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Journal of the American Heart... Nov 2023Acute ischemic stroke may be due to embolism from ruptured atherosclerotic carotid arteries. DNA of oral bacteria, mainly the viridans streptococci group, has been...
BACKGROUND
Acute ischemic stroke may be due to embolism from ruptured atherosclerotic carotid arteries. DNA of oral bacteria, mainly the viridans streptococci group, has been detected in thrombus aspirates of patients with ischemic stroke as well as in carotid endarterectomy samples. Because viridans streptococci are known to possess thrombogenic properties, we studied whether their presence in thrombus aspirates and in carotid artery specimens can be confirmed using bacterial immunohistochemistry.
METHODS AND RESULTS
Thrombus aspirates from 61 patients with ischemic stroke (70.5% men; mean age, 66.8 years) treated with mechanical thrombectomy, as well as carotid endarterectomy samples from 20 symptomatic patients (65.0% men; mean age, 66.2 years) and 48 carotid artery samples from nonstroke autopsy cases (62.5% men; mean age, 66.4 years), were immunostained with an antibody cocktail against 3 species (, and ) of viridans streptococci. Of the thrombus aspirates, 84.8% were immunopositive for viridans streptococci group bacteria, as were 80.0% of the carotid endarterectomy samples, whereas immunopositivity was observed in 31.3% of the carotid artery samples from nonstroke autopsies. Most streptococci were detected inside neutrophil granulocytes, but there were also remnants of bacterial biofilm as well as free bacterial infiltrates in some samples.
CONCLUSIONS
Oral streptococci were found in aspirated thrombi of patients with acute ischemic stroke as well as in carotid artery samples. Our results suggest that viridans streptococci group bacteria may play a role in the pathophysiology of ischemic stroke.
PubMed: 37982253
DOI: 10.1161/JAHA.123.030639 -
International Journal of Molecular... Oct 2023Bacterial surface proteins assembled into amyloids contribute to biofilm formation and host immune evasion. , a pioneer colonizer of teeth commonly involved in...
Bacterial surface proteins assembled into amyloids contribute to biofilm formation and host immune evasion. , a pioneer colonizer of teeth commonly involved in cardiovascular infections, expresses about thirty-three proteins anchored to the cell wall by sortase A. Here, we characterized the production of amyloid in strains differing in biofilm and immune evasion phenotypes and investigated the role of sortase A in amyloidogenesis. Amyloid was identified in biofilms formed by nine strains, using Congo red (CR) staining and cross-polarized light microscopy. Additionally, EGCG, an amyloid inhibitor, impaired biofilm maturation in a strain-specific fashion. The amounts of amyloid-like components quantified in culture fluids of nine strains using thioflavin T and fluorimetry negatively correlated with bacterial binding to complement-activating proteins (SAP, C1q), C3b deposition and rates of opsonophagocytosis in PMNs, implying amyloid production in immune evasion. The deletion of the sortase A gene () in strain SK36 compromised amyloid production and sucrose-independent biofilm maturation. The mutant further showed increased susceptibility to C3b deposition and altered interactions with PMNs as well as reduced persistence in human blood. These findings highlight the contribution of amyloids to biofilm formation and host immune evasion in strains, further indicating the participation of sortase A substrates in amyloidogenesis.
Topics: Humans; Streptococcus sanguis; Immune Evasion; Amyloid; Bacterial Proteins; Biofilms
PubMed: 37958670
DOI: 10.3390/ijms242115686 -
Dental Materials : Official Publication... Feb 2024Dental caries is caused by acids from biofilms. pH-sensitive nanoparticle carriers could achieve improved targeted effectiveness. The objectives of this study were to...
OBJECTIVES
Dental caries is caused by acids from biofilms. pH-sensitive nanoparticle carriers could achieve improved targeted effectiveness. The objectives of this study were to develop novel mesoporous silica nanoparticles carrying nanosilver and chlorhexidine (nMS-nAg-Chx), and investigate the inhibition of biofilms as well as the modulation of biofilm to suppress acidogenic and promote benign species for the first time.
