Associations between periodontitis and serum anti-malondialdehyde-acetaldehyde antibody concentrations in rheumatoid arthritis: A case-control study.

BACKGROUND: Malondialdehyde-acetaldehyde (MAA) adducts lead to generation of anti-MAA autoantibodies and have been independently identified in inflamed periodontal and rheumatoid arthritis (RA) tissues. This study evaluates serum samples from RA cases and osteoarthritis (OA) controls to quantify associations between periodontal clinical measures, alveolar bone loss (ABL), and anti-Porphyromonas gingivalis, anti-Prevotella intermedia, and anti-Fusobacterium nucleatum antibody concentrations with anti-MAA antibody concentrations. METHODS: Participants (n = 284 RA cases, n = 330 OA controls) underwent periodontal clinical assessments and ABL measurements. Serum immunoglobulin (Ig) A, IgG, and IgM anti-MAA and serum IgG antibacterial antibody concentrations were quantified by enzyme-linked immunosorbent assay (ELISA). Analyses utilized simple linear regression and multivariable adjusted models. RESULTS: No significant associations of periodontal clinical measures with serum anti-MAA were found. Moderate (p = 0.038 and p = 0.036, respectively) and high ABL (p = 0.012 and p = 0.014, respectively) in RA cases (but not in OA) were positively associated with IgG and IgM anti-MAA. Anti-P. gingivalis and anti-P. intermedia antibody concentrations were positively associated with IgA (p = 0.001 for both), IgG (p = 0.007 and p = 0.034, respectively), and IgM anti-MAA antibody concentrations (p < 0.001 and p = 0.020, respectively), while anti-F. nucleatum was positively associated with IgG anti-MAA (p = 0.042), findings that were similar across groups. CONCLUSIONS: A positive association was demonstrated between ABL and serum IgG and IgM anti-MAA antibody concentrations that was unique to RA and not observed in OA. Serum anti-P. gingivalis, anti-P. intermedia, and anti-F. nucleatum antibody concentrations displayed significant associations with anti-MAA antibody in both groups. These findings suggest MAA may play a role in the interrelationship between the periodontium and RA.

Prevotella intermedia boosts OSCC progression through ISG15 upregulation: a new target for intervention.

PURPOSE: Periodontitis-associated bacteria, such as Porphyromonas gingivalis and Fusobacterium nucleatum, are closely linked to the risk of oral squamous cell carcinoma (OSCC). Emerging studies have indicated that another common periodontal pathogen, Prevotella intermedia (P. intermedia), is enriched in OSCC and could affect the occurrence and progression of OSCC. Our aim is to determine the effects of P. intermedia on the progression of OSCC and the role of antibiotics in reversing these effects. METHODS: In this study, a murine xenograft model of OSCC was established, and the mice were injected intratumorally with PBS (control group), P. intermedia (P.i group), or P. intermedia combined with an antibiotic cocktail administration (P.i + ABX group), respectively. The effects of P. intermedia and ABX administration on xenograft tumor growth, invasion, angiogenesis, and metastasis were investigated by tumor volume measurement and histopathological examination. Enzyme-linked immunosorbent assay (ELISA) was used to investigate the changes in serum cytokine levels. Immunohistochemistry (IHC) was adopted to analyze the alterations in the levels of inflammatory cytokines and infiltrated immune cells in OSCC tissues of xenograft tumors. Transcriptome sequencing and analysis were conducted to determine differential expression genes among various groups. RESULTS: Compared with the control treatment, P. intermedia treatment significantly promoted tumor growth, invasion, angiogenesis, and metastasis, markedly affected the levels of inflammatory cytokines, and markedly altered M2 macrophages and regulatory T cells (Tregs) infiltration in the tumor microenvironment. However, ABX administration clearly abolished these effects of P. intermedia. Transcriptome and immunohistochemical analyses revealed that P. intermedia infection increased the expression of interferon-stimulated gene 15 (ISG15). Correlation analysis indicated that the expression level of ISG15 was positively correlated with the Ki67 expression level, microvessel density, serum concentrations and tissue expression levels of inflammatory cytokines, and quantities of infiltrated M2 macrophages and Tregs. However, it is negatively correlated with the quantities of infiltrated CD4+ and CD8+ T cells. CONCLUSION: In conclusion, intratumoral P. intermedia infection aggravated OSCC progression, which may be achieved through upregulation of ISG15. This study sheds new light on the possible pathogenic mechanism of intratumoral P. intermedia in OSCC progression, which could be a prospective target for OSCC prevention and treatment.

Heat-killed Prevotella intermedia promotes the progression of oral squamous cell carcinoma by inhibiting the expression of tumor suppressors and affecting the tumor microenvironment.

