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Frontiers in Cellular and Infection... 2023Dental biofilms are highly assembled microbial communities surrounded by an extracellular matrix, which protects the resident microbes. The microbes, including commensal... (Review)
Review
Dental biofilms are highly assembled microbial communities surrounded by an extracellular matrix, which protects the resident microbes. The microbes, including commensal bacteria and opportunistic pathogens, coexist with each other to maintain relative balance under healthy conditions. However, under hostile conditions such as sugar intake and poor oral care, biofilms can generate excessive acids. Prolonged low pH in biofilm increases proportions of acidogenic and aciduric microbes, which breaks the ecological equilibrium and finally causes dental caries. Given the complexity of oral microenvironment, controlling the acidic biofilms using antimicrobials that are activated at low pH could be a desirable approach to control dental caries. Therefore, recent researches have focused on designing novel kinds of pH-activated strategies, including pH-responsive antimicrobial agents and pH-sensitive drug delivery systems. These agents exert antibacterial properties only under low pH conditions, so they are able to disrupt acidic biofilms without breaking the neutral microenvironment and biodiversity in the mouth. The mechanisms of low pH activation are mainly based on protonation and deprotonation reactions, acids labile linkages, and H-triggered reactive oxygen species production. This review summarized pH-activated antibiofilm strategies to control dental caries, concentrating on their effect, mechanisms of action, and biocompatibility, as well as the limitation of current research and the prospects for future study.
Topics: Humans; Dental Caries; Streptococcus sanguis; Streptococcus mutans; Biofilms; Anti-Infective Agents; Hydrogen-Ion Concentration
PubMed: 36949812
DOI: 10.3389/fcimb.2023.1130506 -
Journal of Clinical Microbiology Dec 2019
PubMed: 31757884
DOI: 10.1128/JCM.01525-18 -
Oman Medical Journal Mar 2023Eye infections can be caused by several microorganisms and the most common causative bacterial agents are staphylococci, streptococci, and This study aimed to estimate... (Review)
Review
OBJECTIVES
Eye infections can be caused by several microorganisms and the most common causative bacterial agents are staphylococci, streptococci, and This study aimed to estimate the prevalence of viridans group streptococci, and as the cause of ocular infections in Iran.
METHODS
We conducted a systematic search on the studies published by Iranian authors from January 2000 to December 2020 in Web of Science, PubMed, Scopus, and Embase. Eligible studies were selected according to the defined inclusion/exclusion criteria. Statistical heterogeneity between and within groups was estimated by the Q-statistic and I index. The funnel plots, Duval and Tweedie trim, and fill methods were obtained to evaluate the evidence of publication bias.
RESULTS
Twenty-seven studies were included in this review. According to the meta-analysis results, the prevalence of was 19.1% (95% CI: 12.5-28.1). It was estimated 6.9% (95% CI: 4.4-10.6), 6.7% (95% CI: 4.6-9.6), and 3.3% (95% CI: 1.8-5.8) for and viridans streptococci, respectively.
CONCLUSIONS
. is the prevalent bacterial agents responsible for eye-associated infections in Iran.
PubMed: 37132006
DOI: 10.5001/omj.2023.22 -
PloS One 2020The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia...
The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia polycrystals: TZP). CpTi and yttria-stabilized TZP disks with a mirror-polished surface were used as specimens. The arithmetic mean surface roughness (Ra and Sa) and the surface wettability of the experimental specimens were measured. For analyzing the outermost layer of the experimental specimens, X-ray photoelectron spectroscopy (XPS) analysis was performed. Streptococcus sanguinis, S. gordonii, S. oralis, and S. mutans were used as streptococcal bacterial strains. These bacterial cultures were grown for 24 h on CpTi and TZP. The number of bacterial adhesions was estimated using an ATP-bioluminescent assay, and scanning electron microscope (SEM) observation of the adhered bacterial specimens was performed. No significant differences in surface roughness or wettability were found between CpTi and TZP. In XPS analyses, outermost layer of CpTi included Ti0 and Ti4+, and outermost layer of TZP included Zr4+. In the cell adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis to TZP were significantly lower than those to CpTi (p < 0.05); however, significant difference was not observed for S. mutans among the specimens. The adherence to CpTi and TZP of S. mutans was significantly lower than that of S. sanguinis, S. gordonii, and S. oralis. These results were confirmed by SEM. S. sanguinis, S. gordonii, and S. oralis adhered less to TZP than to CpTi, but the adherence of S. mutans was similar to both surfaces. S. mutans was less adherent compare with the other streptococci tested in those specimens.
