Streptococcus Salivarius Research Articles

Uncovering the arsenal of class II bacteriocins in salivarius streptococci.

Facing the antibiotic resistance crisis, bacteriocins are considered as a promising alternative to treat bacterial infections. In the human commensal Streptococcus salivarius, the production of unmodified bacteriocins (or salivaricins) is directly controlled at the transcriptional level by quorum-sensing. To discover hidden bacteriocins, we harnessed here the unique molecular signatures of salivaricins not yet used in available computational pipelines and performed genome mining followed by orthogonal reconstitution and expression. From 100 genomes of S. salivarius, we identified more than 50 bacteriocin candidates clustered into 21 groups. Strain-based analysis of bacteriocin combinations revealed significant diversity, reflecting the plasticity of seven independent loci. Activity tests showed both narrow and broad-spectrum bacteriocins with overlapping activities against a wide panel of Gram-positive bacteria, including notorious multidrug-resistant pathogens. Overall, this work provides a search-to-test generic pipeline for bacteriocin discovery with high impact for bacterial ecology and broad applications in the food and biomedical fields.

Streptococcus salivarius pneumonia-associated pneumomediastinum: a case report and literature review

BackgroundStreptococcus salivarius is an opportunistic pathogen, and there have been no reported cases of Streptococcus salivarius pneumonia to date. Pneumomediastinum is usually secondary to tracheal or esophageal injury and is very rare as a complication of pneumonia. We report a case of Streptococcus salivarius pneumonia complicated by pneumomediastinum, aiming to enhance clinicians’ awareness of rare pathogens and uncommon complications in pneumonia.Case presentationThe patient, a 36-year-old male, presented with a persistent cough and sputum production for one week, accompanied by a sore throat that had developed just one day prior. Chest computed tomography (CT) disclosed pneumomediastinum alongside obstructive atelectasis in the left lower lobe. Streptococcus salivarius infection was conclusively identified through bronchoalveolar lavage metagenomic next-generation sequencing (mNGS), as well as smear and culture analyses. The patient was administered intravenous amoxicillin-clavulanate potassium for a duration of seven days as part of the anti-infection regimen. Given the stability of the patient’s respiratory and circulatory systems, a tube drainage procedure was deemed unnecessary. Post-treatment, the patient’s clinical symptoms notably improved. A subsequent chest CT scan revealed the re-expansion of the left lower lung and near-complete resolution of pneumomediastinum.ConclusionThere are numerous pathogens that can cause pneumonia. While focusing on common pathogens, it is important not to overlook rare ones. When considering infections from rare pathogens, it is recommended to promptly perform a bronchoscopy and submit bronchoalveolar lavage fluid for mNGS to improve pathogen detection rates. During the diagnosis and treatment of pneumonia, it is crucial to be vigilant for rare complications. When a patient presents with symptoms such as dyspnea or subcutaneous emphysema, it is advisable to immediately perform a chest CT scan to rule out pneumomediastinum.

Features of the oropharyngeal microbiota of healthy children and those with acute respiratory infections. A prospective single-center randomized study