BACKGROUND: Oral microbial dysbiosis contributes to the development of oral squamous cell carcinoma (OSCC). Our previous study showed that Prevotella intermedia (P. intermedia) were enriched in the oral mucosal surface, plaque, and saliva of patients with OSCC. Intratumoral microbiome could reshape the immune system and influence the development of various tumors. However, the invasion status of human OSCC tissues by P. intermedia and the pathway through which intratumoral P. intermedia potentiates tumor progression remain unexplored. METHODS: P. intermedia in human OSCC or normal tissues was detected by FISH. A mouse OSCC cell line SCC7 was adopted to investigate the effects of heat-killed P. intermedia treatment on cell proliferation, invasion, and cytokine release by using CCK-8 assay, transwell invasion assay and ELISA. Moreover, we established a mouse transplanted tumor model by using SCC7 cells, injected heat-killed P. intermedia into tumor tissues, and investigated the effects of heat-killed P. intermedia on tumor growth, invasion, cytokine levels, immune cell infiltrations, and expression levels by using gross observation, H&E staining, ELISA, immunohistochemistry, mRNA sequencing, and transcriptomic analysis. RESULTS: Our results indicated that P. intermedia were abundant in OSCC and surrounding muscle tissues. Heat-killed P. intermedia promoted SCC7 cell proliferation, invasion and proinflammatory cytokine secretions, accelerated transplanted tumor growth in mice, exacerbate muscle and perineural invasion of OSCC, elevated the serum levels of IL-17A, IL-6, TNF-α, IFN-γ, and PD-L1, induced Treg cells M2 type macrophages in mouse transplanted tumors. The data of transcriptomic analysis revealed that heat-killed P. intermedia increased the expression levels of inflammatory cytokines and chemokines while reduced the expression levels of some tumor suppressor genes in mouse transplanted tumors. Additionally, IL-17 signaling pathway was upregulated whereas GABAergic system was downregulated by heat-killed P. intermedia treatment. CONCLUSIONS: Taken together, our results suggest that P. intermedia could inhibit the expression of tumor suppressors, alter the tumor microenvironment, and promote the progression of OSCC.

Ultrastructural and glycoproteomic characterization of Prevotella intermedia: Insights into O-glycosylation and outer membrane vesicles.

Prevotella intermedia, a Gram-negative bacterium from the Bacteroidota phylum, is associated with periodontitis. Other species within this phylum are known to possess the general O-glycosylation system. The O-glycoproteome has been characterized in several species, including Tannerella forsythia, Porphyromonas gingivalis, and Flavobacterium johnsoniae. In our study, we used electron cryotomography (cryoET) and glycoproteomics to reveal the ultrastructure of P. intermedia and characterize its O-glycoproteome. Our cryoET analysis unveiled the ultrastructural details of the cell envelope and outer membrane vesicles (OMVs) of P. intermedia. We observed an electron-dense surface layer surrounding both cells and OMVs. The OMVs were often large (>200 nm) and presented two types, with lumens being either electron-dense or translucent. LC-MS/MS analyses of P. intermedia fractions led to the identification of 1655 proteins, which included 62 predicted T9SS cargo proteins. Within the glycoproteome, we identified 443 unique O-glycosylation sites within 224 glycoproteins. Interestingly, the O-glycosylation motif exhibited a broader range than reported in other species, with O-glycosylation found at D(S/T)(A/I/L/M/T/V/S/C/G/F/N/E/Q/D/P). We identified a single O-glycan with a delta mass of 1531.48 Da. Its sequence was determined by MS2 and MS3 analyses using both collision-induced dissociation and high-energy collisional dissociation fragmentation modes. After partial deglycosylation with trifluoromethanesulfonic acid, the O-glycan sequence was confirmed to be dHex-dHex-HexNAc (HPO3 -C6 H12 O5 )-dHex-Hex-HexA-Hex(dHex). Bioinformatic analyses predicted the localization of O-glycoproteins, with 73 periplasmic proteins, 53 inner membrane proteins, 52 lipoproteins, 26 outer membrane proteins, and 14 proteins secreted by the T9SS.

Hemophore-like proteins of the HmuY family in the oral and gut microbiome: unraveling the mystery of their evolution.

