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Anaerobe Jun 2022The dysbiosis of bacteria and horizontal transfer of antibiotic resistance genes (ARGs) could be highly problematic particularly in the oral environment. Here, we aimed...
OBJECTIVES
The dysbiosis of bacteria and horizontal transfer of antibiotic resistance genes (ARGs) could be highly problematic particularly in the oral environment. Here, we aimed to identify the anaerobic species from patients with periodontitis and to screen the isolates for the β-lactamase resistance genes, bla, cfxA, its variants, and mobA.
METHODS
The 129 samples from periodontal pockets were subjected to anaerobic culture, followed by 16S rRNA gene sequencing, PCR assays for the cfxA, bla, and mobA. The minimum inhibitory concentration (MIC) of amoxicillin, ampicillin, amoxicillin/clavulanate, ampicillin/sulbactam, and cefixime was determined against CfxA producing isolates using MIC Test Strips.
RESULTS
The species with frequency higher than 10% were Lactobacillus spp. (26.3%), Streptococcus spp. (18.8%), Leptotrichia wadei (14%) and Veillonella spp. (11.4%). The bla was not found in any of the isolates whereas cfxA was found in 12.5% of isolates including V. parvula, V. rogosae, Prevotella nigrescens and Campylobacter concisus. Of CfxA variants, CfxA2 (90%) was the most frequent one. Among the CfxA producing isolates, the resistance to ampicillin and amoxicillin was observed only in two isolates of P. nigrescens and V. rogosae.
CONCLUSIONS
This study showed that various anaerobes species may be involved in the development of periodontitis. Of them, Prevotella and Veillonella species were found to commonly carry cfxA even though they are susceptible to beta-lactams and its combination.
Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteria, Anaerobic; Humans; Iran; Microbial Sensitivity Tests; Periodontitis; RNA, Ribosomal, 16S; beta-Lactam Resistance; beta-Lactamases
PubMed: 35026418
DOI: 10.1016/j.anaerobe.2022.102515 -
ACS Applied Bio Materials Mar 2021The beneficial effects of Sr- and Mg-doped hydroxyapatite (HAp) on osteoblast proliferation and bone regeneration have been investigated in the past, and the...
The beneficial effects of Sr- and Mg-doped hydroxyapatite (HAp) on osteoblast proliferation and bone regeneration have been investigated in the past, and the antibacterial ability of Zn ions is well known. However, HAp coatings doped with these three elements via thermal spraying have not yet been investigated. In this study, HAp powder was synthesized at different pH values (4, 6, 8, and 10) and calcined at different temperatures (200, 400, 600, 800, and 1000 °C) to obtain HAp with the highest purity. Subsequently, strontium-, magnesium-, and zinc-doped HAp powders were synthesized at the optimal pH value and calcination temperature. The HAp powder was then coated onto Ti disks using atmospheric plasma spraying (APS) or vapor-induced pore-forming atmospheric plasma spraying (VIPF-APS) techniques at different working currents (350, 400, and 450 A) and spraying distances (10 and 15 cm). X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy equipped with energy-dispersive spectroscopy were used for material characterization to determine the optimal parameters. With these optimal coating parameters, HAp, Zn-HAp, SrMg-HAp, and ZnSrMg-HAp powders were deposited onto the Ti disks using VIPF-APS and named HAp-Ti, Zn-HAp-Ti, SrMg-HAp-Ti, and ZnSrMg-HAp-Ti, respectively. The in vitro bioactivity of these four groups was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and alkaline phosphatase (ALPase) activity assay. Besides, the antibacterial activities against , , and were assessed. The results showed that the purity of HAp synthesized at pH 10 and 800 °C was 98.40%. A porous coating without cracks was obtained at a 10 cm spraying distance and 400 A working current using VIPF-APS. SrMg-HAp-Ti and ZnSrMg-HAp-Ti resulted in higher osteoblast proliferation and ALPase activity than the control. Moreover, both Zn-HAp-Ti and ZnSrMg-HAp-Ti exhibited antibacterial activity against the three bacteria. Therefore, ZnSrMg-HAp has potential as a coating for biomedical materials due to its ability to reduce bacterial infection and enhance osseointegration.