Background. The oropharyngeal microbiota is involved in the development of colonization resistance, affecting viral adhesion and metabolism. Any deviations in the stability of the environmental microbial niches of the oropharynx alter the local immune response and can trigger severe chronic somatic disorders. Aim. To compare the composition of the microbiota of children during an episode of respiratory infection and healthy volunteers examined in different periods of convalescence. The obtained data can be used to predict the course of the disease, analyze the risk of complications, and assess the frequency of the diseases in the future. Materials and methods. From 20.01.2022 to 23.12.2022, an open-label prospective single-center randomized comparative study was conducted, which included 120 children aged 5-10 who presented with symptoms of acute respiratory infection. The control group consisted of 15 asymptomatic children examined at different periods of convalescence. The study compared changes in the oral microbiota composition of patients and healthy children. The evaluation was performed using complete 16S rRNA gene sequencing on the Oxford Nanopore platform. Taxonometric analysis at the species and genera level was performed using the Knomics-Biota platform. The R programming language was used for statistical processing. In addition, the parameters of α- and β-diversity of the microbiota were assessed. The Chao1 and Shannon indices were calculated to assess α-diversity (diversity within one community). The Chao1 index is based on the number of species found in the sample and also rare species that are found only 1 or 2 times, thus preventing underestimation of diversity. The Shannon index includes both the number of species and their uniformity in the community. A change in the index indicates the dominance of one or more species. The following indicators were used to assess the β-diversity describing the differences between two microbiota samples at the species and genera level: Bray–Curtis dissimilarity (characterizing the ratios of common and different microorganisms between the samples) and the Aitchison distance (reflecting the differences in the proportions of microorganisms). In addition, the balance between the two groups of microorganisms was evaluated using the NearesBalance method, which characterizes the differences between the microbiota of the main and control groups. Results. The results of our study show that during respiratory infection, the state of the oropharyngeal microbiota is characterized by an increase in α-diversity, which is associated with an increase in the proportion of species of Streptococcus salivarius, Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus pyogenes, Streptococcus thermophilus and A12 versus the proportion of Streptococcus mitis, Streptococcus oralis, Streptococcus gwangjuense, Streptococcus sanguinis, Streptococcus gordonii and FDAARGOS_192. In the control group, the oropharyngeal microbiota was divided into two clusters. The dominance of streptococci was observed in the first group (control), while the second group had a more uniform representation. Analysis of the changes in microbial communities in the main and control groups can show the stages of oral microbiota recovery after an acute respiratory infection episode. Conclusion. More research is needed in the field of the oropharyngeal microbiome on a larger sample of healthy children, to standardize the communities of the oropharyngeal microbiota, to study the interaction within communities and with the body as a whole. Analysis of the impact of the microbiota on the frequency and course of respiratory infections and the rate of complications opens up new prospects in treating, rehabilitating, and preventing diseases. These research areas can contribute to improving children's health and quality of life and introducing new approaches into clinical practice.

Does gut microbiota dysbiosis impact the metabolic alterations of hydrogen sulfide and lanthionine in patients with chronic kidney disease?

BackgroundChronic Kidney Disease (CKD) is characterized by a methionine-related metabolic disorder involving reduced plasma levels of hydrogen sulfide (H2S) and increased lanthionine. The gut microbiota influences methionine metabolism, potentially impacting sulfur metabolite dysfunctions in CKD. We evaluated whether gut microbiota dysbiosis contributes to H2S and lanthionine metabolic alterations in CKD.MethodsThe gut microbiota of 88 CKD patients (non-dialysis, hemodialysis, and transplant patients) and 26 healthy controls were profiled using 16 S-amplicon sequencing. H2S and lanthionine concentrations were measured in serum and fecal samples using the methylene blue method and LC-MS/MS, respectively.ResultsThe CKD population exhibited a tenfold increase in serum lanthionine associated with kidney dysfunction. Despite lanthionine retention, hemodialysis and transplant patients had significantly lower serum H2S than healthy controls. Fecal H2S levels were not altered or related to bloodstream H2S concentrations. Conversely, fecal lanthionine was significantly increased in CKD compared to healthy controls and associated with kidney dysfunction. Microbiota composition varied among CKD groups and healthy controls, with the greatest dissimilarity observed between hemodialysis and transplant patients. Changes relative to the healthy group included uneven Ruminococcus gnavus distribution (higher in transplant patients and lower in non-dialysis CKD patients), reduced abundance of the short-chain fatty acid-producing bacteria Alistipes indistinctus and Coprococcus eutactus among transplant patients, and depleted Streptococcus salivarius in non-dialysis CKD patients. A higher abundance of Methanobrevibacter smithii, Christensenella minuta, and Negativibacillus massiliensis differentiated hemodialysis patients from controls. No correlation was found between differentially abundant species and the metabolic profile that could account for the H2S and lanthionine alterations observed.ConclusionsThe metabolic deregulation of H2S and lanthionine observed in the study was not associated with alterations in the gut microbiota composition in CKD patients. Further research on microbial sulfur pathways may provide a better understanding of the role of gut microbiota in maintaining H2S and lanthionine homeostasis.