SUMMARY: Heme (iron protoporphyrin IX, FePPIX) is the main source of iron and PPIX for host-associated pathogenic bacteria, including members of the Bacteroidota (formerly Bacteroidetes) phylum. Porphyromonas gingivalis, a keystone oral pathogen, uses a unique heme uptake (Hmu) system, comprising a hemophore-like protein, designated as the first member of the novel HmuY family. Compared to classical, secreted hemophores utilized by Gram-negative bacteria or near-iron transporter domain-based hemophores utilized by Gram-positive bacteria, the HmuY family comprises structurally similar proteins that have undergone diversification during evolution. The best characterized are P. gingivalis HmuY and its homologs from Tannerella forsythia (Tfo), Prevotella intermedia (PinO and PinA), Bacteroides vulgatus (Bvu), and Bacteroides fragilis (BfrA, BfrB, and BfrC). In contrast to the two histidine residues coordinating heme iron in P. gingivalis HmuY, Tfo, PinO, PinA, Bvu, and BfrA preferentially use two methionine residues. Interestingly, BfrB, despite conserved methionine residue, binds the PPIX ring without iron coordination. BfrC binds neither heme nor PPIX in keeping with the lack of conserved histidine or methionine residues used by other members of the HmuY family. HmuY competes for heme binding and heme sequestration from host hemoproteins with other members of the HmuY family to increase P. gingivalis competitiveness. The participation of HmuY in the host immune response confirms its relevance in relation to the survival of P. gingivalis and its ability to induce dysbiosis not only in the oral microbiome but also in the gut microbiome or other host niches, leading to local injuries and involvement in comorbidities.

Tumor-derived Prevotella intermedia aggravates gastric cancer by enhancing Perilipin 3 expression.

The indigenous microbial milieu within tumorous tissues exerts a pivotal influence on the genesis and advancement of gastric cancer (GC). This investigation scrutinizes the functions and molecular mechanisms attributed to Prevotella intermedia in the malignant evolution of GC. Isolation of P. intermedia from paired GC tissues was undertaken. Quantification of P. intermedia abundance in 102 tissues was accomplished using quantitative real-time PCR (qRT-PCR). Assessment of the biological effects of P. intermedia on GC cells was observed using culture medium supernatant. Furthermore, the protein profile of GC cells treated with tumor-derived P. intermedia was examined through label-free protein analysis. The functionality of perilipin 3 (PLIN3) was subsequently confirmed using shRNA. Our investigation revealed that the relative abundance of P. intermedia in tumor tissues significantly surpassed that of corresponding healthy tissues. The abundance of P. intermedia exhibited correlations with tumor differentiation (p = 0.006), perineural invasion (p = 0.004), omentum majus invasion (p = 0.040), and the survival duration of GC patients (p = 0.042). The supernatant derived from tumor-associated P. intermedia bolstered the proliferation, clone formation, migration, and invasion of GC cells. After indirect co-cultivation with tumor-derived P. intermedia, dysregulation of 34 proteins, including PLIN3, was discerned in GC cells. Knockdown of PLIN3 mitigated the malignancy instigated by P. intermedia in GC cells. Our findings posit that P. intermedia from the tumor microenvironment plays a substantial role in the malignant progression of GC via the modulation of PLIN3 expression. Moreover, the relative abundance of P. intermedia might serve as a potential biomarker for the diagnosis and prognosis of GC.

Effect of nitro-conjugated linoleic acid on the inflammatory response of murine macrophages activated with lipopolysaccharide derived from Prevotella intermedia.

Nitro-conjugated linoleic acid (NO2-CLA) has been observed to manifest salutary signaling responses, including anti-inflammatory and antioxidant properties. Here, the authors have explored the influence and underlying mechanisms of NO2-CLA on the proinflammatory reaction of murine macrophages that were challenged with lipopolysaccharide (LPS) derived from Prevotella intermedia, a putative periodontopathic bacterium. Treatment of LPS-activated RAW264.7 cells with NO2-CLA notably dampened the secretion of iNOS-derived NO, IL-1ß and IL-6 as well as their gene expressions and significantly enhanced the markers for M2 macrophage polarization. NO2-CLA promoted the HO-1 expression in cells challenged with LPS, and tin protoporphyrin IX, an HO-1 inhibitor, significantly reversed the NO2-CLA-mediated attenuation of NO secretion, but not IL-1ß or IL-6. We found that cells treated with NO2-CLA significantly increased mRNA expression of PPAR-γ compared to control cells, and NO2-CLA significantly reverted the decrease in PPAR-γ mRNA caused by LPS. Nonetheless, antagonists to PPAR-γ were unable to reverse the NO2-CLA-mediated suppression of inflammatory mediators. In addition, NO2-CLA did not alter the p38 and JNK activation elicited by LPS. Both NF-κB reporter activity and IκB-α degradation caused by LPS were notably diminished by NO2-CLA. NO2-CLA was observed to interrupt the nuclear translocation and DNA binding of p50 subunits caused by LPS with no obvious alterations in p65 subunits. Further, NO2-CLA attenuated the phosphorylation of STAT1/3 elicited in response to LPS. We propose that NO2-CLA could be considered as a possible strategy for the therapy of periodontal disease, although additional researches are certainly required to confirm this.