Topics: Anti-Bacterial Agents; Atmosphere; Coated Materials, Biocompatible; Durapatite; Fusobacterium nucleatum; Magnesium; Materials Testing; Microbial Sensitivity Tests; Particle Size; Porosity; Porphyromonas gingivalis; Prevotella nigrescens; Strontium; Surface Properties; Zinc
PubMed: 35014370
DOI: 10.1021/acsabm.0c01535 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Dec 2021To investigate the prevalence of five specific periodontal pathogens in the saliva of edentulous patients and to compare the differences in the saliva of dentulous...
To investigate the prevalence of five specific periodontal pathogens in the saliva of edentulous patients and to compare the differences in the saliva of dentulous individuals with various periodontal conditions. All the subjects were patients who received regular care at the Beijing Hypertension Prevention and Management Institute. Twenty-seven edentulous patients (edentulous group) were included. According to age (age gap≤5 years), gender, smoking status, diabetes status and hypertension status, each edentulous patient was paired with dentulous individuals suffering from various severity of periodontitis in the same cohort. Then, we selected 3 groups of patients (27 in each group) with no or mild periodontitis (mild group), moderate periodontitis (moderate group) and severe periodontitis (severe group). The whole unstimulated saliva was collected before the periodontal examination. Questionnaire survey and periodontal parameters, including plaque index (PLI), probing depth (PD), bleeding index (BI) and clinical attachment loss (CAL), were examined at mesial-buccal and distal-lingual sites of each tooth respectively. DNA was extracted from each sample of the salivary deposition. (Pg), (Tf), (Td), (Cr) and (Pn) were detected by using PCR method based on 16SrRNA. The prevalence and quantity of the pathogens under various severity of periodontitis were compared. One or more periodontal pathogens could be detected from the 78% (21/27) of the salivary samples in edentulous group. Thereinto, the prevalences of the five periodontal pathogens were ranked as (from high to low): Cr [56% (15/27)], Tf [44% (12/27)], Pn [26% (7/27)], Pg [22% (6/27)] and Td [11% (3/27)]. All five pathogens' prevalences and Pg, Tf, Td and Pn's quantities showed statistical differences among the four groups. The numbers of detected bacterial species in the mild, moderate and severe groups were significantly higher than that in the edentulous group (0.01). Furthermore, the prevalences of the red complex in three dentulous groups [96% (26/27) in each group] were significantly higher than the edentulous group [48% (13/27)] (0.05). The proportions of the red complex among all five pathogens (83%) in moderate and severe groups were significantly higher than that in the edentulous group (37%) (0.01). All five periodontal pathogens could be detected in most of the saliva samples from edentulous individuals. Nevertheless, the prevalence and quantity were lower than dentulous individuals.
Topics: Beijing; Child, Preschool; Cross-Sectional Studies; Humans; Saliva
PubMed: 34915658
DOI: 10.3760/cma.j.cn112144-20210305-00102 -
Scientific Reports Aug 2021We have measured the volatile fingerprints of four pathogenic oral bacteria connected to periodontal disease and dental abscess: Porphyromonas gingivalis (three separate...
We have measured the volatile fingerprints of four pathogenic oral bacteria connected to periodontal disease and dental abscess: Porphyromonas gingivalis (three separate strains), Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia. Volatile fingerprints were measured in vitro from the headspace gas of the bacteria cultured on agar. Concrete identification of new and previously reported bacterial volatiles were performed by a combination of solid phase microextraction (SPME) and offline gas chromatography-mass spectrometry (GC-MS). We also studied the effect of the reduced electric field strength (E/N) on the fragmentation patterns of bacterial volatiles in online proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). We aimed to discover possible new biomarkers for the studied oral bacteria, as well as to validate the combination of GC-MS and PTR-MS for volatile analysis. Some of the most promising compounds produced include: 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), indole, and a cascade of sulphur compounds, such as methanethiol, dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS). We also found that several compounds, especially alcohols, aldehydes and esters, fragment significantly with the PTR-MS method, when high E/N values are used. We conclude that the studied oral bacteria can be separated by their volatile fingerprints in vitro, which could have importance in clinical and laboratory environments. In addition, using softer ionization conditions can improve the performance of the PTR-MS method in the volatile analysis of certain compounds.
Topics: Bacteria; Biomarkers; Gas Chromatography-Mass Spectrometry; Mouth; Protons; Volatile Organic Compounds
PubMed: 34413397
DOI: 10.1038/s41598-021-96287-7 -
The Journal of Biological Chemistry Sep 2021Modular protein assembly has been widely reported as a mechanism for constructing allosteric machinery. Recently, a distinctive allosteric system has been identified in...