Topics: Bacterial Adhesion; Materials Testing; Microscopy, Electron, Scanning; Photoelectron Spectroscopy; Streptococcus sanguis; Surface Properties; Titanium; Yttrium; Zirconium
PubMed: 32579584
DOI: 10.1371/journal.pone.0234524 -
Microbiology Spectrum Aug 2023Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes are widely recognized as bacterial adaptive immune systems against...
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes are widely recognized as bacterial adaptive immune systems against invading viruses and bacteriophages. The oral pathogen Streptococcus mutans encodes two CRISPR-Cas loci (CRISPR1-Cas and CRISPR2-Cas), and their expression under environmental conditions is still under investigation. In this study, we investigated the transcriptional regulation of operons by CcpA and CodY, two global regulators that contribute to carbohydrate and (p)ppGpp metabolism. The possible promoter regions for operons and the binding sites for CcpA and CodY in the promoter regions of both CRISPR-Cas loci were predicted using computational algorithms. We found that CcpA could directly bind to the upstream region of both operons, and detected an allosteric interaction of CodY within the same region. The binding sequences of the two regulators were identified through footprinting analysis. Our results showed that the promoter activity of CRISPR1-Cas was enhanced under fructose-rich conditions, while deletion of the gene led to reduced activity of the CRISPR2-Cas promoter under the same conditions. Additionally, deletion of the CRISPR systems resulted in a significant decrease in fructose uptake ability compared to the parental strain. Interestingly, the accumulation of guanosine tetraphosphate (ppGpp) was reduced in the presence of mupirocin, which induces a stringent response, in the CRISPR1-Cas-deleted (ΔCR1) and both CRISPR-Cas-deleted (ΔCRD) mutant strains. Furthermore, the promoter activity of both CRISPRs was enhanced in response to oxidative or membrane stress, while the CRISPR1 promoter activity was reduced under low-pH conditions. Collectively, our findings demonstrate that the transcription of the CRISPR-Cas system is directly regulated by the binding of CcpA and CodY. These regulatory actions play a crucial role in modulating glycolytic processes and exerting effective CRISPR-mediated immunity in response to nutrient availability and environmental cues. An effective immune system has evolved not only in eukaryotic organisms but also in microorganisms, enabling them to rapidly detect and neutralize foreign invaders in the environment. Specifically, the CRISPR-Cas system in bacterial cells is established through a complex and sophisticated regulatory mechanism involving specific factors. In this study, we demonstrate that the expression of two CRISPR systems in S. mutans can be controlled by two global regulators, CcpA and CodY, which play critical roles in carbohydrate metabolism and amino acid biosynthesis. Importantly, our results show that the expression of the CRISPR-Cas system in S. mutans influences (p)ppGpp production during the stringent response, which is a gene expression regulatory response that aids in environmental stress adaptation. This transcriptional regulation by these regulators enables a CRISPR-mediated immune response in a host environment with limited availability of carbon sources or amino acids, while ensuring efficient carbon flux and energy expenditure to support multiple metabolic processes.
Topics: CRISPR-Cas Systems; Streptococcus mutans; Guanosine Pentaphosphate; Promoter Regions, Genetic; Fructose; Bacterial Proteins
PubMed: 37367300
DOI: 10.1128/spectrum.01826-23 -
Scientific Reports Jun 2021Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been...
Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been well done. In this study, we isolated 125 S. mutans strains from volunteers and determined their whole genome sequence. Based on the genome analysis, the distribution of each bacteriocin gene (mutacins I-IV, K8 and Smb) was investigated. We found 17, 5, and 2 strains showing 100% matches with mutacin I, mutacin II and mutacin III, respectively. Five mutacin III-positive strains had 2 mismatches compared to mature mutacin III. In 67 mutacin IV-positive strains, 38 strains showed 100% match with mutacin IV, while 29 strains showed some variations. In 23 mutacin K8- and 32 mutacin Smb-positive strains, all except one mutacin K8-positive strain showed 100% match with the mature peptides. Among 125 strains, 84 (65.1%), 26 (20.2%), and 5 (3.9%) strains were positive for one, two and three bacteriocin genes, respectively. Then, the antibacterial activity against oral streptococci and other oral bacterial species was investigated by using bacteriocin gene single-positive strains. Each bacteriocin gene-positive strain showed a different pattern of antibacterial activity. These results speculate that individual S. mutans strains may affect the bacterial composition of dental plaques.
Topics: Amino Acid Sequence; Anti-Bacterial Agents; Antibiosis; Bacteriocins; Gene Expression Regulation, Bacterial; Humans; Microbial Sensitivity Tests; Mutation; Promoter Regions, Genetic; Regulatory Sequences, Nucleic Acid; Streptococcus mutans
PubMed: 34155274
DOI: 10.1038/s41598-021-92370-1 -
Sichuan Da Xue Xue Bao. Yi Xue Ban =... Mar 2022The prevalence of dental caries remains high, posing a major burden on the public health of the global society. Microorganisms are the main cause of dental caries, among... (Review)
Review
The prevalence of dental caries remains high, posing a major burden on the public health of the global society. Microorganisms are the main cause of dental caries, among which ( ) is one of the most widely recognized cariogenic bacteria. In recent years, the progress in research technology enabled the academic circle to conduct more in-depth research into caries-inducing at the DNA, RNA and protein levels, and to gain thereby a new understanding of the surface structure and extracellular matrix composition of . In this paper, we summarized recent findings on the cariogenic mechanism of in order to help reveal more targets and potential approaches for the future development of caries prevention agents that target , and to promote the development of dental caries prevention campaign.
Topics: Dental Caries; Humans; Streptococcus mutans
PubMed: 35332719
DOI: 10.12182/20220360508 -
Infection and Immunity Mar 2024Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis,...
Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis, periodontal disease, and oral cancer. Specifically, is associated with esophageal, gastric, and pharyngeal cancers, while is linked to oral cancer. However, no study has investigated the mechanistic links between these species and cancer-related inflammatory responses. As an initial step, we probed the innate immune response triggered by and in RAW264.7 macrophages. These bacteria exerted time- and dose-dependent effects on macrophage morphology without affecting cell viability. Compared with untreated macrophages, macrophages infected with exhibited a robust proinflammatory response characterized by significantly increased levels of inflammatory cytokines and mediators, including TNF, IL-6, IL-1β, NOS2, and COX2, accompanied by enhanced NF-κB activation. In contrast, -infected macrophages failed to elicit a robust inflammatory response. Seahorse Xfe96 analysis revealed an increased extracellular acidification rate in macrophages infected with compared with . At the 24-h time point, the presence of led to reduced extracellular itaconate, while triggered increased itaconate levels, highlighting distinct metabolic profiles in macrophages during infection in contrast to aconitate decarboxylase expression observed at the 6-h time point. This initial investigation highlights how and , two Gram-positive bacteria from the same genus, can prompt distinct immune responses and metabolic shifts in macrophages during infection.IMPORTANCEThe surge in head and neck cancer cases among individuals devoid of typical risk factors such as Human Papilloma Virus (HPV) infection and tobacco and alcohol use sparks an argumentative discussion around the emerging role of oral microbiota as a novel risk factor in oral squamous cell carcinoma (OSCC). While substantial research has dissected the gut microbiome's influence on physiology, the oral microbiome, notably oral streptococci, has been underappreciated during mucosal immunopathogenesis. , a viridans streptococci group, has been linked to abscess formation and an elevated presence in esophageal cancer and OSCC. The current study aims to probe the innate immune response to compared with the early colonizer as an important first step toward understanding the impact of distinct oral species on the host immune response, which is an understudied determinant of OSCC development and progression.
