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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 -
European Journal of Clinical... Apr 2014In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the... (Review)
Review
In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?
Topics: Biofilms; Dental Caries; Humans; Streptococcus mutans; Tooth; Virulence
PubMed: 24154653
DOI: 10.1007/s10096-013-1993-7 -
Microbiology Spectrum Jul 2019is the best characterized species among the lactococci, and among the most consumed food-fermenting bacteria worldwide. Thanks to their importance in industrialized... (Review)
Review
is the best characterized species among the lactococci, and among the most consumed food-fermenting bacteria worldwide. Thanks to their importance in industrialized food production, lactococci are among the lead bacteria understood for fundamental metabolic pathways that dictate growth and survival properties. Interestingly, lactococci belong to the Streptococcaceae family, which includes food, commensal and virulent species. As basic metabolic pathways (e.g., respiration, metal homeostasis, nucleotide metabolism) are now understood to underlie virulence, processes elucidated in lactococci could be important for understanding pathogen fitness and synergy between bacteria. This chapter highlights major findings in lactococci and related bacteria, and covers five themes: distinguishing features of lactococci, metabolic capacities including the less known respiration metabolism in Streptococcaceae, factors and pathways modulating stress response and fitness, interbacterial dialogue metabolites, and novel applications in health and biotechnology.
Topics: Bacterial Proteins; Fermentation; Lactococcus lactis; Metabolic Networks and Pathways
PubMed: 31298208
DOI: 10.1128/microbiolspec.GPP3-0035-2018 -
Scandinavian Journal of Immunology Sep 2015Streptococcal bacteria are a versatile group of gram-positive bacteria capable of infecting several host organisms, including humans and fish. Streptococcal species are... (Review)
Review
Streptococcal bacteria are a versatile group of gram-positive bacteria capable of infecting several host organisms, including humans and fish. Streptococcal species are common colonizers of the human respiratory and gastrointestinal tract, but they also cause some of the most common life-threatening, invasive infections in humans and aquaculture. With its unique characteristics and efficient tools for genetic and imaging applications, the zebrafish (Danio rerio) has emerged as a powerful vertebrate model for infectious diseases. Several zebrafish models introduced so far have shown that zebrafish are suitable models for both zoonotic and human-specific infections. Recently, several zebrafish models mimicking human streptococcal infections have also been developed. These models show great potential in providing novel information about the pathogenic mechanisms and host responses associated with human streptococcal infections. Here, we review the zebrafish infection models for the most relevant streptococcal species: the human-specific Streptococcus pneumoniae and Streptococcus pyogenes, and the zoonotic Streptococcus iniae and Streptococcus agalactiae. The recent success and the future potential of these models for the study of host-pathogen interactions in streptococcal infections are also discussed.
Topics: Animals; Disease Models, Animal; Humans; Streptococcal Infections; Streptococcus; Streptococcus agalactiae; Streptococcus pneumoniae; Streptococcus pyogenes; Zebrafish
PubMed: 26095827
DOI: 10.1111/sji.12320 -
Revista Chilena de Infectologia :... Jun 2015Granulicatella spp. is a bacteria of the oral cavity, belonging to the nutritionally variant group streptococci, and has been identified in 5% of all bacterial...
Granulicatella spp. is a bacteria of the oral cavity, belonging to the nutritionally variant group streptococci, and has been identified in 5% of all bacterial endocarditis. It's an important etiologic species in endocarditis, particularly in the setting of negative blood cultures. Granulicatella is a non-mobile, non- spore forming organism that is both catalase and oxidase negative. The treatment for Granulicatella, is the same for Enterococcus according to the American and European guidelines, however resistance to this treatment has been reported.
Topics: Streptococcus
PubMed: 26230446
DOI: 10.4067/S0716-10182015000400017 -
Frontiers in Cellular and Infection... 2024Streptococci are primary colonizers of the oral cavity where they are ubiquitously present and an integral part of the commensal oral biofilm microflora. The role oral... (Review)
Review
Streptococci are primary colonizers of the oral cavity where they are ubiquitously present and an integral part of the commensal oral biofilm microflora. The role oral streptococci play in the interaction with the host is ambivalent. On the one hand, they function as gatekeepers of homeostasis and are a prerequisite for the maintenance of oral health - they shape the oral microbiota, modulate the immune system to enable bacterial survival, and antagonize pathogenic species. On the other hand, also recognized pathogens, such as oral and , which trigger the onset of dental caries belong to the genus . In the context of periodontitis, oral streptococci as excellent initial biofilm formers have an accessory function, enabling late biofilm colonizers to inhabit gingival pockets and cause disease. The pathogenic potential of oral streptococci fully unfolds when their dissemination into the bloodstream occurs; streptococcal infection can cause extra-oral diseases, such as infective endocarditis and hemorrhagic stroke. In this review, the taxonomic diversity of oral streptococci, their role and prevalence in the oral cavity and their contribution to oral health and disease will be discussed, focusing on the virulence factors these species employ for interactions at the host interface.
