcomitans has a higher capacity to trigger Th17-type differentiation and function in activated T lymphocytes and its lipopolysaccharide is a more potent immunogen compared with the other serotypes. This study aimed to investigate whether serotype b of A. actinomycetemcomitans induces higher Th17-associated RANKL production, RANKL-induced osteoclast activation, and antigen-specific memory T lymphocyte proliferation. On naive CD4(+) T lymphocytes stimulated with autologous dendritic cells primed with different A. actinomycetemcomitans serotypes, RANKL production, T-bet, GATA-3, RORC2 and Foxp3 expression, RORC2/RANKL intracellular double-expression, TRAP(+) osteoclast activation, and bone resorption were quantified. The frequency of proliferating memory T lymphocytes in response to A. actinomycetemcomitans serotypes was determined in periodontitis and healthy subjects. Naive CD4(+) T lymphocytes stimulated by serotype b-primed dendritic cells elicited higher levels of RANKL, RORC2, TRAP(+) osteoclasts, and bone resorption than the same cells stimulated with the other serotypes. RANKL positively correlated and co-expressed with RORC2. Memory T lymphocytes responding to serotype b were more frequently detected in periodontitis patients than healthy subjects. These results indicate that serotype b of A. actinomycetemcomitans is associated with higher production of RANKL and these increased levels are associated with Th17 lymphocyte induction, osteoclast activation, and bone resorption. [ABSTRACT FROM AUTHOR]

The leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans kills host immune cells, allowing the bacterium to establish an ecological niche in the upper aerodigestive tract of its human host. The interaction of LtxA with human immune cells is both complex and multifaceted, involving membrane lipids as well as cell-surface proteins. In the initial encounter with the host cell, LtxA associates with lymphocyte function-associated antigen-1, a cell surface adhesion glycoprotein. However, we have also demonstrated that the toxin associates strongly with the plasma membrane lipids, specifically cholesterol. This association with cholesterol is regulated by a cholesterol recognition amino acid consensus (CRAC) motif, with a sequence of (334) LEEYSKR(340), in the N-terminal region of the toxin. Here, we have demonstrated that removal of cholesterol from the plasma membrane or mutation of the LtxA CRAC motif inhibits the activity of the toxin in THP-1 cells. To inhibit LtxA activity, we designed a short peptide corresponding to the CRAC(336) motif of LtxA (CRAC(336WT)). This peptide binds to cholesterol and thereby inhibits the toxicity of LtxA in THP-1 cells. Previously, we showed that this peptide inhibits LtxA toxicity against Jn.9 (Jurkat) cells, indicating that peptides derived from the cholesterol-binding site of LtxA may have a potential clinical applicability in controlling infections of repeats-in-toxin-producing organisms. [ABSTRACT FROM AUTHOR]

Objective This study aimed to evaluate clinical and microbiological effects of systemic azithromycin ( AZM) in adjunct to nonsurgical periodontal therapy ( NSPT; or scaling root planing - SRP) in treatment of Aggregatibacter actinomycetemcomitans associated periodontitis ( AAAP). Methods and materials Seventy individuals with moderate to severe periodontitis and subgingival detection of A. actinomycetemcomitans were randomly allocated to two groups. Thirty-five individuals were allocated to full mouth SRP+AZM (500 mg oral delivery ( OD) × 3 days) while 35 individuals were allocated to SRP+Placebo ( OD × 3 days) group. The clinical variables evaluated were probing depth ( PD), clinical attachment level ( CAL), gingival index ( GI), plaque index ( PI), and percent bleeding on probing sites (% BOP), while microbiologic variables included percentage of subjects positive for A. actinomycetemcomitans at baseline, 3, 6, and 12 months. Results The AZM group showed statistically significant reduction in mean PD (2.91 ± 0.88 mm) as compared to placebo (1.51 ± 0.98 mm) ( P < 0.001), while CAL gain was significant in the AZM group (2.71 ± 1.15 mm) as compared to the placebo group (1.71 ± 1.29 mm) ( P < 0.001). There was also a statistically significant reduction in the number of subjects positive for A. actinomycetemcomitans in the AZM group ( P < 0.0001). Conclusion Azithromycin was found to significantly improve the clinical and microbiological parameters in AAAP individuals. [ABSTRACT FROM AUTHOR]