Efficacy of Streptococcus salivarius Blis K12 in the Prevention of Upper Respiratory Tract Infections in Physically Active Individuals: A Randomized Controlled Trial

This study investigates the efficacy of Streptococcus salivarius K12 in preventing upper respiratory tract infections (URTIs) in healthy adults. URTIs are a common issue, particularly in physically active individuals, leading to significant disruptions in daily life. Probiotics, such as S. salivarius K12, have emerged as a potential preventive strategy for these infections. This research was conducted as a randomized, double-blind, placebo-controlled trial involving 112 participants aged between 19 and 25. Participants were randomly divided into two groups: one group received a daily dose of S. salivarius K12, marketed as Bactoblis®, while the other received a placebo. The trial lasted for four months, during which adherence to the treatment protocol was closely monitored. The primary goal was to measure the incidence of URTIs using the Jackson Scale and the Wisconsin Upper Respiratory Symptom Survey (WURSS-11). The results indicated that higher adherence to the S. salivarius K12 treatment was associated with an increased number of days without URTI symptoms. Although the overall severity of symptoms did not differ significantly between the treatment and control groups, those with high adherence to S. salivarius K12 (greater than 90%) reported more days free from illness. In conclusion, S. salivarius K12 demonstrated potential as a preventive measure against URTIs, especially in individuals who adhered strictly to the treatment regimen. However, further research involving larger populations and longer follow-up periods is needed to fully confirm these findings and better understand the role of S. salivarius K12 in preventing respiratory infections.

Spectroscopic analysis of wild medicinal desert plants from wadi sanor (beni-suef), Egypt, and their antimicrobial and antioxidant activities

Desert plants possess untapped potential for medicinal applications due to their rich phytochemical profiles. However, they need to be more explored. Thus, this study integrates advanced analytical, biochemical, and molecular techniques to investigate the phytochemical composition and biological activities (antimicrobial and antioxidant) of four desert plants (Pergularia tomentosa, Zygophyllum coccineum, Pulicaria undulata, and Ochradenus baccatus), collected from Wadi Sannor, Beni-Suef Governorate, Egypt, in March 2021. The volatile chemicals in the 70 % ethanol extracts of the selected plants were also analyzed using GC-MS. The extract exhibited strong antioxidant properties, as demonstrated by its FRAP (Ferric reducing ability of plasma) values, anti-lipid peroxidation, superoxide anion scavenging activity, and DPPH scavenging activity. Additionally, plants extracts showed high antimicrobial activities against seven pathogens, including three Gram-negative bacteria (Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli) and four Gram-positive bacteria (Staphylococcus saprophyticus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus salivarius). Lastly, molecular docking was conducted for cis-vaccenic acid, (E)-9-octadecenoic acid, the cyclohepta[b]furan-2-one scaffold, and URS-20(30)-en-3-ol against both the thymidylate kinase enzyme and the active sites of E. coli DNA gyrase. The results from the molecular docking studies showed a strong correlation with the biological data. Moreover, these compounds exhibited good, proposed absorption, distribution, metabolism, and excretion–toxicity (ADMET) profiles. Our study highlights the potential of P. tomentosa, Z. coccineum, P. undulata, and O. baccatus for future medical applications and the development of new pharmaceuticals derived from desert flora.

Oral microbiocenosis state under different approaches of replacing dental crown defects

Dental caries is one of the most common health problems. The aim of the research was to study the spectrum of microbiota, which is part of the dental biofilm, and its biological properties. The study involved 90 participants of the study group and 20 of the control group. Dental plaque and saliva were used as principal clinical specimens. The main research method was bacteriological. All samples from study participants were positive for microbiota. At the initial collection of material, 395 unique isolates were obtained: 338 from patients with caries and 57 from healthy volunteers. The microbiocenosis of the oral cavity associated with the development of caries contained such eudodominants as Streptococcus mutans, Peptostreptococcus spp., Fusobacterium spp., Prevotella spp. and dominants Streptococcus pyogenes, Enterobacterales, Prevotella spp. and Candida albicans. In contrast the eudominants of the healthy oral cavity were microorganisms with known commensal properties, in particular Streptococcus salivarius, Aerococcus viridans, Veillonella spp. After the dental treatment, significant shifts in the taxonomic composition of the dental biofilm were observed. Therefore, the composition of the oral cavity microbiocenosis in participants who underwent restoration of the dental crown defects with zirconium inserts approached patients to the healthy cohort participants. The eudodominants of the oral microbiocenosis of the participants who underwent direct restoration were S. mitis, Peptostreptococcus spp. and Veillonella spp. In zirconium restoration, the commensals S. salivarius and A. viridans were eudodominants. The obtained isolates of opportunists possessed high virulence properties. Streptococcus spp. cultures were sensitive to norfloxacin screening in only 28.6% of cases. Among cultures of the genus Staphylococcus, 23.8% were methicillin resistant. Representatives of Enterobacterales had chemotherapeutic sensitivity that varied significantly depending on the group of antimicrobial agents. Using disks with phenylboronic acid, ethylenediaminetetraacetic acid and cloxacillin, it was established that Klebsiella spp. were producers of class A carbapenemases (n=3) and contained AmpC (n=3). Carbapenemases were also produced by at least 65.2% of the studied cultures of non-fermenting gram-negative microorganisms. In our study, all obtained isolates were also endowed with the ability to form a biofilm. Therefore, microbiological research in dentistry should be considered as one of the objective methods for assessment of health of the oral cavity and will also have advantages in choosing a method of correcting defects of dental crown parts and in some cases, making an informed decision about the prescription of antimicrobial treatment.