METHODS
nMS-nAg was synthesized via a modified sol-gel method. Carboxylate group functionalized nMS-nAg (COOH-nMS-nAg) was prepared and Chx was added via electrostatic interaction. Minimal inhibitory concentration (MIC), inhibition zone, and growth curves were evaluated. Streptococcus mutans (S. mutans), Streptococcus gordonii (S. gordonii), and Streptococcus sanguinis (S. sanguinis) formed multispecies biofilms. Metabolic activity, biofilm lactic acid, exopolysaccharides (EPS), and TaqMan real-time polymerase chain reaction (RT-PCR) were tested. Biofilm structures and biomass were observed by scanning electron microscopy (SEM) and live/dead bacteria staining.
RESULTS
nMS-nAg-Chx possessed pH-responsive properties, where Chx release increased at lower pH. nMS-nAg-Chx showed good biocompatibility. nMS-nAg-Chx exhibited a strong antibacterial function, reducing biofilm metabolic activity and lactic acid as compared to control (p < 0.05, n = 6). Moreso, biofilm biomass was dramatically suppressed in nMS-nAg-Chx groups. In control group, there was an increasing trend of S. mutans proportion in the multispecies biofilm, with S. mutans reaching 89.1% at 72 h. In sharp contrast, in nMS-nAg-Chx group of 25 μg/mL, the ratio of S. mutans dropped to 43.7% and the proportion of S. gordonii and S. sanguinis increased from 19.8% and 10.9 to 69.8% and 56.3%, correspondingly.
CONCLUSION
pH-sensitive nMS-nAg-Chx had potent antibacterial effects and modulated biofilm toward a non-cariogenic tendency, decreasing the cariogenic species nearly halved and increasing the benign species approximately twofold. nMS-nAg-Chx is promising for applications in mouth rinse and endodontic irrigants, and as fillers in resins to prevent caries.
Topics: Humans; Chlorhexidine; Dental Caries; Silicon Dioxide; Anti-Bacterial Agents; Streptococcus mutans; Nanoparticles; Lactic Acid; Biofilms; Hydrogen-Ion Concentration; Silver
PubMed: 37951751
DOI: 10.1016/j.dental.2023.11.006 -
The Journal of Biological Chemistry Dec 2023Bacteria utilize quorum sensing (QS) to coordinate many group behaviors. As such, QS has attracted significant attention as a potential mean to attenuate bacterial...
Bacteria utilize quorum sensing (QS) to coordinate many group behaviors. As such, QS has attracted significant attention as a potential mean to attenuate bacterial infectivity without introducing selective pressure for resistance development. Streptococcus mitis, a human commensal, acts as a genetic diversity reservoir for Streptococcus pneumoniae, a prevalent human pathogen. S. mitis possesses a typical comABCDE competence regulon QS circuitry; however, the competence-stimulating peptide (CSP) responsible for QS activation and the regulatory role of the competence regulon QS circuitry in S. mitis are yet to be explored. We set out to delineate the competence regulon QS circuitry in S. mitis, including confirming the identity of the native CSP signal, evaluating the molecular mechanism that governs CSP interactions with histidine kinase receptor ComD leading to ComD activation, and defining the regulatory roles of the competence regulon QS circuitry in initiating various S. mitis phenotypes. Our analysis revealed important structure-activity relationship insights of the CSP signal and facilitated the development of novel CSP-based QS modulators. Our analysis also revealed the involvement of the competence regulon in modulating competence development and biofilm formation. Furthermore, our analysis revealed that the native S. mitis CSP signal can modulate QS response in S. pneumoniae. Capitalizing on this crosstalk, we developed a multispecies QS modulator that activates both the pneumococcus ComD receptors and the S. mitis ComD-2 receptor with high potencies. The novel scaffolds identified herein can be utilized to evaluate the effects temporal QS modulation has on S. mitis as it inhabits its natural niche.
Topics: Humans; Bacterial Proteins; Histidine Kinase; Peptides; Phenotype; Quorum Sensing; Regulon; Streptococcus mitis; Streptococcus pneumoniae; Structure-Activity Relationship; Species Specificity
PubMed: 37951305
DOI: 10.1016/j.jbc.2023.105448 -
Polish Archives of Internal Medicine Dec 2023
Topics: Humans; Streptococcus sanguis; Streptococcal Infections; Endocarditis, Bacterial; Heart; Heart Defects, Congenital
PubMed: 37943186
DOI: 10.20452/pamw.16601 -
Case Reports in Gastroenterology 2023Extracolonic manifestations of have been rarely reported. We herein report a case of a 60-year-old immunocompetent man presenting with fever, nausea, abdominal pain,...