Modular protein assembly has been widely reported as a mechanism for constructing allosteric machinery. Recently, a distinctive allosteric system has been identified in a bienzyme assembly comprising a 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS) and chorismate mutase (CM). These enzymes catalyze the first and branch point reactions of aromatic amino acid biosynthesis in the bacterium Prevotella nigrescens (PniDAH7PS), respectively. The interactions between these two distinct catalytic domains support functional interreliance within this bifunctional enzyme. The binding of prephenate, the product of CM-catalyzed reaction, to the CM domain is associated with a striking rearrangement of overall protein conformation that alters the interdomain interactions and allosterically inhibits the DAH7PS activity. Here, we have further investigated the complex allosteric communication demonstrated by this bifunctional enzyme. We observed allosteric activation of CM activity in the presence of all DAH7PS substrates. Using small-angle X-ray scattering (SAXS) experiments, we show that changes in overall protein conformations and dynamics are associated with the presence of different DAH7PS substrates and the allosteric inhibitor prephenate. Furthermore, we have identified an extended interhelix loop located in CM domain, loop, as a crucial segment for the interdomain structural and catalytic communications. Our results suggest that the dual-function enzyme PniDAH7PS contains a reciprocal allosteric system between the two enzymatic moieties as a result of this bidirectional interdomain communication. This arrangement allows for a complex feedback and feedforward system for control of pathway flux by connecting the initiation and branch point of aromatic amino acid biosynthesis.
Topics: 3-Deoxy-7-Phosphoheptulonate Synthase; Allosteric Regulation; Amino Acid Sequence; Amino Acids, Aromatic; Bacterial Proteins; Biosynthetic Pathways; Enzyme Inhibitors; Prevotella nigrescens; Protein Domains; Scattering, Small Angle; Sequence Alignment
PubMed: 34343567
DOI: 10.1016/j.jbc.2021.101038 -
Scientific Reports Jul 2021A growing body of evidence supports an important role for alterations in the brain-gut-microbiome axis in the aetiology of depression and other psychiatric disorders....
A growing body of evidence supports an important role for alterations in the brain-gut-microbiome axis in the aetiology of depression and other psychiatric disorders. The potential role of the oral microbiome in mental health has received little attention, even though it is one of the most diverse microbiomes in the body and oral dysbiosis has been linked to systemic diseases with an underlying inflammatory aetiology. This study examines the structure and composition of the salivary microbiome for the first time in young adults who met the DSM-IV criteria for depression (n = 40) and matched controls (n = 43) using 16S rRNA gene-based next generation sequencing. Subtle but significant differences in alpha and beta diversity of the salivary microbiome were observed, with clear separation of depressed and healthy control cohorts into distinct clusters. A total of 21 bacterial taxa were found to be differentially abundant in the depressed cohort, including increased Neisseria spp. and Prevotella nigrescens, while 19 taxa had a decreased abundance. In this preliminary study we have shown that the composition of the oral microbiome is associated with depression in young adults. Further studies are now warranted, particuarly investigations into whether such shifts play any role in the underling aetiology of depression.
Topics: Adolescent; Adult; Age Factors; Bacteria; Biodiversity; Case-Control Studies; Depression; Female; Host Microbial Interactions; Humans; Male; Metagenome; Metagenomics; Microbiota; Mouth; Saliva; Young Adult
PubMed: 34294835
DOI: 10.1038/s41598-021-94498-6 -
Journal of Dental Research Sep 2021Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque...
Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM-20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, , , , and by 3 to 5-log ( < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera , , , , and , while and dominated the 5% DMAHDM-20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations' life span.
Topics: Aggregatibacter actinomycetemcomitans; Anti-Bacterial Agents; Biofilms; Methacrylates; Nanocomposites; RNA, Ribosomal, 16S
PubMed: 34167373
DOI: 10.1177/00220345211018189 -
Journal of Cystic Fibrosis : Official... Jul 2021In Cystic Fibrosis (CF) airways, the dehydrated, thick mucus promotes the establishment of persistent polymicrobial infections and drives chronic airways inflammation....
BACKGROUND
In Cystic Fibrosis (CF) airways, the dehydrated, thick mucus promotes the establishment of persistent polymicrobial infections and drives chronic airways inflammation. This also predisposes the airways to further infections, the vicious, self-perpetuating cycle causing lung damage and progressive lung function decline. The airways are a poly-microbial environment, containing both aerobic and anaerobic bacterial species. Pseudomonas aeruginosa (P. aeruginosa) infections contribute to the excessive inflammatory response in CF, but the role of anaerobic Prevotella spp., frequently found in CF airways, is not known.
