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Oral Microbiology and Immunology Oct 1994Most likely, young children acquire their oral microflora by frequent transfer of bacteria between family members. The possible transmission of obligately anaerobic...
Most likely, young children acquire their oral microflora by frequent transfer of bacteria between family members. The possible transmission of obligately anaerobic Prevotella melaninogenica recovered from 11 mother-child pairs was examined by ribotyping. One to 18 isolates (mean 13) per child from different oral sampling sites and 4 to 17 (mean 10) isolates per mother from stimulated salivary samples, collected on 2 occasions, were analyzed. On sampling, the mean ages of the children were 4 months and 32 months, respectively. Restriction endonucleases KpnI and ClaI were chosen for the digestion of chromosomal DNA. DNA fragments were electrophoretically separated, blotted onto a nylon membrane and hybridized with rRNA operon of Escherichia coli. DNA-DNA hybrids were detected immunologically. Extensive genetic heterogeneity, 101 distinct ribotypes, was observed among 248 P. melaninogenica isolates studied. Both mothers and children harbored several (up to 7) ribotypes which, apart from 3 ribotypes, were distinguishable in unrelated subjects. Several P. melaninogenica ribotypes were detected on both sampling occasions over 2 years apart. Identical ribotypes were found in 6 of the 11 mother-child pairs, 1 to 2 similar ribotypes per pair. This suggests the transmission of P. melaninogenica between the mother and her child, probably via maternal saliva. However, the unique ribotypes found in these children also indicate that other sources besides the mother influence the oral colonization of young children.
Topics: Adult; Blotting, Southern; Child, Preschool; DNA, Bacterial; DNA, Ribosomal; Female; Genetic Heterogeneity; Humans; Infant; Infectious Disease Transmission, Vertical; Mothers; Periodontal Diseases; Prevotella melaninogenica; Saliva
PubMed: 7808775
DOI: 10.1111/j.1399-302x.1994.tb00077.x -
Nature Communications Jun 2022This study investigates how specific members of the lung microbiome influence the early immune response to infection. Prevotella species are a major component of the...
This study investigates how specific members of the lung microbiome influence the early immune response to infection. Prevotella species are a major component of the endogenous airway microbiota. Increased abundance of Prevotella melaninogenica correlates with reduced infection with the bacterial pathogen Streptococcus pneumoniae, indicating a potentially beneficial role. Here, we show that P. melaninogenica enhances protection against S. pneumoniae, resulting in rapid pathogen clearance from the lung and improved survival in a mouse lung co-infection model. This response requires recognition of P. melaninogenica lipoproteins by toll-like receptor (TLR)2, the induction of TNFα, and neutrophils, as the loss of any of these factors abrogates Prevotella-induced protection. Improved clearance of S. pneumoniae is associated with increased serine protease-mediated killing by lung neutrophils and restraint of P. melaninogenica-induced inflammation by IL-10 in co-infected mice. Together, these findings highlight innate immune priming by airway Prevotella as an important protective feature in the respiratory tract.
Topics: Animals; Disease Models, Animal; Lung; Mice; Mice, Inbred C57BL; Neutrophil Activation; Neutrophils; Prevotella; Streptococcus pneumoniae; Toll-Like Receptor 2
PubMed: 35680890
DOI: 10.1038/s41467-022-31074-0 -
Anaerobe Oct 2005Although Prevotella melaninogenica belongs to the commensal oral microbiota, some strains possess putative virulence factors. For example, we have previously described...
Although Prevotella melaninogenica belongs to the commensal oral microbiota, some strains possess putative virulence factors. For example, we have previously described fimbriated, hemagglutinating strains of P. melaninogenica, isolated from patients with periodontal disease. The aim of this investigation was to compare some chemical and physical properties of hemagglutination (HA) of P. melaninogenica with those of other pigmented gram-negative anaerobes. HA of 13 P. melaninogenica strains proved to be considerably weaker than that of the major periodontal pathogen, Porphyromonas gingivalis. Vigorous shaking reduced HA of shaken cells but the shaken supernatant had the same hemagglutinating activity as non-shaken cells. The hemagglutinating agent on P. melaninogenica seemed to be a protein, which can be separated from the cell and binds to lactose-, galactose-, and raffinose-containing carbohydrates on the erythrocytes. Adherence to epithelial cells did not differ significantly between the hemagglutinating and non-hemagglutinating strains of P. melaninogenica. Although P. melaninogenica is able to agglutinate erythrocytes, this potential virulence factor is of a considerably lower magnitude than that of major periodontal pathogens.