Antibacterial Efficacy of Dual-dye and Dual Laser Photodynamic Therapy on Oral Biofilms of Enterococcus faecalis, Streptococcus mutans, and Prevotella intermedia: An In Vitro Study.

Aim: To assess and compare the antibacterial efficacy of methylene blue (MB) and red laser (660 nm) antimicrobial photodynamic therapy (aPDT), indocyanine green (ICG) and infrared laser (810 nm) aPDT, and dual-dye (MB and ICG) and dual light (red and infrared) aPDT on oral biofilms of Enterococcus faecalis (E. faecalis), Prevotella intermedia (P. intermedia), and Streptococcus mutans (S. mutans). Materials and methods: Biofilms of E. faecalis, S. mutans, and P. intermedia were grown at 36°C and 5% CO2 for 7 days in a 96-well plate in a brain heart infusion (BHI) growth medium. Before aPDT, a total of 27 inoculums were collected from culture wells and grown on culture plates to assess baseline colony forming units (CFU). The microbial wells were treated with MBaPDT (group I), ICGaPDT (group II), and MBICGaPDT (group III). Post-aPDT, inoculums were collected from wells to be cultured to assess CFU. One-way analysis of variance (ANOVA) and student paired t-tests were used for statistical analysis. The significance level was fixed at p ≤ 0.05. Results: Methylene blue antimicrobial photodynamic therapy (MBaPDT) caused a significant reduction in E. faecalis counts compared to other groups (f = 11.15, p = 0.01). aPDT on S. mutans resulted in a significant (p = 0.04) reduction of bacterial counts in the ICGaPDT group. aPDT on P. intermedia resulted in a significant reduction in bacterial counts (p ≤ 0.05) in MBaPDT and ICGaPDT groups. Conclusion: Dual-dye and dual light aPDT showed an antibacterial effect against E. faecalis. It was ineffective against S. mutans and P. intermedia. Clinical significance: Dual-dye aPDT may effectively reduce E. faecalis counts in infected root canals and improve the outcomes of root canal treatment. How to cite this article: Yavagal C, Yavagal PC, Marwah N, et al. Antibacterial Efficacy of Dual-dye and Dual Laser Photodynamic Therapy on Oral Biofilms of Enterococcus faecalis, Streptococcus mutans, and Prevotella intermedia: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(S-2):S128-S132.

Case report: isolated prevotella intermedia causing intracranial infection detected using metagenomic next generation sequencing.

BACKGROUND: Isolated Prevotella intermedia, a rare gram-negative, rod-shaped, anaerobic bacterium, is rarely detected in clinical practice. It has been associated with infections of the oral cavity and female genital tract, but has never been detected in cerebrospinal fluid (CSF) of patients in China. Accurate detection of causative pathogens is still an arduous task owing to the difficult conditions of anaerobic bacterial culture. Isolated Prevotella intermedia can be detected by metagenomic next generation sequencing (mNGS) of the CSF. Correct diagnosis and antibiotic treatment can help patients avoid life-threatening events. CASE PRESENTATION: Herein, we describe the case of a 64-year-old Chinese woman who presented with typical features of meningoencephalitis. Routine CSF culture failed to identify the causative pathogen. Isolated Prevotella intermedia was detected by mNGS, and the patient was treated with antibacterial agents including ceftriaxone, vancomycin, moxifloxacin, meropenem, metronidazole, and linezolid. The patient underwent surgical treatment for abscess of left frontal parietal lobe, which was observed on magnetic resonance imaging (MRI) and was suspected to be caused by Prevotella intermedia. It was further confirmed that it was a secondary infection from the oral cavity, and the possible etiology might have been dental surgery. Treatment was rendered to the patient based on metagenomic test result, and her condition improved after two months. CONCLUSIONS: This case highlights the role of mNGS in accurate diagnosis of patients with central nervous system infection. In particular, mNGS can be used to identify rare pathogens and confirm the diagnosis in patients with unknown etiology.

Fusobacterium nucleatum and Prevotella in women with periodontitis and preterm birth

Background: Studies try to explain the hypothesis that maternal periodontitis may be associated with preterm birth. Material and methods: This is a case-control study with 120, 40 cases (gestational age <37 weeks) and 80 controls (gestational age ≥37 weeks), that were submitted to the clinical periodontal examination and subgingival biofilm collection. Bacterial DNA of subgingival biofilm was performed and processed by qPCR. Results: Periodontitis was statistically significant in the Case group (35%) when compared to the Control group (11.2%) and Gingival Bleeding Index (GBI), sites with PS ≥ 4mm and sites with CAL ≥ 5mm were statistically higher in the Case group (p < 0.05). The proportions of Pi (p = 0.026) and Fn (p = 0.041) of subgingival biofilm were higher in the Case group. A greater number of sites with PS ≥ 4mm (r = -0.202; p = 0.026) and CAL ≥ 5mm (r = -0.322; p < 0.001) were correlated to lower gestational age. Conclusions: Periodontitis, preterm delivery, and/or low birth weight may have a possible relationship based on clinical parameters and the ratio of Pi and Fn at periodontal sites. (AU)

Evolutionary and Pan-genome Analysis of Three Important Black-pigmented Periodontal Pathogens.

