-
Microbiology Spectrum Oct 2018Bacteria belonging to the genus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of... (Review)
Review
Bacteria belonging to the genus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of the oral microbiota. In this article, we discuss the different oral environments inhabited by streptococci and the species that occupy each niche. Special attention is given to the taxonomy of , because this genus is now divided into eight distinct groups, and oral species are found in six of them. Oral streptococci produce an arsenal of adhesive molecules that allow them to efficiently colonize different tissues in the mouth. Also, they have a remarkable ability to metabolize carbohydrates via fermentation, thereby generating acids as byproducts. Excessive acidification of the oral environment by aciduric species such as is directly associated with the development of dental caries. However, less acid-tolerant species such as and produce large amounts of alkali, displaying an important role in the acid-base physiology of the oral cavity. Another important characteristic of certain oral streptococci is their ability to generate hydrogen peroxide that can inhibit the growth of . Thus, oral streptococci can also be beneficial to the host by producing molecules that are inhibitory to pathogenic species. Lastly, commensal and pathogenic streptococci residing in the oral cavity can eventually gain access to the bloodstream and cause systemic infections such as infective endocarditis.
Topics: Carbohydrate Metabolism; Dental Caries; Endocarditis; Fermentation; Humans; Hydrogen Peroxide; Metagenomics; Microbiota; Mouth; Phylogeny; Streptococcus; Streptococcus gordonii; Streptococcus mutans; Streptococcus salivarius
PubMed: 30338752
DOI: 10.1128/microbiolspec.GPP3-0042-2018 -
Periodontology 2000 Jun 2022Oral and esophageal squamous cell carcinomas harbor a diverse microbiome that differs compositionally from precancerous and healthy tissues. Though causality is yet to... (Review)
Review
Oral and esophageal squamous cell carcinomas harbor a diverse microbiome that differs compositionally from precancerous and healthy tissues. Though causality is yet to be definitively established, emerging trends implicate periodontal pathogens such as Porphyromonas gingivalis as associated with the cancerous state. Moreover, infection with P. gingivalis correlates with a poor prognosis, and P. gingivalis is oncopathogenic in animal models. Mechanistically, properties of P. gingivalis that have been established in vitro and could promote tumor development include induction of a dysbiotic inflammatory microenvironment, inhibition of apoptosis, increased cell proliferation, enhanced angiogenesis, activation of epithelial-to-mesenchymal transition, and production of carcinogenic metabolites. The microbial community context is also relevant to oncopathogenicity, and consortia of P. gingivalis and Fusobacterium nucleatum are synergistically pathogenic in oral cancer models in vivo. In contrast, oral streptococci, such as Streptococcus gordonii, can antagonize protumorigenic epithelial cell phenotypes induced by P. gingivalis, indicating functionally specialized roles for bacteria in oncogenic communities. Consistent with the notion of the bacterial community constituting the etiologic unit, metatranscriptomic data indicate that functional, rather than compositional, properties of the tumor-associated communities have more relevance to cancer development. A consistent association of P. gingivalis with oral and orodigestive carcinoma could have diagnostic potential for early detection of these conditions that have a high incidence and low survival rates.
Topics: Animals; Carcinoma, Squamous Cell; Fusobacterium nucleatum; Humans; Microbiota; Mouth Neoplasms; Porphyromonas gingivalis; Tumor Microenvironment
PubMed: 35244980
DOI: 10.1111/prd.12425 -
Microorganisms Nov 2020, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that... (Review)
Review
, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that can cause local or systemic diseases, such as apical periodontitis and infective endocarditis. , an early colonizer, easily attaches to host tissues, including tooth surfaces and heart valves, forming biofilms. penetrates into root canals and blood streams, subsequently interacting with various host immune and non-immune cells. The cell wall components of which include lipoteichoic acids, lipoproteins, serine-rich repeat adhesins, peptidoglycans, and cell wall proteins, are recognizable by individual host receptors. They are involved in virulence and immunoregulatory processes causing host inflammatory responses. Therefore, cell wall components act as virulence factors that often progressively develop diseases through overwhelming host responses. This review provides an overview of and how its cell wall components could contribute to the pathogenesis and development of therapeutic strategies.
PubMed: 33255499
DOI: 10.3390/microorganisms8121852 -
Applied and Environmental Microbiology Oct 2021Cell-cell adhesion between oral bacteria plays a key role in the development of polymicrobial communities such as dental plaque. Oral streptococci such as Streptococcus...