Background and Objective Sphingosine-1-phosphate ( S1 P) is a bioactive sphingolipid, which is generated by activation of sphingosine kinase ( SK) 1 and/or 2 in most mammalian cells with various stimuli, including the oral pathogen Aggregatibacter actinomycetemcomitans. S1 P signaling has been shown to regulate the migration of monocytes and macrophages (osteoclast precursors) from the circulation to bone tissues and affect bone homeostasis. We aimed to determine the effects of SK1 deficiency on S1 P generation, proinflammatory cytokine production, chemotaxis of monocytes and macrophages, and periodontitis induced by A. actinomycetemcomitans. Material and Methods Murine bone marrow-derived monocytes and macrophages ( BMMs) from SK1 knockout ( KO) mice or wild-type ( WT) mice were either untreated or exposed to A. actinomycetemcomitans. The mRNA levels of SK1, SK2 and intracellular sphingolipid levels were quantified. In addition, murine WT BMMs were treated with vehicle, S1 P, with or without A. actinomycetemcomitans and the mRNA levels of cyclooxygenase 2 (COX-2), interleukin ( IL)-1β, IL-6 and tumor necrosis factor ( TNF) were quantified. The protein levels of prostaglandin E2, IL-1β, IL-6 and TNF-α were quantified in the cell media of SK1 KO BMMs or WT BMMs with or without bacterial stimulation. Furthermore, a transwell migration assay was performed and the number of migrated WT BMMs in the presence of vehicle, bacteria-stimulated media, with or without S1 P was quantified. Finally, in vivo studies were performed on SK1 KO and WT mice by injecting either phosphate-buffered saline or A. actinomycetemcomitans in the periodontal tissues. The mice maxillae were scanned by micro-computed tomography, and alveolar bone volume was analyzed. The number of periodontal leukocytes and osteoclasts were quantified in maxillary tissue sections. Results SK1 mRNA levels significantly increased after A. actinomycetemcomitans stimulation in murine WT BMMs, but were undetectable in SK1 KO BMMs. Deficiency of SK1 in murine BMMs resulted in decreased S1 P generation induced by A. actinomycetemcomitans as compared with WT BMMs. Additionally, low levels of S1 P (≤ 1 μ m) did not have a significant impact on the mRNA production of COX-2, IL-1β, IL-6 and TNF in murine BMMs with or without the presence of A. actinomycetemcomitans. There were no significant differences in prostaglandin E2, IL-1β, IL-6 and TNF-α protein levels in the media between SK1 KO BMMs and WT BMMs with or without bacterial stimulation. Importantly, low levels of S1 P (≤ 1 μ m) dose-dependently promoted the chemotaxis of BMMs. The bacteria-stimulated media derived from SK1 BMMs significantly reduced the chemotaxis response compared with WT control. Finally, SK1 KO mice showed significantly attenuated alveolar bone loss stimulated by A. actinomycetemcomitans compared with WT mice treated with A. actinomycetemcomitans. Histological analysis of periodontal tissue sections revealed that SK1 KO mice treated with A. actinomycetemcomitans significantly reduced the number of infiltrated periodontal leukocytes and mature osteoclasts attached on the alveolar bone compared with WT mice. Conclusion Our studies support that SK1 and S1 P play an important role in the inflammatory bone loss response induced by the oral pathogen A. actinomycetemcomitans. Reducing S1 P generation by inhibiting SK1 has the potential as a novel therapeutic strategy for periodontitis and other inflammatory bone loss diseases. [ABSTRACT FROM AUTHOR]

