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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 -
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 -
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 -
Virulence 2015Streptococcus tigurinus is a novel species of viridans streptococci, shown to cause severe invasive infections such as infective endocarditis, spondylodiscitis and... (Review)
Review
Streptococcus tigurinus is a novel species of viridans streptococci, shown to cause severe invasive infections such as infective endocarditis, spondylodiscitis and meningitis. S. tigurinus belongs to the Streptococcus mitis group and is most closely related to Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, Streptococcus pseudopneumoniae and Streptococcus infantis. The presence of S. tigurinus in the human oral cavity has been documented, including in patients with periodontal disease. This review addresses the available scientific knowledge on S. tigurinus and its association with closely related streptococci, and discusses its putative involvement in common oral infections. While there is as yet no strong evidence on the involvement of S. tigurinus with oral infections, its presence in the oral cavity and its association with endocarditis warrants special attention for a link between oral and systemic infection.
Topics: DNA, Bacterial; Endocarditis, Bacterial; Humans; Microbiota; Mouth; Periodontal Diseases; Periodontitis; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Streptococcal Infections; Streptococcus; Streptococcus mitis
PubMed: 25483862
DOI: 10.4161/21505594.2014.970472 -
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 -
Polish Journal of Microbiology 2010Beta-hemolytic, pyogenic streptococci are classified according to type of major surface antigen into A (Streptococcus pyogenes), B (Streptococcus agalactiae), C... (Review)
Review
Beta-hemolytic, pyogenic streptococci are classified according to type of major surface antigen into A (Streptococcus pyogenes), B (Streptococcus agalactiae), C (multiple species including Streptococcus dysagalactiae) and G (multiple species including Streptococcus canis) Lancefield groups. Group A Streptococcus causes each year hundreds of thousands deaths globally as a result of infections and post-infectional sequelae. An increasing number of severe, invasive infections is caused by selected, specialized pathogenic clones. Within the last 50 years, an increasing number of human infections caused by groups B, C and G Streptococcus (GBS, GCS, GGS) has been observed worldwide. GBS was first identified as animal pathogen but the spectrum of diseases caused by GBS quickly shifted to human infections. Groups C and G Streptococcus are still regarded mostly as animal pathogens, however, an increased number of severe infections caused by these groups is observed. The increasing number of human infections caused worldwide by GCS/GGS can be a sign of similar development from animal to human pathogen as observed in case of GBS and this group will gain much more clinical interest in the future.The situation in Poland regarding invasive infections caused by pyogenic streptococci is underestimated.
Topics: Animals; Communicable Diseases, Emerging; Humans; Poland; Streptococcal Infections; Streptococcus; Streptococcus agalactiae; Streptococcus pyogenes; Virulence Factors; Zoonoses
PubMed: 21466038
DOI: No ID Found -
Current Drug Targets 2019It has been proposed that GAS may form biofilms. Biofilms are microbial communities that aggregate on a surface, and exist within a self-produced matrix of extracellular... (Review)
Review
BACKGROUND
It has been proposed that GAS may form biofilms. Biofilms are microbial communities that aggregate on a surface, and exist within a self-produced matrix of extracellular polymeric substances. Biofilms offer bacteria an increased survival advantage, in which bacteria persist, and resist host immunity and antimicrobial treatment. The biofilm phenotype has long been recognized as a virulence mechanism for many Gram-positive and Gram-negative bacteria, however very little is known about the role of biofilms in GAS pathogenesis.
OBJECTIVE
This review provides an overview of the current knowledge of biofilms in GAS pathogenesis. This review assesses the evidence of GAS biofilm formation, the role of GAS virulence factors in GAS biofilm formation, modelling GAS biofilms, and discusses the polymicrobial nature of biofilms in the oropharynx in relation to GAS.
CONCLUSION
Further study is needed to improve the current understanding of GAS as both a monospecies biofilm, and as a member of a polymicrobial biofilm. Improved modelling of GAS biofilm formation in settings closely mimicking in vivo conditions will ensure that biofilms generated in the lab closely reflect those occurring during clinical infection.
Topics: Anti-Bacterial Agents; Biofilms; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Models, Biological; Oropharynx; Streptococcus; Virulence Factors
PubMed: 30947646
DOI: 10.2174/1389450120666190405095712 -
Molecular Microbiology Jun 2007Competence for natural genetic transformation in Streptococcus pneumoniae is controlled by the extracellular concentration of the competence-stimulating peptide (CSP),... (Review)
Review
Competence for natural genetic transformation in Streptococcus pneumoniae is controlled by the extracellular concentration of the competence-stimulating peptide (CSP), an exported peptide pheromone. Upon entering the competent state, pneumococci start transcribing a number of CSP-responsive genes, termed the early and late competence (com) genes. Some of the proteins encoded by these com genes are absolutely required for DNA uptake and transformation, but most of them are dispensable. This finding indicates that the majority of CSP-regulated proteins in S. pneumoniae is involved in processes unrelated to natural genetic transformation. Recently, however, it became clear that the biological role of a few of the dispensable proteins might be linked to the transformation process. Although these proteins are not needed for transformation per se, they constitute a killing mechanism that could be used by competent cells to acquire DNA from non-competent pneumococci. This mechanism, termed fratricide, has so far only been described for pneumococci. In this manuscript, we review evidence that suggests the conservation of fratricide as well as the independent evolution of its genetic control and of its effectors in several species of the genus Streptococcus, and discuss its possible biological significance in relation to natural transformation.
Topics: Bacterial Proteins; Bacteriocins; Bacteriolysis; Gene Expression Regulation, Bacterial; Streptococcus; Transformation, Bacterial
PubMed: 17555432
DOI: 10.1111/j.1365-2958.2007.05757.x -
Biometals : An International Journal on... Jun 2015Streptococcal solute-binding proteins (SBPs) associated with ATP-binding cassette transporters gained widespread attention first as ostensible adhesins, next as... (Review)
Review
Streptococcal solute-binding proteins (SBPs) associated with ATP-binding cassette transporters gained widespread attention first as ostensible adhesins, next as virulence determinants, and finally as metal ion transporters. In this mini-review, we will examine our current understanding of the cellular roles of these proteins, their contribution to metal ion homeostasis, and their crucial involvement in mediating streptococcal virulence. There are now more than 35 studies that have collected structural, biochemical and/or physiological data on the functions of SBPs across a broad range of bacteria. This offers a wealth of data to clarify the formerly puzzling and contentious findings regarding the metal specificity amongst this group of essential bacterial transporters. In particular we will focus on recent findings related to biological roles for manganese in streptococci. These advances will inform efforts aimed at exploiting the importance of manganese and manganese acquisition for the design of new approaches to combat serious streptococcal diseases.
Topics: Animals; Bacterial Proteins; Humans; Manganese; Streptococcus; Virulence
PubMed: 25652937
DOI: 10.1007/s10534-015-9826-z -
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