Cell-cell adhesion between oral bacteria plays a key role in the development of polymicrobial communities such as dental plaque. Oral streptococci such as Streptococcus gordonii and Streptococcus oralis are important early colonizers of dental plaque and bind to a wide range of different oral microorganisms, forming multispecies clumps or "coaggregates." S. gordonii actively responds to coaggregation by regulating gene expression. To further understand these responses, we assessed gene regulation in S. gordonii and S. oralis following coaggregation in 25% human saliva. Coaggregates were formed by mixing, and after 30 min, RNA was extracted for dual transcriptome sequencing (RNA-Seq) analysis. In S. oralis, 18 genes (6 upregulated and 12 downregulated) were regulated by coaggregation. Significantly downregulated genes encoded functions such as amino acid and antibiotic biosynthesis, ribosome, and central carbon metabolism. In total, 28 genes were differentially regulated in Streptococcus gordonii (25 upregulated and 3 downregulated). Many genes associated with transporters and a two-component (NisK/SpaK) regulatory system were upregulated following coaggregation. Our comparative analyses of S. gordoniiS. oralis with different previously published S. gordonii pairings (S. gordoniiFusobacterium nucleatum and S. gordoniiVeillonella parvula) suggest that the gene regulation is specific to each pairing, and responses do not appear to be conserved. This ability to distinguish between neighboring bacteria may be important for S. gordonii to adapt appropriately during the development of complex biofilms such as dental plaque. Dental plaque is responsible for two of the most prevalent diseases in humans, dental caries and periodontitis. Controlling the formation of dental plaque and preventing the transition from oral health to disease requires a detailed understanding of microbial colonization and biofilm development. Streptococci are among the most common colonizers of dental plaque. This study identifies key genes that are regulated when oral streptococci bind to one another, as they do in the early stages of dental plaque formation. We show that specific genes are regulated in two different oral streptococci following the formation of mixed-species aggregates. The specific responses of S. gordonii to coaggregation with S. oralis are different from those to coaggregation with other oral bacteria. Targeting the key genes that are upregulated during interspecies interactions may be a powerful approach to control the development of biofilm and maintain oral health.
Topics: Dental Plaque; Humans; RNA-Seq; Streptococcus gordonii; Streptococcus oralis; Transcriptome
PubMed: 34469191
DOI: 10.1128/AEM.01558-21 -
Applied and Environmental Microbiology Dec 2020Amino sugars, particularly glucosamine (GlcN) and -acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to...
Amino sugars, particularly glucosamine (GlcN) and -acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to the biofilms colonizing the human oral cavity. Evidence is emerging that these amino sugars provide ecological advantages to beneficial commensals over oral pathogens and pathobionts. Here, we performed transcriptome analysis on and growing in single-species or dual-species cultures with glucose, GlcN, or GlcNAc as the primary carbohydrate source. Compared to glucose, GlcN caused drastic transcriptomic shifts in each species of bacteria when it was cultured alone. Likewise, cocultivation in the presence of GlcN yielded transcriptomic profiles that were dramatically different from the single-species results from GlcN-grown cells. In contrast, GlcNAc elicited only minor changes in the transcriptome of either organism in single- and dual-species cultures. Interestingly, genes involved in pyruvate metabolism were among the most significantly affected by GlcN in both species, and these changes were consistent with measurements of pyruvate in culture supernatants. Differing from what was found in a previous report, growth of alone with GlcN inhibited the expression of multiple operons required for mutacin production. Cocultivation with consistently increased the expression of two manganese transporter operons ( and ) and decreased expression of mutacin genes in Conversely, appeared to be less affected by the presence of but did show increases in genes for biosynthetic processes in the cocultures. In conclusion, amino sugars profoundly alter the interactions between pathogenic and commensal streptococci by reprogramming central metabolism. Carbohydrate metabolism is central to the development of dental caries. A variety of sugars available to dental microorganisms influence the development of caries by affecting the physiology, ecology, and pathogenic potential of tooth biofilms. Using two well-characterized oral bacteria, one pathogen () and one commensal (), in an RNA deep-sequencing analysis, we studied the impact of two abundant amino sugars on bacterial gene expression and interspecies interactions. The results indicated large-scale remodeling of gene expression induced by GlcN in particular, affecting bacterial energy generation, acid production, protein synthesis, and release of antimicrobial molecules. Our study provides novel insights into how amino sugars modify bacterial behavior, information that will be valuable in the design of new technologies to detect and prevent oral infectious diseases.
Topics: Amino Sugars; Gene Expression; Gene Expression Profiling; Genes, Bacterial; Microbiota; Mouth; Streptococcus gordonii; Streptococcus mutans; Symbiosis
PubMed: 33097515
DOI: 10.1128/AEM.01459-20 -
Frontiers in Cellular and Infection... 2020is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent...
is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent species and affect polymicrobial pathogenesis. Previous studies have confirmed several adhering partner species of , including and . In this study, we discovered new intergeneric co-adherence between and the saliva isolate (GBS-SI101). Research shows that GBS typically colonizes the human gastrointestinal and vaginal tracts. It is responsible for adverse pregnancy outcomes and life-threatening infections in neonates and immunocompromised people. Our results revealed that GtfB and GtfC of , which contributed to extracellular polysaccharide synthesis, promoted coaggregation of with GBS-SI101. In addition, oral streptococci, including and , barely inhibited the growth of GBS-SI101. This study indicated that could help GBS integrate into the associated oral polymicrobial community and become a resident species in the oral cavity, increasing the risk of oral infections.