Background There is little consensus on the most appropriate cement to use when restoring a cement-retained, implant-supported restoration. One consideration should be the interaction of pathogenic oral bacteria with restorative cements. Purpose To determine how oral bacteria associated with peri-implant disease grow in the presence of implant cements. Materials and Methods Five test cements with varying composition (zinc oxide-eugenol [ TBO], eugenol-free zinc oxide [ TBNE], zinc orthophosphate [ FL], and two resin cements [ PIC and ML]) were used to fabricate specimen disks. The disks were submerged in bacterial suspensions of either Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, or P orphyromonas gingivalis. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures ( OD600). Positive controls (media and bacteria without cement disks) and negative controls (media alone) were similarly evaluated. The mean and standard deviations ( SD) were calculated for planktonic growth from three separate experiments. ANOVA statistical analysis with post hoc Tukey tests was performed where differences existed ( p < .05). Selected cement disks ( TBO and ML) were further examined for bacterial biofilm growth. Surface bacteria were removed and grown on agar media, and colony-forming units ( CFUs) were quantified. Results Planktonic growth for both A . actinomycetemcomitans and P . gingivalis was significantly inhibited ( p < .05) when grown in the presence of cement disks consisting of TBNE, PIC, FL, and TBO. In contrast, neither of these bacteria displayed growth inhibition in the presence of ML cement disks. F . nucleatum growth was also significantly inhibited by PIC, FL. and TBO ( p < .05), but not by ML and TBNE cement disks. CFU counts for the biofilm study for TBO gave minimal and, in some instances, no bacterial adherence and growth, in contrast to ML, which supported substantially greater bacterial biofilm growth. Conclusion Cements display differing abilities to inhibit both planktonic and biofilm bacterial growth. Cements with the ability to reduce planktonic or biofilm growth of the test bacteria may be advantageous in reducing peri-implant disease. Understanding the microbial growth-inhibiting characteristics of different cement types should be considered important in the selection criteria. [ABSTRACT FROM AUTHOR]

Background and Objective Based on lipopolysaccharide (LPS) antigenicity, different Aggregatibacter actinomycetemcomitans serotypes have been described. Serotype b strains have demonstrated a stronger capacity to trigger cytokine production on dendritic cells (DCs). As DCs regulate the development of T-lymphocyte lineages, the objective of this investigation was to study the response of T lymphocytes after being stimulated with autologous DCs primed with different bacterial strains belonging to the most prevalent serotypes of A. actinomycetemcomitans in humans: a-c. Material and Methods Human DCs were primed with increasing multiplicity of infection (10−1-102) or the purified LPS (10-50 ng/mL) of A. actinomycetemcomitans serotypes a-c and then used to stimulate autologous naïve CD4+ T lymphocytes. The T-helper (Th) type 1, Th2, Th17 and T-regulatory transcription factors T-bet, GATA-3, RORC2 and Foxp3, which are the master-switch genes implied in their specific differentiation, as well as T-cell phenotype-specific cytokine patterns were quantified by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. In addition, the intracellular expression of T-bet/interferon-γ, GATA-3/interleukin-4, RORC2/interleukin-17A and Foxp3/transforming growth factor-β1 was analysed by double staining and flow cytometry. Results All the A. actinomycetemcomitans serotypes led to T-lymphocyte activation; however, when T lymphocytes were stimulated with DCs primed with the A. actinomycetemcomitans serotype b strain or their purified LPS, higher levels of Th1- and Th17-associated transcription factors and cytokines were detected compared with similar experiments with the other serotypes. Conclusion These results demonstrate that serotype b of A. actinomycetemcomitans has a higher capacity of trigger Th1 and Th17 phenotype and function and it was demonstrated that their LPS is a more potent immunogen compared with the other serotypes. [ABSTRACT FROM AUTHOR]

Objectives To determine in vivo association between Aggregatibacter actinomycetemcomitans ( Aa) and Streptococcus mutans ( Sm) in aggressive periodontitis patients (AgP) and the in vitro influence on Sm of saliva and of Aa strains isolated from individual Aa-positive patients. Materials and Methods Clinical indices and saliva samples were taken from 30 AgP patients. Aa and mutans streptococci levels were determined. Antibacterial effect of saliva from 12 Aa-positive patients, and their individual Aa strain, was checked turbidimetrically in vitro on Sm. Results Aa salivary level was inversely correlated with levels of mutans streptococci and directly correlated with pockets of ≥7 mm. During exponential growth phase: (i) All Aa-positive and Aa-negative saliva samples showed no significant influence on Sm growth. (ii) Each individually isolated Aa strain presented significant inhibitory effect on Sm growth. During stationary growth phase, all the above demonstrated an inhibitory effect on Sm growth, with significantly greater influence of Aa individual strains. Conclusion Saliva of each AgP Aa-positive subject had an inhibitory effect on Sm growth, which is most likely derived from Aa bacterial physiology. This research raises the possibility that suppression of Aa due to periodontal treatment may increase Sm levels and hence caries incidence. [ABSTRACT FROM AUTHOR]