Roles of oral and gut microbiota in acute myocardial infarction

IntroductionThe significance of oral/gut microbiota in acute myocardial infarction (AMI) has been increasingly appreciated. However, correlations between oral/gut microbiota and AMI parameter, as well as the key microbiota that may have a crucial function in this process, remain unclear. ObjectivesTo investigate the composition and structure of oral and gut microbiota associated with AMI and explore the roles of specific bacterial species in the progression of AMI. MethodsWe conducted a case-control study with 37 AMI patients and 36 controls. Oral and gut sample were collected and sequenced. Using correlation analysis, we combined bioinformatics data with AMI clinical parameters and obtained heatmaps of correlation coefficients. Additionally, we used antibiotics to eliminate the gut microbiota of C57BL/6J mice, followed by the transplantation of selected bacteria to verify the gut colonization of oral bacteria and their impact on AMI. ResultsThe component of oral and gut microbiota of AMI group showed significant alterations when compared to the control group. 17 salivary genera, 21 subgingival genera, and 8 gut genera in AMI group substantially differed from those in control group. Additionally, 19 genera from saliva, 19 genera from subgingival plaque, and 11 genera from feces substantially correlated with AMI clinical parameters. Orally administrated S.o (Streptococcus oralis subsp. dentisani), S.p (Streptococcus parasanguinis), and S.s (Streptococcus salivarius) were able to colonize in the gut and exacerbate myocardial infarction. ConclusionThere is a strong correlation between oral/gut microbiota and AMI. Streptococcus spp. is capable to transmit from oral to gut and exacerbate myocardial infarction in mice. Monitoring and control of specific oral microbiota may be an effective new strategy for improving the therapy of AMI.

Adsorptive potential of dispersible chitosan-coated biogenic iron oxide nanocomposite for enhanced anti-bacterial activity against gram-positive and gram-negative bacterial pathogens

The use of various biomaterials, such as plants or microbes, to create nanoparticles (NPs), is seen as a viable strategy in green nanotechnology. The synthesis of low-cost, energy-efficient, nontoxic, ecologically acceptable metallic nanoparticles has recently become a critical topic. The biosynthesis of iron oxide NPs using pomegranate peel extract has been investigated. Biogenic iron oxide NPs were coated with highly porous chitosan as a supporting material to enhance applicability of NPs for wastewater remediation. Biogenic magnetic NPs and its composite were characterized by scanning electron microscope, X-ray diffraction, and Fourier Transformer Infrared spectroscopy (FTIR). Our study focused on the ability of biogenic magnetite Fe3O4 NPs and its bio-composite for removal of As+5 ions from wastewater. Adsorption isotherms were obtained using metal ion concentrations ranging from 5 to 25 mg/L. The Langmuir adsorption model was validated by our data. The reaction kinetics of the adsorption process were pseudo-second order. Interestingly, the bio-composite achieved 90% As+5 removal at pH4. In addition, the prepared nanocomposite was characterized using various analytical techniques to confirm its physicochemical properties. The adsorptive capacity of the nanocomposite was evaluated by studying the removal of pollutants and contaminants from aqueous solutions. Additionally, the antibacterial activity of the nanocomposite was assessed against a panel of clinically relevant Gram-positive and Gram-negative bacterial strains, including Staphylococcus epidermidis (RCMB 9241, ATCC 12228), Staphylococcus saprophyticus (RCMB 010028, ATCC 15305), Enterococcus faecalis (RCMB 010052), Streptococcus salivarius (ATCC 13415), Escherichia coli (RCMB 010052, ATCC 25922), Salmonella enterica serovar Typhimurium (RCMB 006(1), ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853). Our findings have important implications in the field of low-cost, easy, and environmentally friendly water bioremediation.