Topics: Biofilms; Dental Caries; Humans; Infant, Newborn; Streptococcus agalactiae; Streptococcus mutans; Streptococcus sanguis
PubMed: 32733820
DOI: 10.3389/fcimb.2020.00344 -
Tobacco Induced Diseases 2019Epidemiological studies have shown a close relationship between smoking and dental caries. Bacteria are one of the essential factors of caries formation. The imbalance... (Review)
Review
INTRODUCTION
Epidemiological studies have shown a close relationship between smoking and dental caries. Bacteria are one of the essential factors of caries formation. The imbalance of cariogenic bacteria and commensal bacteria in dental plaque results in higher production of acid that can corrode dental hard tissue. The aim of our review is to summarize the effect of smoking on caries-related bacteria.
METHODS
English articles available in Pubmed and ScienceDirect databases and published before December 2018 were searched. A variety of evidence was collected including not only the influence of cigarette products on bacteria strains but also their effect on bacterial composition in saliva and dental plaque . We particularly emphasize the mechanisms by which nicotine acts on oral bacteria.
RESULTS
The components of cigarettes promote the growth of cariogenic microorganisms. The mechanisms of how nicotine enhances and are described separately in detail. The commensal bacteria, , show less competitive capability in the presence of nicotine. Smoking influences saliva by lowering the buffer capability, altering its chemical agent and bacterial components, and therefore promotes the formation of a caries-susceptible environment.
CONCLUSIONS
Cigarette smoking and nicotine exposure promote the cariogenic activity of oral microorganisms and the formation of a caries-susceptible environment. This suggests that smokers should quit smoking, amongst other health reasons, also for their oral health.
PubMed: 31516475
DOI: 10.18332/tid/105913 -
Frontiers in Microbiology 2021Pathogenic streptococcal species are responsible for a broad spectrum of human diseases ranging from non-invasive and localized infections to more aggressive and... (Review)
Review
Pathogenic streptococcal species are responsible for a broad spectrum of human diseases ranging from non-invasive and localized infections to more aggressive and life-threatening diseases, which cause great economic losses worldwide. Streptococci possess a dozen two-component systems (TCSs) that play important roles in the response to different environmental changes and adjust the expression of multiple genes to successfully colonize and infect host cells. In this review, we discuss the progress in the study of a conserved TCS named CiaRH in pathogenic or opportunistic streptococci including , , , , , , and , focusing on the function and regulatory networks of CiaRH, which will provide a promising strategy for the exploration of novel antistreptococcal therapies. This review highlights the important role of CiaRH and provides an important basis for the development of antistreptococcal drugs and vaccines.
PubMed: 34335522
DOI: 10.3389/fmicb.2021.693858 -
Frontiers in Cellular and Infection... 2021Interspecies coaggregation promotes transcriptional changes in oral bacteria, affecting bacterial pathogenicity. () and () are common oral inhabitants. The present...
Interspecies coaggregation promotes transcriptional changes in oral bacteria, affecting bacterial pathogenicity. () and () are common oral inhabitants. The present study investigated the transcriptional profiling of and subsp. in response to the dual-species coaggregation using RNA-seq. Macrophages were infected with both species to explore the influence of bacterial coaggregation on both species' abilities to survive within macrophages and induce inflammatory responses. Results indicated that, after the 30-min dual-species coaggregation, 116 genes were significantly up-regulated, and 151 genes were significantly down-regulated in ; 97 genes were significantly down-regulated, and 114 genes were significantly up-regulated in subsp. . Multiple genes were involved in the biosynthesis and export of cell-wall proteins and carbohydrate metabolism. subsp. genes were mostly associated with translation and protein export. The coaggregation led to decreased expression levels of genes associated with lipopolysaccharide and peptidoglycan biosynthesis. Coaggregation between and subsp. significantly promoted both species' intracellular survival within macrophages and attenuated the production of pro-inflammatory cytokines IL-6 and IL-1β. Physical interactions between these two species promoted a symbiotic lifestyle and repressed macrophage's killing and pro-inflammatory responses.
Topics: Bacteria; Bacterial Adhesion; Fusobacterium nucleatum; Immunity; Macrophages; Streptococcus gordonii
PubMed: 35071038
DOI: 10.3389/fcimb.2021.783323 -
Journal of Dental Research Jan 2021is known to form polymicrobial biofilms with various spp., including mitis and mutans group streptococci. (mitis group) has been shown to bind avidly to hyphae via...
is known to form polymicrobial biofilms with various spp., including mitis and mutans group streptococci. (mitis group) has been shown to bind avidly to hyphae via direct cell-to-cell interaction, while the cariogenic pathogen (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between (or ) and in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that binding force to the surface is significantly higher than that of to the fungal surface (~2-fold). However, binding forces are dramatically enhanced when the cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated ), which vastly exceeds the forces between and. The enhanced binding affinity of to glucan-coated resulted in a larger structure during early biofilm initiation compared to biofilms. Ultimately, this resulted in dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of -streptococcal interaction whereby extracellular glucans may selectively favor binding interactions with during cariogenic biofilm development.
Topics: Biofilms; Candida albicans; Cell Communication; Streptococcus gordonii; Streptococcus mutans
PubMed: 32853527
DOI: 10.1177/0022034520950286