Extracolonic manifestations of have been rarely reported. We herein report a case of a 60-year-old immunocompetent man presenting with fever, nausea, abdominal pain, and loose stools for 2 weeks. Triple-phase liver computed tomography demonstrated pyogenic liver abscesses and portal pylephlebitis. Blood cultures grew and , and liver abscess cultures grew , , and the viridans group . Antibiotics coverage was selected to direct at all identified organisms. This demonstrates an unusual case of bacteremia in a patient with polymicrobial pyogenic liver abscesses and pylephlebitis.
PubMed: 37928967
DOI: 10.1159/000531892 -
Genes Sep 2023Persisters are a small fraction of growth-arrested phenotypic variants that can survive lethal concentrations of antibiotics but are able to resume growth once...
Persisters are a small fraction of growth-arrested phenotypic variants that can survive lethal concentrations of antibiotics but are able to resume growth once antibiotics are stopped. Their formation can be a stochastic process or one triggered by environmental cues. In the human pathogen , the canonical peptide-based quorum-sensing system is an inducible DNA repair system that is pivotal for bacterial survival. Previous work has shown that the CSP-signaling peptide is a stress-signaling alarmone that promotes the formation of stress-induced persisters. In this study, we exposed to the CSP pheromone to mimic DNA damage conditions and isolated the antibiotic persisters by treating the cultures with ofloxacin. A transcriptome analysis was then performed to evaluate the differential gene expression between the normal stationary-phase cells and the persisters. RNA sequencing revealed that triggered persistence was associated with the upregulation of genes related to several stress defense mechanisms, notably, multidrug efflux pumps, the arginine deaminase pathway, and the Opu/Opc system. In addition, we showed that inactivation of the VicK kinase of the YycFG essential two-component regulatory system abolished the formation of triggered persisters via the CSP pheromone. These data contribute to the understanding of the triggered persistence phenotype and may suggest new therapeutic strategies for treating persistent streptococcal infections.
Topics: Humans; Quorum Sensing; Streptococcus mutans; Bacterial Proteins; Anti-Bacterial Agents; Gene Expression Profiling; Peptides; Pheromones; Defense Mechanisms
PubMed: 37895236
DOI: 10.3390/genes14101887 -
International Journal of Molecular... Oct 2023This work unveils the idea that the cariogenic status of the oral cavity (the presence of active caries lesions) can be predicted via a lineshape analysis of the...
Changes in Dental Biofilm Proteins' Secondary Structure in Groups of People with Different Cariogenic Situations in the Oral Cavity and Using Medications by Means of Synchrotron FTIR-Microspectroscopy.
This work unveils the idea that the cariogenic status of the oral cavity (the presence of active caries lesions) can be predicted via a lineshape analysis of the infrared spectral signatures of the secondary structure of proteins in dental biofilms. These spectral signatures that work as natural markers also show strong sensitivity to the application in patients of a so-called modulator-a medicinal agent (a pelleted mineral complex with calcium glycerophosphate). For the first time, according to our knowledge, in terms of deconvolution of the complete spectral profile of the amide I and amide II bands, significant intra- and intergroup differences were determined in the secondary structure of proteins in the dental biofilm of patients with a healthy oral cavity and with a carious pathology. This allowed to conduct a mathematical assessment of the spectral shifts in proteins' secondary structure in connection with the cariogenic situation in the oral cavity and with an external modulation. It was shown that only for the component in the amide profile of the biofilm, a statistically significant ( < 0.05) change in its percentage weight (composition) was registered in a cariogenic situation (presence of active caries lesions). Note that no significant differences were detected in a normal situation (control) and in the presence of a carious pathology before and after the application of the modulator. The change in the frequency and percentage weight of in the spectra of dental biofilms proved to be the result of the presence of cariogenic mutans streptococci in the film as well as of the products of their metabolism-glucan polymers. We foresee that the results presented here can inherently provide the basis for the infrared spectral diagnosis of changes (shifts) in the oral microbiome driven by the development of the carious process in the oral cavity as well as for the choice of optimal therapeutic treatments of caries based on microbiome-directed prevention measures.