THE EFFECTIVENESS OF THE IMMUNE-BOOSTING PREPARATIONS IN PREVENTION AND TREATMENT OF RESPIRATORY INFECTIONS

Respiratory infections are undoubtedly one of the most common diseases that both primary care physicians and specialists working in hospitals have to deal with. The percentage of these diseases is particularly high in children and, depending on the child's age, may range from 6% to even 25%. A major clinical problem is the recurrent nature of these infections and their complications. This results in receiving an increased number of medications that can cause numerous side effects. Overprescription of antibiotics and consequently, increase of antibiotic resistance are also observed. Looking forward, the prevention of the recurrent infections is the key problem. The aim of our work was to evaluate the efficacy of the most popular preparations available on the pharmaceutical market that can improve immunity and complement conventional methods of treating infections or completely replace them. These include: elderberry, β-Glucans, lactoferrin, colostrum, black cumin preparations, echinacea, propolis, Streptococcus salivarius K12, inosine pranobex, ginseng, OM-85 bacterial lysate. We reviewed the literature from 2012 to 2024 using Pubmed and Google Scholar. The assesment of the effectiveness of preparations for immunity was based primarily on the systematic reviews, meta-analyses and randomised controlled trials. The above-mentioned preparations are largely characterized by a positive impact on improving the immunity of people supplementing them by activating non-specific immunity mechanisms. Thanks to this, some of the respondents can observe the regulation of the body's inflammatory response and, consequently, a decrease in the number of infections and their course. Due to the still insufficient number of studies on these preparations and the discrepancies in the results obtained among authors, further researches are needed to take a clear stance on their effectiveness.

Microbial load of facilities for keeping pigs of different production groups

The study analyzed the microbial load of objects in the facilities where pigs of different production groups were kept at the final stage of production cycles, immediately before disinfection measures. The study found that the number of mesophilic aerobic and facultative anaerobic microorganisms (MAFAnM) in the swabs from the surfaces of the studied objects varied from 5.00 to 6.88 log CFU/cm³. The lowest quantity of bacteria was found on drinkers and feeders, while the highest quantity was on the facilities’ floor. The average level of microbial load in the facilities for keeping sows, farrowing, and growing piglets ranged from 5.91 to 6.07 log CFU/cm³. The highest values were observed for the study of swabs taken in the piglet-rearing facility. The proportion of field isolates of the rod, cocci, and spiral shapes of microorganisms in the rearing facility was 62.1%, 28.8%, and 9.1%, respectively, in the farrowing facility — 63.9%, 29.2%, and 6.9%, and in the sow housing facility — 66.2%, 26%, and 7.8%. Escherichia coli was dominant in the rearing facility — 13.9% of isolates, Proteus mirabilis, Bacillus subtilis, and Campylobacter jejuni — 9.7% each, and Citrobacter freundii, Enterococcus faecalis, and Enterococcus faecium — 8.3% each. In farrowing facilities, the proportion of E. coli isolates was 16.6%. 7.5% fewer isolates belonged to B. subtilis, Streptococcus salivarius, and C. jejuni, and 9% fewer isolates belonged to Klebsiella pneumoniae, P. mirabilis, E. faecalis, and E. faecium. In the sow housing facility, the proportion of E. coli isolates was 12.9%, the number of P. mirabilis isolates was 1.2% less, and C. freundii was 3.8% less

Specific Synbiotic Sugars Stimulate Streptococcus salivarius BLIS K12 and BLIS M18 Lantibiotic Production to Expand Bacterial Inhibition Range and Potency