Topics: Humans; Streptococcus anginosus; Carcinoma, Squamous Cell; Mouth Neoplasms; Dental Caries; Streptococcus; Macrophages; Succinates
PubMed: 38289109
DOI: 10.1128/iai.00536-23 -
The ISME Journal Jul 2023During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these...
During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these interactions, we used information gained from recent biogeographical investigations demonstrating an association of corynebacteria with streptococci. We previously reported that Streptococcus sanguinis and Corynebacterium durum have a close relationship through the production of membrane vesicle and fatty acids leading to S. sanguinis chain elongation and overall increased fitness supporting their commensal state. Here we present the molecular mechanisms of this interspecies interaction. Coculture experiments for transcriptomic analysis identified several differentially expressed genes in S. sanguinis. Due to its connection to fatty acid synthesis, we focused on the glycerol-operon. We further explored the differentially expressed type IV pili genes due to their connection to motility and biofilm adhesion. Gene inactivation of the glycerol kinase glpK had a profound impact on the ability of S. sanguinis to metabolize C. durum secreted glycerol and impaired chain elongation important for their interaction. Investigations on the effect of type IV pili revealed a reduction of S. sanguinis twitching motility in the presence of C. durum, which was caused by a decrease in type IV pili abundance on the surface of S. sanguinis as determined by SEM. In conclusion, we identified that the ability to metabolize C. durum produced glycerol is crucial for the interaction of C. durum and S. sanguinis. Reduced twitching motility could lead to a closer interaction of both species, supporting niche development in the oral cavity and potentially shaping symbiotic health-associated biofilm communities.
Topics: Glycerol; Streptococcus; Streptococcus sanguis; Biofilms; Symbiosis; Streptococcus mutans
PubMed: 37169870
DOI: 10.1038/s41396-023-01426-9 -
Virulence Dec 2023is a ubiquitous commensal species of the oral cavity commonly involved as an opportunistic pathogen in cardiovascular infections. In this study, we investigated the...
is a ubiquitous commensal species of the oral cavity commonly involved as an opportunistic pathogen in cardiovascular infections. In this study, we investigated the functions of endopeptidase O (PepO) and a C3-degrading protease (CppA) in the systemic virulence of . Isogenic mutants of and obtained in strain SK36 showed increased susceptibility to C3b deposition and to opsonophagocytosis by human polymorphonuclear neutrophils (PMN). These mutants differ, however, in their profiles of binding to serum amyloid P component (SAP) and C1q, whereas both showed reduced interaction with C4b-binding protein (C4BP) and/or factor H (FH) regulators as compared to SK36. The two mutants showed defects in persistence in human blood, serum-mediated invasion of HCAEC endothelial cells, and virulence in a infection model. The transcriptional activities of and , assessed by RT-qPCR in nine wild-type strains, further indicated strain-specific profiles of / expression. Moreover, non-conserved amino acid substitutions were detected among the strains, mostly in CppA. Phylogenetic comparisons with homologues of streptococcal species of the oral and oropharyngeal sites suggested that PepO and CppA have independent ancestralities. Thus, this study showed that PepO and CppA are complement evasion proteins expressed by in a strain-specific manner, which are required for multiple functions associated with cardiovascular virulence.
Topics: Humans; Streptococcus sanguis; Virulence; Endothelial Cells; Phylogeny; Complement System Proteins; Bacterial Proteins
PubMed: 37563831
DOI: 10.1080/21505594.2023.2239519