PubMed: 16701585
DOI: 10.1016/j.anaerobe.2005.02.004 -
Molecular Oral Microbiology Apr 2024Oral lichen planus (OLP) is one of the most common oral mucosal diseases, exhibiting a higher prevalence in women than men, but its pathogenesis is still unclear....
BACKGROUND
Oral lichen planus (OLP) is one of the most common oral mucosal diseases, exhibiting a higher prevalence in women than men, but its pathogenesis is still unclear. Current research suggests that microbial dysbiosis may play an important role in the pathogenesis of OLP. Our previous research has found that the increase of Prevotella melaninogenica and decrease of Streptococcus salivarius have been identified as a potential pathogenic factor in OLP. Consequently, the objective of this study is to examine whether S. salivarius can counteract the detrimental effects of P. melaninogenica on the integrity of the epithelial barrier function.
MATERIALS AND METHODS
Epithelial barrier disruption was induced by P. melaninogenica in human keratinocytes (HaCaT cells). HaCaT cells were pretreated with S. salivarius(MOI = 20) or cell-free supernatant for 3 h, followed by treatment with P. melaninogenica (MOI = 5) for 3 h. The epithelial barrier integrity of HaCaT cells was detected by FD4 permeability. The mRNA level of tight junction protein was detected by quantitative real-time polymerase chain reaction (PCR). Immunofluorescence and Western Blot were used to detect the protein expression of zonula occludin-1 (ZO-1). The serial dilution-spotting assay was applied to monitor the viability of P. melaninogenica at the end of 8 and 24 h incubation.
RESULTS
Challenge by P. melaninogenica decreased the levels of tight junction proteins, including occludin, ZO-1, and claudin in HaCaT cells. S. salivarius or its cell-free supernatant inhibited the down-regulation of ZO-1 mRNA and protein expression levels induced by P. melaninogenica and thus improved the epithelial barrier function. The inhibitory effect of the cell-free supernatant of S. salivarius on the growth of P. melaninogenica is associated with metabolic acid production rather than with bacteriocins and hydrogen peroxide.
CONCLUSIONS
These results suggest that live S. salivarius or its cell-free supernatant significantly ameliorated the disruption of epithelial tight junctions induced by P. melaninogenica, likely through the inhibition of P. melaninogenica growth mediated by metabolic acid production.
PubMed: 38686511
DOI: 10.1111/omi.12464 -
Free Radical Biology & Medicine May 2008Strict anaerobes are highly sensitive to oxygen, but the mutagenicity of oxygen in strict anaerobes has not been well understood. Prevotella melaninogenica, a strict...
Strict anaerobes are highly sensitive to oxygen, but the mutagenicity of oxygen in strict anaerobes has not been well understood. Prevotella melaninogenica, a strict anaerobe, is susceptible to oxygen and shows an increase in oxidative DNA damage upon exposure to oxygen. In this study, we have investigated the mutagenicity of oxygen and the types of mutations induced by oxygen. Exposure to oxygen decreased cell survival and increased the levels of 8-oxo-deoxyguanosine (8-oxodG). The frequency of rifampicin-resistant mutants was markedly increased after exposure to oxygen. After sequencing a 254-bp fragment of the rpoB gene, which encodes the beta subunit of bacterial RNA polymerase, a target molecule of rifampicin, we found that most mutants induced by oxygen had GC to TA transversions, a signature of 8-oxodG. In addition, all detected single-nucleotide changes would lead to amino acid changes that confer rifampicin resistance. These results indicate that oxygen is mutagenic in a strict anaerobe, P. melaninogenica, and its mutagenic characteristics could be analyzed with this experimental system.
Topics: 8-Hydroxy-2'-Deoxyguanosine; Amino Acid Sequence; Antibiotics, Antitubercular; Bacterial Proteins; DNA Damage; Deoxyguanosine; Molecular Sequence Data; Mutation; Oxygen; Prevotella melaninogenica; Rifampin
PubMed: 18343236
DOI: 10.1016/j.freeradbiomed.2008.02.003 -
British Medical Journal (Clinical... Mar 1982To assess the causative role of non-sporing anaerobes in cass of erosive balanoposthitis, anaerobic culture was performed on purulent discharges from 104 patients with...