Synbiotics are mixtures of prebiotics and probiotics that enhance the activity of probiotic bacteria when co-administered to provide greater benefits to the host. Traditionally, the synbiotics that have been discovered enhance gut probiotic strains and are nutritionally complex molecules that survive digestive breakdown until they reach the later stages of the intestinal tract. Here, we screened and identified sugars or sugar substitutes as synbiotics for the oral probiotic strains Streptococcus salivarius BLIS K12 and BLIS M18. Using a modified deferred antagonism assay, we found that 0.5% (w/v) galactose and 2.5% (w/v) raffinose were the best candidates for use as synbiotics with BLIS K12 and M18, as they trigger enhanced antimicrobial activity against a range of bacteria representing species from the mouth, gut, and skin. Using reverse transcriptase quantitative PCR, we found that this enhanced antimicrobial activity was caused by the upregulation of the lantibiotic genes salA, salB, and sal9 in either K12 or M18. This led to the conclusion that either 2.5% (w/v) raffinose or 0.5% (w/v) galactose, respectively, are suitable synbiotics for use in conjunction with BLIS K12 and M18 to enhance probiotic performance.

Lapidilactobacillus salsurivasis sp. nov., Secundilactobacillus muriivasis sp. nov., and Streptococcus parasalivarius sp. nov., isolated from Traditional Chinese Pickle.

Four Gram-stain-positive bacterial strains (designated 475-2T, 46-6BT, 778-2T and A810-3), isolated from traditional Chinese pickle, were characterized using a polyphasic taxonomic approach. Strain 475-2T was most closely related to the type strain of Lapidilactobacillus achengensis, having 99.9% 16S rRNA gene sequence similarity, 94.1-95.1% average nucleotide identity (ANI) and 57.6% digital DNA-DNA hybridization (dDDH) values. Strain 46-6BT was most closely related to the type strain of Secundilactobacillus similis, having 99.8% 16S rRNA gene sequence similarity, 94.3-94.9% ANI and 58.9-59.2% dDDH values. Strains 778-2T and A810-3 were phylogenetically related to the type strains of Streptococcus salivarius, Streptococcus thermophilus and Streptococcus vestibularis, having 99.7-99.9% 16S rRNA gene sequence similarities, 89.1-94.4% ANI and 39.0-55.5% dDDH values. Based upon the data obtained in the present study, three novel species, Lapidilactobacillus salsurivasis sp. nov., Secundilactobacillus muriivasis sp. nov. and Streptococcus parasalivarius sp. nov., are proposed and the type strains are 475-2T (= JCM 36613T = CCTCC AB 2023258T = LMG 33412T), 46-6BT (= JCM 36612T = CCTCC AB 2023259T = LMG 33411T) and 778-2T (= JCM 36614T = CCTCC AB 2023257T = LMG 33413T), respectively.

Comparison of Dracocephalum Moldavica Essential Oil with Chlorhexidine on Cariogenic Bacteria.

Dental caries and periodontal disease are the most common oral problems. Chemical antibacterial agents often have side effects; thus, researchers have long been in search for organic and herbal products to prevent dental caries and periodontal disease. The present study has aimed to assess the effects of Dracocephalum moldavica essential oil on Streptococcus mutans, Streptococcus salivarius, Streptococcus sobrinus, and Lactobacillus acidophilus compared to Chlorhexidine (CHX). In this in vitro study, the plants were collected from Zanjan Province, Iran. Analysis of the essential oil was carried out by gas chromatography/mass chromatography. Micro-broth dilution and disc diffusion methods were used for assessment of the antimicrobial activity, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. The mean diameter of the growth inhibition zones in the well plate method for Dracocephalum moldavica showed that it had greater antimicrobial activity against Lactobacillus acidophilusthan others (p Value= 0.01). Furthermore, Dracocephalum moldavica had higher antimicrobial activity than CHX. The results of MIC and MBC showed that Dracocephalum moldavica had lower antibacterial activity than CHX. Dracocephalum moldavica essential oil demonstrated antibacterial properties against cariogenic bacteria. Given that other favorable properties of these essential oils are confirmed, they may be suitable for use as antibacterial agents in the formulation of oral healthcare products.

Changes in Innate Immunity and Microbiome in Different Aging Phenotypes.