Aggregatibacter actinomycetemcomitans Qse BC regulates its own expression and is essential for biofilm growth and virulence. However, the signal that activates the QseC sensor has not been identified and the qse BC regulon has not been defined. In this study, we show that QseC is activated by catecholamine hormones and iron but not by either component alone. Activation of QseC requires an EYRDD motif in the periplasmic domain of the sensor and site-specific mutations in EYRDD or the deletion of the periplasmic domain inhibits catecholamine/iron-dependent induction of the ygiW-qse BC operon. Catecholamine/iron-dependent induction of transcription also requires interaction of the QseB response regulator with its binding site in the ygiW-qse BC promoter. Whole genome microarrays were used to compare gene expression profiles of A. actinomycetemcomitans grown in a chemically defined medium with and without catecholamine and iron supplementation. Approximately 11.5% of the A. actinomycetemcomitans genome was differentially expressed by at least two-fold upon exposure to catecholamines and iron. The expression of ferritin was strongly induced, suggesting that intracellular iron storage capacity is increased upon Qse BC activation. Consistent with this, genes encoding iron binding and transport proteins were down-regulated by Qse BC. Strikingly, 57% of the Qse BC up-regulated genes (56/99) encode proteins associated with anaerobic metabolism and respiration. Most of these up-regulated genes were recently reported to be induced during in vivo growth of A. actinomycetemcomitans. These results suggest that detection of catecholamines and iron by Qse BC may alter the cellular metabolism of A. actinomycetemcomitans for increased fitness and growth in an anaerobic host environment. [ABSTRACT FROM AUTHOR]

Aim: Generalized aggressive periodontitis (GAP) is a severe and multifactorial disease in which a familial aggregation and a specific microbiological profile have been suggested. Thus, this case-control study evaluated the clinical and subgingival microbial profile of GAP subjects and their families compared to healthy families. Methods: Fifteen families with parents presenting periodontal health and 15 with parents with a history of GAP were selected. Each family should have at least one child between 6 and 12 years old. Plaque index (PI), gingival index (GI), and periodontal probing depth (PPD), as well as Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans (Aa) amounts (by qPCR), were assessed from all subjects. Results: Children of GAP families showed a higher PI, GI, and PPD when compared to children of healthy families (p ≤0.05). A higher frequency of detection and amounts of Aa was observed in GAP children compared to children of healthy families (p ≤0.05). Moreover, a significant association between Aa amounts and gingival bleeding was observed in children (p ≤0.05, r = 0.37). Conclusion: Children from GAP families have worst clinical conditions, i.e. higher levels of PI, GI, and PPD, a more pathogenic microbiological profile, and the amount of Aa are associated with a higher marginal inflammation. [ABSTRACT FROM AUTHOR]

Background and Objective Periodontal diseases are often induced by periodontopathogens, which are always exposed to certain innate immune factors in gingival crevicular fluid, including human β-defensin-2 ( hBD-2). This study aims to investigate the relationship among periodontopathogens, clinical parameters and hBD-2 expression. Material and Methods Thirty-two healthy controls, 42 patients with chronic gingivitis and 95 patients with chronic periodontitis were recruited in Guangxi, China. Bleeding index, probing depth and clinical attachment level were measured for all teeth including mesiobuccal, buccal, disobuccal, mesiolingual, lingual, disolingual six sites of all patient. Gingival crevicular fluid samples were collected from the study sites. The prevalence and copy numbers (CN) of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, Tannerella forsythia and total bacteria in gingival crevicular fluid were quantified by real-time PCR. The hBD-2 concentration in gingival crevicular fluid was measured by ELISA. Results Both the prevalence and the CN of A. actinomycetemcomitans, P. gingivalis, T. denticola and T. forsythia were higher in patients with chronic periodontitis than in healthy controls and patients with chronic gingivitis; however, there was no significant difference in the prevalence of P. intermedia among the three study groups, and the highest CN was found in patients with chronic gingivitis, rather than in patients with chronic periodontitis. The loads of P. gingivalis, P. intermedia, T. denticola and total bacteria were positively related to probing depth, bleeding index and clinical attachment level. The concentration of hBD-2 in gingival crevicular fluid was higher in patients with chronic gingivitis and in patients with chronic periodontitis than in healthy controls. In addition, the hBD-2 concentration was positively related to the CN of P. gingivalis, T. forsythia and total bacteria, as well as to bleeding index and probing depth. Conclusion The prevalence, composition and CN of periodontopathogens were closely related to the severity of periodontal disease, and the red complex was related to the severity of clinical symptoms of periodontal diseases. The concentration of hBD-2 in gingival crevicular fluid from periodontal disease sites was higher than that in gingival crevicular fluid from healthy sites, which suggests that hBD-2 expression might be up-regulated by periodontopathogens. [ABSTRACT FROM AUTHOR]