OBJECTIVE: To analyse the pan-genome of three black-pigmented periodontal pathogens: Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens. METHODS: Pan-genome analyses of 66, 33 and 5 publicly available whole-genome sequences of P. gingivalis, P. intermedia and P. nigrescens, respectively, were performed using Pan-genome Analysis Pipeline software (version 1.2.1; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, PR China). Phylogenetic trees were constructed based on the entire pan-genome and single nucleotide polymorphisms within the core genome. The distribution and abundance of virulence genes in the core and dispensable genomes were also compared in the three species. RESULTS: All three species possess an open pan-genome. The core genome of P. gingivalis, P. intermedia and P. nigrescens included 1001, 1514 and 1745 orthologous groups, respectively, which were mainly related to basic cellular functions such as metabolism. The dispensable genome of P. gingivalis, P. intermedia and P. nigrescens was composed of 2814, 2689 and 906 orthologous groups, respectively, and it was enriched in genes involved in pathogenicity or with unknown functions. Phylogenetic trees presented a clear separation of P. gingivalis, P. intermedia and P. nigrescens, verifying the reclassification of the black-pigmented species. Furthermore, the three species shared almost the same virulence factors involved in adhesion, proteolysis and evasion of host defences. Some of these virulence genes were conserved across species whereas others belonged to the dispensable genome, which might be acquired through horizontal gene transfer. CONCLUSION: This study highlighted the usefulness of pan-genome analysis to infer evolutionary cues for black-pigmented species, indicating their homology and phylogenomic diversity.

Simultaneous detection and evaluation of Prevotella intermedia, Prevotella nigrescens, Prevotella loescheii, and Prevotella melaninogenica in subgingival plaque samples of chronic periodontitis and healthy individuals through multiplex polymerase chain reaction.

Background: Prevotella is a Gram-negative anaerobic bacilli. The phenotypic characteristics of the various species of Prevotella are similar, which often makes it difficult in routine differentiation and identification of all the species. Aim: The purpose of the study was to detect and compare presence of Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica, and Prevotella loescheii in subgingival plaque samples of chronic periodontitis and healthy individuals. Materials and Methods: Two hundred and thirty-six subjects were considered consisting of chronic periodontitis (128) and healthy (108) individuals. Subgingival plaque sample was collected in reduced transport fluid and analyzed. DNA extraction and polymerase chain reaction (PCR) were performed for genus Prevotella followed by positive samples were considered for the detection of selected species through multiplex PCR using specific primers. Results: Out of 236 samples, 94.1% were positive for genus Prevotella. Out of 222 cases P. nigrescens showed the highest number of cases positive (59.5%) followed by P. melaninogenica (57.2%), P. intermedia (55.4%), and P. loescheii (40.1%). Species were analyzed individually between chronic periodontitis and healthy, P. intermedia, P. nigrescens, and P. loescheii showed greater positivity in healthy compared to chronic periodontitis. Positivity for P. melaninogenica was high in chronic periodontitis compared to healthy. Conclusion: The number of positive cases for species, when correlated with clinical parameters showed an increase in mean score for all clinical parameters assessed, suggesting the presence of variation in the prevalence of Prevotella species and geographic variation do exist in oral microflora. Findings suggest that they can be normal commensals and opportunistic.

Comparative Evaluation of the Inhibitory Effect of Lactobacillus rhamnosus on Halitosis-Causing Bacteria: An Invitro Microbiological Study.

AIM:  To determine the effectiveness of Lactobacillus rhamnosus in inhibiting halitosis-causing bacteria relative to other possible inhibitors, such as mouthwashes. MATERIALS AND METHODS:  This in vitro study was done using a diffusion test with three groups with 11 samples in each group: group A, Porphyromonas gingivalis; group B, Tannerella forsythia; and group C, Prevotella intermedia. At 24, 48, and 72 hours, the inhibitory effect of L. rhamnosus was tested. RESULTS: A statistically significant difference was seen for halo formation in group A, where all 11 samples showed an inhibitory effect after 72 hours. After 48 hours, seven of the 11 samples in group B and nine of the 11 samples in group C showed inhibitory effects. CONCLUSION:  The study found that L. rhamnosus had an inhibitory effect on halitosis-causing bacteria like P. gingivalis after 72 hours, which was statistically significant. The same was true for T. forsythia and P. intermedia after 48 hours. This means that L. rhamnosus has an inhibitory effect on halitosis-causing bacteria like P. gingivalis.