The indicators of innate immunity and the composition of the microbiome in the nasopharyngeal mucosa in centenarians with different aging phenotypes were analyzed. A significant increase in the expression of pattern-recognizing receptor genes (TLR2, TLR4, and NLRP3) and proinflammatory cytokines (IL1B, IL18) was shown in the group of centenarians with pathological aging phenotype. In centenarians with successful aging phenotype, increased diversity of the microbiome composition was observed. At the same time, a moderate inverse correlation was found between an increase in the growth of the commensal bacterium Streptococcus salivarius and a decrease in the expression of proinflammatory cytokine genes IL1B and IL18. These findings can serve as biomarkers for the timely identification of the phenotype of aging in senile and elderly people.

Application of Prebiotics and Probiotics to Improve Oral and Dental Health by Inhibiting Streptococcus mutans

Background: The most common method to combat microorganisms that cause tooth decay is the use of antibiotics. However, despite the benefits of antibiotics, their use has significant disadvantages, such as the increased resistance of microorganisms to these chemicals. Objectives: A promising and safer alternative is the use of probiotics and prebiotics, which can reduce or inhibit the growth of disease-causing oral microorganisms. Streptococcus salivarius is one such probiotic, while inulin and nisin are the prebiotics commonly recommended for this purpose. Methods: Several assays, including agar bilayer interference, agar well penetration, and microdilution, were used to assess the antibacterial activities of S. salivarius K12 and S. salivarius M18 probiotics, as well as those of the prebiotics nisin and inulin. Additionally, bile salt and low pH tolerance assessments were conducted for the probiotics, and the synthesis of bacteriocins by the probiotics was verified using proteolytic and enzymatic activity assays. Results: The minimum inhibitory concentration (MIC) assay revealed that Streptococcus mutans growth was inhibited by S. salivarius K12 and S. salivarius M18 at a concentration of 75%, and by nisin and inulin at 200 IU/mL. In the well penetration assay, S. salivarius K12 exhibited significantly better results compared to S. salivarius M18. Nisin had significantly greater inhibitory effects on S. mutans compared to inulin. A combination of all four components (S. salivarius K12, S. salivarius M18, nisin, and inulin) resulted in maximum antibacterial activity, indicating a synergistic effect. Based on the agar bilayer assay and the growth inhibition zone diameters, nisin showed the highest antibacterial activity against S. mutans, followed by S. salivarius K12, inulin, and S. salivarius M18. Enzymatic digestion and proteolytic activity assays confirmed the synthesis of bacteriocins by S. salivarius K12 and S. salivarius M18. Both probiotics demonstrated bile salt tolerance at a concentration of 0.3% and surviving rates of 36% and 33%, respectively, at pH 2. Conclusions: The most important finding of the current study is the synergistic effect between the highlighted prebiotics and probiotics, which may offer a novel and effective combination for preventing tooth decay.

Green engineering of MgO nanoparticles: Assessment of their antioxidant and antibacterial activity against dental pathogens

Green engineering antibacterial nanoparticles have been synthesized using environmentally friendly plant extracts as nucleation agents due to their sustainability, biocompatibility and cost-effectiveness compared to conventional chemical methods. In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized using the marine plant Avicennia marina as a reducing agent. The green synthesized MgO NPs were characterized for their structural, optical, morphological, and thermal properties using XRD, UV–Vis, TGA-DTA, SEM, and TEM characterization techniques. Our biomedical studies revealed that MgO NPs hold significant promise, demonstrating potent antibacterial and antioxidant properties. In the DPPH assay, MgO NPs antioxidant activity effectively neutralized free radicals. Furthermore, their antimicrobial activity was tested against dental bacterial pathogens, showing strong inhibitory effects on Streptococcus mutans, Streptococcus mitis, Porphyromonas gingivalis, and Streptococcus salivarius microorganisms. These findings underscore the potential of MgO NPs for a range of applications, particularly in the fields of dentistry and antioxidant research.