To assess the causative role of non-sporing anaerobes in cass of erosive balanoposthitis, anaerobic culture was performed on purulent discharges from 104 patients with penile ulceration, a foul-smelling discharge, and a mixed and motile bacterial flora. Most of 29 culturally confirmed infections were due to mixed anaerobes and eight to single anaerobes. A rapid response to treatment with metronidazole also confirmed the anaerobic cause of the infection. Thus, acute anaerobic balanoposthitis can be readily diagnosed clinically and is easily treated.
Topics: Balanitis; Eikenella corrodens; Fusobacterium; Humans; Male; Metronidazole; Prevotella melaninogenica
PubMed: 6121604
DOI: 10.1136/bmj.284.6319.859 -
Infection and Immunity Jul 1997Hemolysins have been proven to be important virulence factors in many medically relevant pathogenic organisms. Their production has also been implicated in the etiology...
Hemolysins have been proven to be important virulence factors in many medically relevant pathogenic organisms. Their production has also been implicated in the etiology of periodontal disease. Hemolytic strain 361B of Prevotella melaninogenica, a putative etiologic agent of periodontal disease, was used in this study. The cloning, sequencing, and characterization of phyA, the structural gene for a P. melaninogenica hemolysin, is described. No extensive sequence homology could be identified between phyA and any reported sequence at either the nucleotide or amino acid level. As predicted from sequence analysis, this gene produces a 39-kDa protein which has hemolytic activity as measured by zymogram analysis. Unlike many Ca2+-dependent bacterial hemolysins, both the cloned and native PhyA proteins were enhanced by the presence of EDTA in a dose-dependent fashion with 40 mM EDTA allowing maximum activity. Ca2+ and Mg2+ were found to be inhibitory. The hemolytic activity also was found to have a dose-dependent endpoint. Through recovery of hemolytic activity from a spent reaction, this endpoint was shown to be the result of end product inhibition. This is the first report describing the cloning and sequencing of a gene from P. melaninogenica.
Topics: Amino Acid Sequence; Base Sequence; Blotting, Western; Cloning, Molecular; Genes, Bacterial; Hemolysin Proteins; Molecular Sequence Data; Prevotella melaninogenica
PubMed: 9199448
DOI: 10.1128/iai.65.7.2765-2771.1997 -
International Journal of Molecular... Apr 2018Bovine postpartum diseases remain one of the most significant and highly prevalent illnesses with negative effects on the productivity, survival, and welfare of dairy...
Bovine postpartum diseases remain one of the most significant and highly prevalent illnesses with negative effects on the productivity, survival, and welfare of dairy cows. Antibiotics are generally considered beneficial in the treatment of endometritis; however, frequent usage of each antibiotic drug is reason for the emergence of multidrug resistance (MDR) of the pathogenic microorganisms, representing a major impediment for the successful diagnosis and management of infectious diseases in both humans and animals. We synthesized silver nanoparticles (AgNPs) with an average size of 10 nm using the novel biomolecule apigenin as a reducing and stabilizing agent, and evaluated the efficacy of the AgNPs on the MDR pathogenic bacteria and isolated from uterine secretion samples. AgNPs inhibited cell viability and biofilm formation in a dose- and time-dependent manner. Moreover, the metabolic toxicity of the AgNPs was assessed through various cellular assays. The major toxic effect of cell death was caused by an increase in oxidative stress, as evidenced by the increased generation of reactive oxygen species (ROS), malondialdehyde, protein carbonyl content, and nitric oxide. The formation of ROS is considered to be the primary mechanism of bacterial death. Therefore, the biomolecule-mediated synthesis of AgNPs shows potential as an alternative antimicrobial therapy for bovine metritis and endometritis.