Topics: Humans; Spectroscopy, Fourier Transform Infrared; Synchrotrons; Streptococcus mutans; Biofilms; Mouth; Amides; Dental Caries
PubMed: 37895003
DOI: 10.3390/ijms242015324 -
International Journal of Molecular... Oct 2023We conducted a meta-analysis and systematic review to investigate the efficacy of chitosan-containing chewing gums, and to test their inhibitory effects on . The... (Meta-Analysis)
Meta-Analysis Review
We conducted a meta-analysis and systematic review to investigate the efficacy of chitosan-containing chewing gums, and to test their inhibitory effects on . The systematic search was performed in three databases (Cochrane Library, EMBASE, and PubMed) and included English-language randomized-controlled trials to compare the efficacy of chitosan in reducing the number of . To assess the certainty of evidence, the GRADE tool was used. Mean differences were calculated with a 95% confidence interval for one outcome: bacterial counts in CFU/mL. The protocol of the study was registered on PROSPERO, registration number CRD42022365006. Articles were downloaded ( = 6758) from EMBASE ( = 2255), PubMed ( = 1516), and Cochrane ( = 2987). After the selection process, a total of four articles were included in the qualitative synthesis and three in the quantitative synthesis. Our results show that chitosan reduced the number of bacteria. The difference in mean quantity was -4.68 × 10. The interval of the random-effects model was [-2.15 × 10; 1.21 × 10] and the prediction interval was [1.03 × 10; 9.40 × 10]. The I2 value was 98% ( = 0.35), which indicates a high degree of heterogeneity. Chitosan has some antibacterial effects when used as a component of chewing gum, but further studies are needed. It can be a promising antimicrobial agent for prevention.
Topics: Humans; Streptococcus mutans; Saliva; Chitosan; Anti-Infective Agents; Anti-Bacterial Agents; Chewing Gum; Dental Caries
PubMed: 37894948
DOI: 10.3390/ijms242015270 -
Medicina (Kaunas, Lithuania) Oct 2023: The oral cavity is inhabited by pathogenic bacteria, whose growth can be inhibited by synthetic oral drugs, including antibiotics and other chemical compounds. Natural...
: The oral cavity is inhabited by pathogenic bacteria, whose growth can be inhibited by synthetic oral drugs, including antibiotics and other chemical compounds. Natural antimicrobial substances that elicit fewer negative side effects may serve as alternatives to synthetic agents for long-term use. Thus, the aim of this study was to evaluate the effects of edible mixed herbal extracts on the growth of oral pathogenic bacteria. : The yield of each herbal extract was as follows: 5% Briq (STB), 10.94% (MP), 5.47% Seem (AS), and 10.66% (GU). The herbal extracts used included 0.5 mg/mL STB, 1.5 mg/mL MP, 1.5 mg/mL AS, and 2.0 mg/mL GU. Antimicrobial tests, morphological analyses (using scanning electron microscopy), microbial surface hydrophobicity measurements, and oral malodor reduction tests were performed using each extract. Statistical analyses were performed with IBM SPSS (version 24), using paired -tests. : The mixed herbal extracts significantly inhibited the growth of and compared to the control ( < 0.001). Scanning electron microscopy results further revealed altered cellular morphology in the groups treated with the mixed herbal extracts. Additionally, the hydrophobicity assay results showed that the mixed herbal extracts reduced the oral adhesion capacities of bacteria ( < 0.001). Administration of the mixed herbal extracts also reduced the levels of volatile sulfur compounds, the main contributors to oral malodor ( < 0.001). : Edible mixed herbal extracts can effectively eliminate oral pathogens and may be useful for improving oral health. The herbal extracts used were effective against all species of oral pathogens studied in this report.
Topics: Humans; Plant Extracts; Halitosis; Streptococcus mutans; Anti-Infective Agents; Anti-Bacterial Agents
PubMed: 37893489
DOI: 10.3390/medicina59101771