Oral microbiota autobacteriocins directed against pathogens of bacterial complications of respiratory infections

Recent years have been marked by a wide spread of respiratory viral infections, which are often accompanied by the development of bacterial complications. The greatest danger is posed by nosocomial strains with multidrug resistance. One of the ways to combat antibiotic-resistant strains is the possibility of using bacteriocins produced by certain bacteria that are present in the human body, food, and the environment. The most interesting are the strains of autobacteriocins isolated from the human's own normal microbiota, which does not have immune rejection. The purpose of the study: to investigate the antibacterial effect of autobacteriocins of the oral microbiota against the main pathogens of bacterial complications in respiratory infections. Six reference strains from the ESKAPE group (Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) and 18 multi-resistant strains of the same group isolated from the respiratory tract of individuals with bacterial complications of viral infections were examined. The study used bacteriological, molecular biological, and statistical methods, as well as mass spectrometric research method. The autobacteriocins isolated from Enterococcus faecalis, Streptococcus salivarius, and Lactobacillus paracasei bacteria were the most effective against multidrug-resistant strains from the ESKAPE group. Notably, the concentration of bacteriocin-producing bacteria in the medium of co-cultivation was 500 and 1,000 times less than the strains against which they were directed. Suppression of the growth of multidrug-resistant strains by 2-3 times compared with the initial one was observed after 2 hours. Thus, the antibacterial effectiveness of autobacteriocins against resistant strains of bacteria isolated from the same individual suggests the possibility of a personalized approach to obtaining and using autoprobiotic strains of bacteria to combat bacterial complications of the respiratory tract.

Genetic Patterns of Oral Cavity Microbiome in Patients with Sickle Cell Disease.

The Middle Eastern prevalence of sickle cell anemia, a genetic disorder that affects red blood cells, necessitates additional research. On a molecular level, we sought to identify and sort the oral microbiota of healthy individuals and those with sickle cell anemia. Furthermore, it is crucial to comprehend how changes in the genetic makeup of the oral microbiota impact the state of sickle cell anemia. Using next-generation sequencing, the 16S rRNA amplicon was examined using saliva samples from 36 individuals with sickle cell anemia and healthy individuals. These samples were obtained from sickle cell anemia patients (18 samples) and healthy control participants (controls, 18 samples). Various analyses are conducted using bioinformatic techniques to identify distinct species and their relative abundance. Streptococcus, followed by Fusobacterium nucleatum, Prevotella, and Veillonella were the most prevalent genera of bacteria in the saliva of the SCA and non-SCA individuals according to our findings. Rothia mucilaginosa, Prevotella scoposa, and Veillonella dispar species were the dominant species in both sickle cell anemia and non-sickle cell anemia subjects. Streptococcus salivarius, Actinomyces graevenitzii, Actinomyces odontolyticus, and Actinomyces georgiae spp. were the most prevalent bacterial spp. in the studied SCA cases. The sequencing of the 16S rRNA gene yielded relative abundance values that were visualized through a heatmap analysis. Alterations in the oral microflora's constitution can significantly affect the susceptibility of sickle cell anemia patients to develop more severe health complications. Salivary diagnosis is a potential tool for predicting and preventing oral microbiome-related diseases in the future.

Activity of N-Chlorotaurine against Periodontal Pathogens.

Dental plaque bacteria play an important role in the pathogenicity of periodontitis and peri-implantitis. Therefore, antimicrobial agents are one means of treatment. N-chlorotaurine (NCT) as an endogenous well-tolerated topical antiseptic could be of advantage for this purpose. Accordingly, its microbicidal activity against some dental plaque bacteria was investigated at therapeutic concentrations in vitro. In quantitative killing assays, the activity of NCT against planktonic bacteria and against biofilms grown for 48 h on implantation screws was tested. Electron microscopy was used to demonstrate the formation of biofilm and its morphological changes. The killing of planktonic bacteria of all tested species, namely Streptococcus sanguinis, Streptococcus salivarius, Streptococcus oralis, Streptococcus cristatus, Rothia aeria, and Capnocytophaga ochracea, was shown within 10-20 min by 1% NCT in 0.01 M phosphate-buffered saline at 37 °C. Bacteria grown on screws for 24 h were inactivated by 1% NCT after 15-20 min as well, but the formation of biofilm on the screws was visible in electron microscopy not before 48 h. The killing of biofilms by 1% NCT was demonstrated after 30 min (streptococci) and 40 min (R. aeria). As expected, NCT has broad activity against dental plaque bacteria as well and should be further investigated on its clinical efficacy in periodontitis and peri-implantitis.