Aim The aim of the present study was to analyze the occurrence of Porphyromonas gingivalis ( P. gingivalis), Tannerella forsythia ( T. forsythia), Treponema denticola ( T. denticola), and Aggregatibacter actinomycetemcomitans ( A. actinomycetemcomitans) in patients with diabetes. Methods Periodontal and diabetic parameters and subgingival biofilm samples were obtained from 60 patients with diabetes and 62 patients without diabetes. By using polymerase chain reaction, the prevalence of red complex microorganisms ( P. gingivalis, T. forsythia, and T. denticola) and A. actinomycetemcomitans were determined. Descriptive and non-parametric statistical analyses between groups were performed (Kruskal-Wallis, Mann-Whitney U-test, and Fisher's exact test). Results Patients with diabetes presented significantly higher periodontal attachment loss levels compared to patients without diabetes. Red complex microorganisms were detected in lower frequencies in patients with diabetes. The detection of A. actinomycetemcomitans was higher in patients with diabetes and periodontitis compared to systemically-healthy patients without periodontitis ( P < 0.05). P. gingivalis was associated with periodontitis in non-diabetic patients ( P < 0.05), whereas A. actinomycetemcomitans was associated with periodontitis in diabetic patients ( P < 0.05). Conclusions The findings of the present study indicate that there might be differences in the subgingival microbiota between diabetic and non-diabetic patients. In addition, P. gingivalis and A. actinomycetemcomitans were associated with periodontitis in patients without diabetes and patients with diabetes, respectively. [ABSTRACT FROM AUTHOR]

Background: Aggregatibacter actinomycetemcomitans resists killing by neutrophils and is inhibited by azithromycin (AZM) and amoxicillin (AMX). AZM actively concentrates inside host cells, whereas AMX enters by diffusion. The present study is conducted to determine whether AZM is more effective than AMX at enhancing phagocytic killing of A. actinomycetemcomitans by neutrophils. Methods: Killing assays were conducted in the presence of either 2 (µg/rnL AZM or 16 (µg/mL AMX (equipotent against A. actinomycetemcomitans). Neutrophils were loaded by incubation with the appropriate antibiotic. Opsonized A. actinomycetemcomitans strain Y4 was incubated with the indicated antibiotic alone, with loaded neutrophils and antibiotic, or with control neutrophils (without antibiotic) at multiplicities of infection (MOIs) of 30 and 90 bacteria per neutrophil. Results: Meutrophil incubation with 2 µg/mL AZM yielded an intracellular concentration of 10 (xg/mL. At an MOI of 30, neutrophils loaded with AZM failed to kill significantly more bacteria than control neutrophils during the 60- and 90-minute assay periods. At an MOI of 90, neutrophils loaded with AZM killed significantly more bacteria than either AZM alone or control neutrophils during 60- and 90-minute incubations (P <0.05), and killed significantly more bacteria after 90 minutes than the sum of the killing produced by AZM alone or neutrophils alone. Neutrophils incubated with AMX under identical conditions also killed significantly more bacteria than either AMX alone or control neutrophils, but there was no evidence of synergism between AMX and neutrophils. Conclusions: Neutrophils possess a concentrative transport system for AZM that may enhance killing of A. actinomycetemcomitans. Its effects are most pronounced when neutrophils are greatly outnumbered by bacteria. [ABSTRACT FROM AUTHOR]