Iron Deficiency Modulates Metabolic Landscape of Bacteroidetes Promoting Its Resilience during Inflammation.

Bacteria have to persist under low iron conditions in order to adapt to the nutritional immunity of a host. Since the knowledge of iron stimulon of Bacteroidetes is sparse, we examined oral (Porphyromonas gingivalis and Prevotella intermedia) and gut (Bacteroides thataiotaomicron) representatives for their ability to adapt to iron deplete and iron replete conditions. Our transcriptomics and comparative genomics analysis show that many iron-regulated mechanisms are conserved within the phylum. They include genes upregulated in low iron, as follows: fldA (flavodoxin), hmu (hemin uptake operon), and loci encoding ABC transporters. Downregulated genes were frd (ferredoxin), rbr (rubrerythrin), sdh (succinate dehydrogenase/fumarate reductase), vor (oxoglutarate oxidoreductase/dehydrogenase), and pfor (pyruvate:ferredoxin/flavodoxin oxidoreductase). Some genus-specific mechanisms, such as the sus of B. thetaiotaomicron coding for carbohydrate metabolism and the xusABC coding for xenosiderophore utilization were also identified. While all bacteria tested in our study had the nrfAH operon coding for nitrite reduction and were able to reduce nitrite levels present in culture media, the expression of the operon was iron dependent only in B. thetaiotaomicron. It is noteworthy that we identified a significant overlap between regulated genes found in our study and the B. thetaiotaomicron colitis study (W. Zhu, M. G. Winter, L. Spiga, E. R. Hughes et al., Cell Host Microbe 27:376-388, 2020, http://dx.doi.org/10.1016/j.chom.2020.01.010). Many of those commonly regulated genes were also iron regulated in the oral bacterial genera. Overall, this work points to iron being the master regulator enabling bacterial persistence in the host and paves the way for a more generalized investigation of the molecular mechanisms of iron homeostasis in Bacteroidetes. IMPORTANCE Bacteroidetes are an important group of anaerobic bacteria abundant both in the oral and gut microbiomes. Although iron is a required nutrient for most living organisms, the molecular mechanisms of adaptation to the changing levels of iron are not well known in this group of bacteria. We defined the iron stimulon of Bacteroidetes by examination of the transcriptomic response of Porphyromonas gingivalis and Prevotella intermedia (both belong to the oral microbiome) and Bacteroidetes thetaiotaomicron (belongs to the gut microbiome). Our results indicate that many of the iron-regulated operons are shared among the three genera. Furthermore, using bioinformatics analysis, we identified a significant overlap between our in vitro studies and transcriptomic data derived from a colitis study, thus underscoring the biological significance of our work. Defining the iron-dependent stimulon of Bacteroidetes can help to identify the molecular mechanisms of iron-dependent regulation as well as better understand the persistence of the anaerobes in the human host.

Hemophore-like proteins produced by periodontopathogens are recognized by the host immune system and react differentially with IgG antibodies.

Aims: Hemophore-like proteins sequester heme from host hemoproteins. We aimed to determine whether the host immune system can recognize not only Porphyromonas gingivalis HmuY but also its homologs expressed by other periodontopathogens, and how periodontitis influences the production of respective antibodies. Methods: The reactivity of total bacterial antigens and purified proteins with serum IgG antibodies of 18 individuals with periodontitis and 17 individuals without periodontitis was examined by enzyme-linked immunosorbent assay (ELISA). To compare IgG reactivity between groups with and without periodontitis and within the various dilutions of sera, statistical analysis was performed using the Mann-Whitney U-test and two-way ANOVA test with the post-hoc Bonferroni test. Results: Individuals with periodontitis produced IgG antibodies reacting more strongly not only with total P. gingivalis antigens (P = 0.0002; 1:400) and P. gingivalis HmuY (P = 0.0016; 1:100) but also with Prevotella intermedia PinA (P = 0.0059; 1:100), and with low efficiency with P. intermedia PinO (P = 0.0021; 1:100). No increase in the reactivity of IgG antibodies with Tannerella forsythia Tfo and P. gingivalis HusA was found in individuals with periodontitis. Conclusions: Although hemophore-like proteins are structurally related, they are differentially recognized by the host immune system. Our findings point to specific antigens, mainly P. gingivalis HmuY and P. intermedia PinA, whose immunoreactivity could be further investigated to develop markers of periodontitis.

Determination and comparison of antimicrobial activity of aqueous and ethanolic extracts of Amorphophallus paeoniifolius on periodontal pathogens: An in vitro study.