Topics: Animals; Anti-Bacterial Agents; Antioxidants; Apigenin; Arcanobacterium; Biofilms; Biomarkers; Cattle; Cattle Diseases; DNA; Dose-Response Relationship, Drug; Endometritis; Female; Metal Nanoparticles; Microbial Sensitivity Tests; Oxidation-Reduction; Oxidative Stress; Prevotella melaninogenica; RNA; Silver; Time Factors
PubMed: 29659523
DOI: 10.3390/ijms19041210 -
Microbial Pathogenesis Nov 2023Increasing studies have shown that the imbalance of the respiratory microbial flora is related to the occurrence of COPD, the severity and frequency of exacerbations and...
BACKGROUND
Increasing studies have shown that the imbalance of the respiratory microbial flora is related to the occurrence of COPD, the severity and frequency of exacerbations and mortality.However, it remains unclear how the sputum microbial flora differs during exacerbations in COPD patients manifesting emphysema phenotype, chronic bronchitis with emphysema phenotype and asthma-COPD overlap phenotype.
METHODS
Sputum samples were obtained from 29 COPD patients experiencing acute exacerbations who had not received antibiotics or systemic corticosteroids within the past four weeks.Patients were divided into three groups;emphysema phenotype(E);chronic bronchitis with emphysema phenotype(B+E) and asthma-COPD overlap phenotype(ACO).We utilized metagenomic Next Generation Sequencing (mNGS) technology to analyze the sputum microbial flora in COPD patients with different phenotypes during exacerbations.
RESULTS
There was no significant difference in alpha diversity and beta diversity among three groups.The microbial flora composition was similar in all three groups during exacerbations except for a significant increase in Streptococcus mitis in ACO.Through network analysis,we found Candidatus Saccharibacteria oral taxon TM7x and Fusobacterium necrophorum were the core nodes of the co-occurrence network in ACO and E respectively.They were positively correlated with some species and play a synergistic role.In B+E,Haemophilus pittmaniae and Klebsiella pneumoniae had a synergistic effect.Besides,some species among the three groups play a synergistic or antagonistic role.Through Spearman analysis,we found the relative abundance of Streptococcus mitis was negatively correlated with the number of hospitalizations in the past year(r = -0.410,P = 0.027).We also observed that the relative abundance of Prevotella and Prevotella melaninogenica was negatively correlated with age(r = -0.534,P = 0.003;r = -0.567,P = 0.001),while the relative abundance of Streptococcus oralis and Actinomyces odontolyticus was positively correlated with age(r = 0.570,P = 0.001;r = 0.480,P = 0.008).In addition,the relative abundance of Prevotella melaninogenica was negatively correlated with peripheral blood neutrophil ratio and neutrophil to lymphocyte ratio(r = -0.479,P = 0.009;r = -0.555,P = 0.002),while the relative abundance of Streptococcus sanguinis was positively correlated with peripheral blood neutrophil ratio and neutrophil to lymphocyte ratio (r = 0.450,P = 0.014;r = 0.501,P = 0.006).There was also a significant positive correlation between Oribacterium and blood eosinophil counts(r = 0.491,P = 0.007).
CONCLUSION
Overall,we analyzed the sputum microbiota of COPD patients with different phenotypes and its relationship with clinical indicators, and explored the relationships between microbiota and inflammation in COPD.We hope to alter the prognosis of patients by inhibiting specific bacterial taxa related to inflammation and using guide individualized treatment in the future research.
Topics: Humans; Bronchitis, Chronic; Sputum; Pulmonary Disease, Chronic Obstructive; Phenotype; Asthma; Emphysema; Inflammation
PubMed: 37673353
DOI: 10.1016/j.micpath.2023.106335 -
Infection 2000Pyomyositis is an uncommon infection in temperate climates, however, it is being more frequently reported among patients with diabetes or malignancy, or those who are...
Pyomyositis is an uncommon infection in temperate climates, however, it is being more frequently reported among patients with diabetes or malignancy, or those who are immunocompromised. It is predominantly caused by Staphylococcus aureus, and rarely by Bacteroides species. Pyomyositis due to Prevotella melaninogenica has not previously been reported. We describe an elderly patient with pyomyositis of the thigh due to P. melaninogenica which was successfully treated by surgical incision and drainage in combination with metronidazole therapy.
Topics: Aged; Anti-Bacterial Agents; Bacteroidaceae Infections; Drainage; Female; Humans; Metronidazole; Myositis; Prevotella melaninogenica; Thigh
PubMed: 10697793
DOI: 10.1007/s150100050012