Background: Different serotypes of Aggregatibacter actinomycetemcomitans and Porphyromonas gingiualis have been shown to induce differential dendritic cell (DC) responses. This study investigates whether cytokine and CC-chemokine receptor (CCR) production by DCs stimulated with different serotypes of A. actinomycetemcomitans or P. gingiualis is Toll-like receptor 2 (TLR2) and/or TLR4 dependent. Methods: DCs were obtained from healthy individuals and primed at a multiplicity of infection (MO1) of 10² with different A. actinomycetemcomitans or P. gingiualis serotypes in the presence or absence of anti-TLR2 or anti-TLR4 blocking antibodies. TLR2 and TLR4 expression, CCR5 and CCR6 expression, and interleukin (IL)-1β, IL-10, IL-12, and IL-23 expression and secretion were quantified by flow cytometry, real-time reverse-transcription polymerase chain reaction, and enzyme-linked immunosorbent assay. Results: When DCs were stimulated with serotype b of A. actinomycetemcomitans or serotype K1 of P. gingivalis, higher levels of TLR2 or TLR4, respectively, were detected compared to DCs stimulated with the other serotypes. Similarly, higher levels of cytokines and CCRs were detected in serotype b- or sero-type K1-primed DCs compared to the others, and these increased levels positively correlated with levels of TLR2 or TLR4. When TLR2 signaling was blocked using a specific anti-TLR2 monoclonal antibody, serotype b-induced cytokine and CCR expression was inhibited; when TLR4 signaling was blocked, sero-type K1-induced response was inhibited. Conclusions: These results demonstrate that the variability of secretion of cytokines and expression of CCRs detected in DCs stimulated with different serotypes of A. actinomycetemcomitans or P. gingiualis is TLR2 or TLR4 dependent, respectively. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the influence of smoking on clinical, microbiological and immunological parameters in young adult with stage III-IV Grade C periodontitis after full-mouth ultrasonic debridement (FMUD) associated with Amoxicillin and Metronidazole (AMX + MTZ), comparing smokers (PerioC-Y-Smk) with non-smokers (PerioC-Y-NSmk)., Materials and Methods: Fifteen PerioC-Y-NSmk and 14 PerioC-Y-Smk patients underwent FMUD associated with AMX + MTZ for 10 days. All parameters were collected at baseline and 3 and 6 months after treatment. Plaque index (PI), bleeding on probing (BoP), probing depth (PD), clinical attachment level (CAL)- the primary variable-, and gingival recession (GR) were clinically assessed. The impact of PI on CAL change at 6-month was verified by a regression analysis. Samples of the subgingival biofilm was collected for detection of levels of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P.gingivalis), Tannerella forsythia (T. forsythia), and Fusobacterium nucleatum ssp (F. nucleatum), and were analyzed by real-time qPCR; gingival crevicular fluid was collected for detection of levels of interleukin (IL)-1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, which were analyzed using an enzyme immunoassay., Results: PerioC-Y-Smk had significantly higher PI, BOP, and GR at baseline compared to non-smokers (p < .05). PerioC-Y-Smk presented higher PD, CAL, and GR at 3 and 6 months (p < .05) compared with PerioC-Y-NSmk in the same periods; PI negatively affected CAL gain in PerioC-Y-NSmk at 6-month follow-up (p = .052) and did not impact on clinical response in PerioC-Y-Smk (p = .882). Lower levels of IFN-γ, IL1-β, and IL-4 were observed at 3 months in the PerioC-Y-NSmk (p < .05) compared with PerioC-Y-Smk. Lower proportions of P. gingivalis were observed in PerioC-Y-NSmk at baseline and at 3 months (p < .05) and lower proportions of F. nucleatum were observed at 6 months, in the PerioC-Y-NSmk (p < .05)., Conclusions: PerioC-Y-Smk presents an unfavorable clinical, microbiological, and immunological response after 3 and 6 months after FMUD associated with AMX + MTZ., Clinical Relevance: Smoking worsens periodontal condition of young treated adults presenting stage III/IV Grade C periodontitis., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)