Background: People globally are turning to herbal products to reconnect with nature. Cost efficacy and minimal side effects are the reasons for this changeover. This study assessed the effect of Amorphophallus paeoniifolius as an antimicrobial agent against Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum. Aim: To determine and compare the antimicrobial activity of aqueous and ethanolic extracts of A. paeoniifolius on periodontal pathogens. Materials and Methods: Aqueous and ethanolic extracts of A. paeoniifolius were tested against the standard strains of the selected bacteria. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were used. These tests assessed the lowest concentrations of test agent, either by showing a lack of turbidity or by no or few bacterial growth colonies, respectively. In this study, tetracycline hydrochloride was used as the control group. Results: Aqueous and ethanolic extracts of A. paeoniifolius showed antibacterial activity at various concentrations against the selected organisms. While assessing the MBC, the aqueous and ethanolic extracts of A. paeoniifolius and tetracycline hydrochloride exhibited bactericidal activity against F. nucleatum at all concentrations. The ethanolic extract of Amorphophallus paeoniifolius and tetracycline hydrochloride showed bactericidal action, whereas the aqueous extract exhibited bacteriostatic action against P. gingivalis. The aqueous and ethanolic extracts of A. paeoniifolius showed bacteriostatic action, whereas tetracycline hydrochloride showed bactericidal action against P. intermedia. Conclusion: Both aqueous and ethanolic extracts of A. paeoniifolius showed antibacterial activity against standard strains of P. gingivalis, P. intermedia, and F. nucleatum. The ethanolic extract showed a significant antibacterial effect against the selected microorganisms when compared to the aqueous extract of A. paeoniifolius.

Serum antibodies to periodontal pathogens prior to rheumatoid arthritis diagnosis: A case-control study.

OBJECTIVES: 1) To quantify the association between anti-Porphyromonas gingivalis serum antibody concentrations and the risk of developing rheumatoid arthritis (RA), and 2) to quantify the associations among RA cases between anti-P. gingivalis serum antibody concentrations and RA-specific autoantibodies. Additional anti-bacterial antibodies evaluated included anti-Fusobacterium nucleatum and anti-Prevotella intermedia. METHODS: Serum samples were acquired pre- and post- RA diagnosis from the U.S. Department of Defense Serum Repository (n = 214 cases, 210 matched controls). Using separate mixed-models, the timing of elevations of anti-P. gingivalis, anti-P. intermedia, and anti-F. nucleatum antibody concentrations relative to RA diagnosis were compared in RA cases versus controls. Associations were determined between serum anti-CCP2, ACPA fine specificities (vimentin, histone, and alpha-enolase), and IgA, IgG, and IgM RF in pre-RA diagnosis samples and anti-bacterial antibodies using mixed-effects linear regression models. RESULTS: No compelling evidence of case-control divergence in serum anti-P. gingivalis, anti-F. nucleatum, and anti-P. intermedia was observed. Among RA cases, including all pre-diagnosis serum samples, anti-P. intermedia was significantly positively associated with anti-CCP2, ACPA fine specificities targeting vimentin, histone, alpha-enolase, and IgA RF (p<0.001), IgG RF (p = 0.049), and IgM RF (p = 0.004), while anti-P. gingivalis and anti-F. nucleatum were not. CONCLUSIONS: No longitudinal elevations of anti-bacterial serum antibody concentrations were observed in RA patients prior to RA diagnosis compared to controls. However, anti-P. intermedia displayed significant associations with RA autoantibody concentrations prior to RA diagnosis, suggesting a potential role of this organism in progression towards clinically-detectable RA.

Antibacterial Efficacy of Matricaria recutita Essential Oil against Porphyromonas gingivalis and Prevotella intermedia: In Vitro Study.

AIM: To evaluate in vitro the antibacterial efficacy of Matricaria recutita (chamomile) essential oil at 50 and 75% against Porphyromonas gingivalis ATCC 33277 and Prevotella intermedia ATCC 25611 at 24 and 48 hours. MATERIAL AND METHODS: The sample consisted of 80 discs and Mueller-Hinton Agar, the medium chosen for the culture. To determine the bacterial sensitivity, discs were placed in each Petri dish with concentrations of essential oil at 50 and 75%, distilled water and 0.12% chlorhexidine. Subsequently, the inhibition halos were measured in millimeters at 24 and 48 hours after culture, with the Kirby-Bauer disk diffusion method. RESULTS: In groups treated with Porphyromonas gingivalis, measurements at 24 and 48 hours yielded 22.14 ± 2.61 and 22.63 ± 2.67 mm for 0.12% chlorhexidine, 18.90 ± 0.41 and 19.22 ± 0.54 mm for 75% essential oil, and 15.55 ± 0.45 and 15.77 ± 0.46 mm for 50% essential oil, respectively. No statistically significant differences were observed among the groups (p > 0.05). CONCLUSION: No significant differences were found between the antibacterial efficacy of 0.12% chlorhexidine and 50 and 75% essential oil of Matricaria recutita on Porphyromonas gingivalis and Prevotella intermedia at 24 and 48 hours. CLINICAL SIGNIFICANCE: The study demonstrates that essential oil derived from Matricaria recutita may effectively combat bacteria associated with periodontal disease. This discovery has the potential to impact dental practice by introducing a natural treatment option. Further research is warranted to fully elucidate the clinical significance and potential applications of this finding.