MATERIALS
We assessed innate immune signalling in CF airway epithelial cells in response to clinical strains of P. histicola, P. nigresens and P. aeruginosa. CFBE41o- cells were infected with P. aeruginosa (MOI 100, 2h) followed by infection with P. histicola or P. nigrescens (MOI 100, 2h). Cells were incubated under anaerobic conditions for the duration of the experiments.
RESULTS
Our study shows that P. histicola and P. nigresens can reduce the growth of P. aeruginosa and dampen the inflammatory response in airway epithelial cells. We specifically illustrate that the presence of the investigated Prevotella spp. reduces Toll-like-receptor (TLR)-4, MAPK, NF-κB(p65) signalling and cytokine release (Interleukin (IL)-6, IL-8) in mixed infections.
CONCLUSION
Our work, for the first time, strongly indicates a relationship between P. aeruginosa and anaerobic Prevotella spp.. The observed modified NF-κB and MAPK signalling indicates some mechanisms underlying this interaction that could offer a novel therapeutic approach to combat chronic P. aeruginosa infection in people with CF.
Topics: Bronchi; Cells, Cultured; Cystic Fibrosis; Epithelial Cells; Humans; Inflammation; Prevotella; Pseudomonas Infections; Pseudomonas aeruginosa; Respiratory Mucosa
PubMed: 34112603
DOI: 10.1016/j.jcf.2021.04.012 -
Journal of Clinical Medicine Feb 2021This study aimed to evaluate the feasibility of diagnosing periodontitis via the identification of 18 bacterial species in mouth-rinse samples. Patients (n = 110) who...
This study aimed to evaluate the feasibility of diagnosing periodontitis via the identification of 18 bacterial species in mouth-rinse samples. Patients (n = 110) who underwent dental examinations in the Department of Periodontology at the Veterans Health Service Medical Center between 2018 and 2019 were included. They were divided into healthy and periodontitis groups. The overall number of bacteria, and those of 18 specific bacteria, were determined via real-time polymerase chain reaction in 92 mouth-rinse samples. Differences between groups were evaluated through logistic regression after adjusting for sex, age, and smoking history. There was a significant difference in the prevalence (healthy vs. periodontitis group) of (2.9% vs. 13.5%), (42.9% vs. 69.2%), and (80% vs. 2.7%). Levels of , , and were significantly associated with severe periodontitis. We demonstrated the feasibility of detecting periopathogenic bacteria in mouth-rinse samples obtained from patients with periodontitis. As we did not comprehensively assess all periopathogenic bacteria, further studies are required to assess the potential of oral-rinsing solutions to indicate oral infection risk and the need to improve oral hygiene, and to serve as a complementary method for periodontal disease diagnosis.
PubMed: 33671765
DOI: 10.3390/jcm10040891 -
International Journal of Medical... 2021is an oral pathogen that is frequently observed in the subgingival plaque of periodontitis patients. Interleukin-1β (IL-1β) is known to be involved in the...
is an oral pathogen that is frequently observed in the subgingival plaque of periodontitis patients. Interleukin-1β (IL-1β) is known to be involved in the immunopathology of periodontal diseases and has been implicated in the destruction of bone. In this study, we investigated the mechanism of IL-1β production by in murine bone marrow-derived dendritic cells (BMDCs). Our results showed that a host receptor, Toll-like receptor 2 (TLR2), but not TLR4 is required for pro-IL-1β induction and nucleotide-binding oligomerization domain like receptor pyrin domain containing 3 (NLRP3) priming in BMDCs in response to and activation of the NLRP3 inflammasome is necessary for processing of pro-IL-1β into mature IL-1β. In addition, an inhibitor assay revealed that production of reactive oxygen species, P2XR activity, and release of cathepsin B are involved in IL-1β production in BMDCs in response to
Topics: Animals; Cathepsin B; Cells, Cultured; Dendritic Cells; Disease Models, Animal; Gram-Negative Bacterial Infections; Humans; Inflammasomes; Interleukin-1beta; Mice; NLR Family, Pyrin Domain-Containing 3 Protein; Periodontitis; Prevotella nigrescens; Primary Cell Culture; Reactive Oxygen Species; Receptors, Purinergic P2X7; Signal Transduction; Toll-Like Receptor 2
PubMed: 33390812
DOI: 10.7150/ijms.47197