Topics: Humans; Dental Caries; Streptococcus; Streptococcus mutans; Streptococcus sobrinus; Mouth; Biofilms
PubMed: 38456080
DOI: 10.3389/fcimb.2024.1357631 -
Current Issues in Molecular Biology 2019Streptococci are a group of Gram-positive bacteria belonging to the family Streptococcaceae, which are responsible of multiple diseases. Some of these species can cause... (Review)
Review
Streptococci are a group of Gram-positive bacteria belonging to the family Streptococcaceae, which are responsible of multiple diseases. Some of these species can cause invasive infection that may result in life-threatening illness. Moreover, antibiotic-resistant bacteria are considerably increasing, thus imposing a global consideration. One of the main causes of this resistance is the horizontal gene transfer (HGT), associated to gene transfer agents including transposons, integrons, plasmids and bacteriophages. These agents, which are called mobile genetic elements (MGEs), encode proteins able to mediate DNA movements. This review briefly describes MGEs in streptococci, focusing on their structure and properties related to HGT and antibiotic resistance.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Conjugation, Genetic; Drug Resistance, Multiple, Bacterial; Gene Expression Regulation, Bacterial; Gene Transfer, Horizontal; Genome, Bacterial; Host-Pathogen Interactions; Humans; Interspersed Repetitive Sequences; Streptococcal Infections; Streptococcus pneumoniae; Streptococcus pyogenes; Transformation, Bacterial; Virulence
PubMed: 31166171
DOI: 10.21775/cimb.032.123 -
Revista Chilena de Infectologia :... Oct 2012
Topics: Streptococcus suis
PubMed: 23282499
DOI: 10.4067/S0716-10182012000600012 -
Infection, Genetics and Evolution :... Jul 2015The genus Streptococcus contains 104 recognized species, many of which are associated with human or animal hosts. A globally prevalent human pathogen in this group is... (Review)
Review
The genus Streptococcus contains 104 recognized species, many of which are associated with human or animal hosts. A globally prevalent human pathogen in this group is Streptococcus pneumoniae (the pneumococcus). While being a common resident of the upper respiratory tract, it is also a major cause of otitis media, pneumonia, bacteremia and meningitis, accounting for a high burden of morbidity and mortality worldwide. Recent findings demonstrate the importance of recombination and selection in driving the population dynamics and evolution of different pneumococcal lineages, allowing them to successfully evade the impacts of selective pressures such as vaccination and antibiotic treatment. We highlight the ability of pneumococci to respond to these pressures through processes including serotype replacement, capsular switching and horizontal gene transfer (HGT) of antibiotic resistance genes. The challenge in controlling this pathogen also lies in the exceptional genetic and phenotypic variation among different pneumococcal lineages, particularly in terms of their pathogenicity and resistance to current therapeutic strategies. The widespread use of pneumococcal conjugate vaccines, which target only a small subset of the more than 90 pneumococcal serotypes, provides us with a unique opportunity to elucidate how the processes of selection and recombination interact to generate a remarkable level of plasticity and heterogeneity in the pneumococcal genome. These processes also play an important role in the emergence and spread of multi-resistant strains, which continues to pose a challenge in disease control and/or eradication. The application of population of genomic approaches at different spatial and temporal scales will help improve strategies to control this global pathogen, and potentially other pathogenic streptococci.
Topics: Animals; Bacteriophages; Biodiversity; DNA Transposable Elements; Evolution, Molecular; Gene Transfer, Horizontal; Genetic Variation; Genome, Bacterial; Humans; Pneumococcal Infections; Selection, Genetic; Streptococcus; Vaccination
PubMed: 25461843
DOI: 10.1016/j.meegid.2014.11.007 -
Microbiology and Immunology Nov 2021The genus Streptococcus infects a broad range of hosts, including humans. Some species, such as S. pyogenes, S. agalactiae, S. pneumoniae, and S. mutans, are recognized... (Review)
Review
The genus Streptococcus infects a broad range of hosts, including humans. Some species, such as S. pyogenes, S. agalactiae, S. pneumoniae, and S. mutans, are recognized as the major human pathogens, and their pathogenicity toward humans has been investigated. However, many of other streptococcal species have been recognized as opportunistic pathogens in humans, and their clinical importance has been underestimated. In our previous study, the Anginosus group streptococci (AGS) and Mitis group streptococci (MGS) showed clear β-hemolysis on blood agar, and the factors responsible for the hemolysis were homologs of two types of β-hemolysins, cholesterol-dependent cytolysin (CDC) and streptolysin S (SLS). In contrast to the regular β-hemolysins produced by streptococci (typical CDCs and SLSs), genetically, structurally, and functionally atypical β-hemolysins have been observed in AGS and MGS. These atypical β-hemolysins are thought to affect and contribute to the pathogenic potential of opportunistic streptococci mainly inhabiting the human oral cavity. In this review, we introduce the diverse characteristics of β-hemolysin produced by opportunistic streptococci, focusing on the species/strains belonging to AGS and MGS, and discuss their pathogenic potential.
Topics: Hemolysin Proteins; Hemolysis; Humans; Streptococcal Infections; Streptococcus pneumoniae; Streptococcus pyogenes
PubMed: 34591320
DOI: 10.1111/1348-0421.12936