Effectiveness of Diode (810 nm) Laser in Periodontal Parameters and Reduction of Subgingival Bacterial Load in Periodontitis Patients.

AIM: This split-mouth randomized trial (RCT) aimed to assess the effect of diode laser on the clinical parameters in patients with periodontitis, compare the results with scaling and root planing (SRP) alone, and assess the implications of diode laser (DL) on plaque bacteria. MATERIALS AND METHODS: Seventeen periodontitis patients were randomly assigned into two equal groups based on the therapy delivered. Group I (control site) received just SRP at baseline, while group II (test site) received both SRP and DL irradiation. For both groups, the clinical periodontal parameters probing pocket depth (PPD), and clinical attachment level (CAL) were measured at baseline, 30 days, and 90 days. Microbiological amount was also measured at baseline, 30, and 90 days after periodontal treatment. The amounts of Aggregatibacter actinomycetemcomitans (A.a), Prevotella intermedia (Pr. intermedia), and Porphyromonas gingivalis (P. gingivalis) were determined using real-time PCR probing with specific bacterial primers. RESULTS: In both groups, PPD and CAL showed statistically significant reductions at different time intervals (p < 0.05). No significant difference were observed in CAL values after 1 and 3 months in both test and control groups (p > 0.05). The mean values of the concentration of A.a, Pr. intermedia and P. gingivalis were lower in the case group as compared to the control group and the difference was statistically significant after 1 month (*p = 0.001). CLINICAL SIGNIFICANCE: According to this study, non-invasive laser treatment has the potential to improve clinical outcomes by lowering the quantity of A.a, Pr. intermedia and P. gingivalis. CONCLUSION: In both groups, a considerable decrease in the periodontal pathogens A.a, Pr. intermedia and P. gingivalis were discovered; however, the intergroup comparison was insignificant in relation to PD and CAL. The adjunctive treatment with diode laser showed better efficacy in ensuring a better periodontal treatment than SRP alone. How to cite this article: Abdullah LA, Hashim N, Rehman MM, et al. Effectiveness of Diode (810 nm) Laser in Periodontal Parameters and Reduction of Subgingival Bacterial Load in Periodontitis Patients. J Contemp Dent Pract 2023;24(12):1008-1015.

The oral microbiome in young women at different stages of periodontitis: Prevotella dominant in stage III periodontitis.

Objective: Periodontitis progression is related to the dynamic dysbiosis of oral microbiome. We identified the dominant bacteria and the potential pathway in young women with stage-III periodontitis. Materials and methods: Samples of subgingival plaque were collected from 26 young women with periodontitis (20 with stage-I and 6 with stage-III). Using 16S rRNA-sequencing, we determined the variation in oral bacterial communities of the two groups, and identified the dominant bacteria of each group. We used the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to evaluate the signaling pathways related to the difference in oral bacterial composition. The role of the dominant bacteria of stage-III periodontitis was investigated in vivo and in vitro using an endoplasmic reticulum stress inhibitor. Results: Young women with stage-I periodontitis had higher values for the Chao1 Index, Observed Species and Phylogenetic Diversity Whole Tree Index than those for women with stage-III periodontitis. ß-diversity analyses revealed that samples could be divided into different groups according to the periodontitis stage. The most representative biomarkers of stage-III periodontitis in young women were bacteria of the phylum Bacteroidetes, its order, family and genera Bacteroidales, Prevotellaceae and Prevotella. The KEGG database revealed that the change in oral bacterial composition of young women with stage-III periodontitis may be related to protein processing in an endoplasmic reticulum pathway. Salubrinal (an endoplasmic reticulum stress regulator) controlled expression of Runx2, Col1a1, Ocn in mouse bone-marrow mesenchymal cells. Salubrinal administration showed that moderate endoplasmic reticulum stress inhibited alveolar bone loss in periodontitis induced by Prevotella intermedia lipopolysaccharide. Conclusion: Differences between periodontitis stages were noted and bacteria of Prevotella species were abundant in young women with stage-III periodontitis. This phenomenon was related to protein processing in an endoplasmic reticulum pathway.