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Taxonomy of oral streptococci


One of the problems that plague investigation contribution oral streptococci for plaque formation was that decisions taxonomic relationship between different types observed. Indeed, many routine diagnostic laboratories continue to lump all oral streptococci together under a descriptive term is? viridans streptococci`, which refers to the planting of reaction, or hemolysis produced on blood agar. This classification is clearly limited, as not all are oral streptococci-hemolytic, and hemolytic species such as S. pneumoniae are not normal inhabitants of the oral cavity. More importantly, there is a vast heterogeneity physiological properties within the group, so we could foresee various properties of virulence. many attempts have therefore been made over the years to develop schemes for identifying streptococci to the level of species, laboratory tests. These have been largely based on biochemical properties such as the ability to use different carbohydrate substrates.

Serotyping schemes have also played a role in defining taxonomic boundaries, but none of the approaches on the basis of bacterial phenotype (sothat is, the properties of bacteria display in laboratory culture) were fully satisfactory.

It was only with the use of molecular methods based on genotype bacteria that all variety of types of streptococci was recognized, first using DNA-DNA hybridization experiments and later sequencing of genes of ribosomal RNA. By the middle of 1980-ies, was officially recognized that a group of bacteria that were previously described as S. mutans, in fact, contains a number of different species that had different properties in common, but, nevertheless, had distinct features. This together referred to as the? mutans group " or Mutans streptococci (MS). As a result, having different properties, different species have different nodes and benefits of different environments. It also became clear that some species that were the subject of animal studies (C. cricetus, S. rattus) were rarely, if ever, that in the human body. Taxonomy mutans streptococci group now seems to be durable, with General agreement by type definition. Before anyone sighs with relief, it should be noted that even the concept of the?species bacteria was thrown in the dispute further developments in our understanding of the bacterial population structures, caused by the new genome sequencing approaches. For a long time we were familiar with the idea that all members of the species such as S. mutans were the same, based on our understanding of binary fission, so that all the descendants of dividing bacteria are identical, and thus a homogeneous clone. It now seems that it is very far from the truth. The problem is well illustrated mitis group that contains the greatest number of named species oral streptococci. Data from rRNA sequencing shows that S. pneumoniae is also in this group, although its habitat is naso-pharynx, and not the mouth. S. pneumoniae is closely linked C. mitis and S. oralis, and currently, there are numerous reports of the presence of a wide exchange of genetic information between species.

For the first time the message appeared to penicillin-binding protein, when genes resistant to penicillin isolates of S. pneumoniae, it was demonstrated that has a mosaic structure, with segments clearly identical genes S. oralis. Synanthropic oral streptococci, thus, offer a pool of genetic material that can undergo gene shuffling with important pathogen and lead to the emergence of resistant strains. Other genes, show mosaic; thus, there is reason to think that there may be extensive and mixing genetic traits, mitis group. This raises the question of whether the currently defined types can be divided clear boundaries, or they form a continuum with many mosaic isolates displaying a mixture of properties is now regarded as a characteristic of the individual species. The presence of heterogeneity and Gene exchange within populations of bacteria has important implications for certain preventive strategies aimed distinctive features.One difficulties that have plagued the investigation contribution oral streptococci for plaque formation was that decisions taxonomic relationship between different types observed. Indeed, many routine diagnostic laboratories continue to lump all oral streptococci together under a descriptive term is? viridans streptococci`, which refers to the planting of reaction, or hemolysis produced on blood agar. This classification is clearly limited, as not all are oral streptococci-hemolytic, and hemolytic species such as S. pneumoniae are not normal inhabitants of the oral cavity. More importantly, there is a vast heterogeneity physiological properties within the group, so we could foresee various properties of virulence. many attempts have therefore been made over the years to develop schemes for identifying streptococci to the level of species, laboratory tests. These have been largely based on biochemical properties such as the ability to use different carbohydrate substrates.

Serotyping schemes have also played a role in defining taxonomic boundaries, but none of the approaches on the basis of bacterial phenotype (i.e. properties of bacteria display in laboratory culture) were fully satisfactory. It was only with the use of molecular methods based on genotype bacteria that all variety of types of streptococci was recognized, first using DNA-DNA hybridization experiments and later sequencing of genes of ribosomal RNA. By the middle of 1980-ies, was officially recognized that a group of bacteria that were previously described as S. mutans, in fact, contains a number of different species that had different properties in common, but, nevertheless, had distinct features. This together referred to as the? mutans group " or Mutans streptococci (MS). As a result, having different properties, different species have different nodes and benefits of different environments. It also became clear that some species that were the subject of animal studies (C. cricetus, S. rattus) were rarely, if ever, that in the human body.

Taxonomy mutans streptococci group now seems to be durable, with General agreement by type definition. Before anyone sighs with relief, it should be noted that even the concept of the?species bacteria was thrown in the dispute further developments in our understanding of the bacterial population structures, caused by the new genome sequencing approaches. For a long time we were familiar with the idea that all members of the species such as S. mutans were the same, based on our understanding of binary fission, so that all the descendants of dividing bacteria are identical, and thus a homogeneous clone. It now seems that it is very far from the truth. The problem is well illustrated mitis group that contains the greatest number of named species oral streptococci. Data from rRNA sequencing shows that S. pneumoniae is also in this group, although its habitat is naso-pharynx, and not the mouth. S. pneumoniae is closely linked C. mitis and S. oralis, and currently, there are numerous reports of the presence of a wide exchange of genetic information between species.

For the first time the message appeared to penicillin-binding protein, when genes resistant to penicillin isolates of S. pneumoniae, it was demonstrated that has a mosaic structure, with segments clearly identical genes S. oralis. Synanthropic oral streptococci, thus, offer a pool of genetic material that can undergo gene shuffling with important pathogen and lead to the emergence of resistant strains. Other genes, show mosaic; thus, there is reason to think that there may be extensive and mixing genetic traits, mitis group. This raises the question of whether the currently defined types can be divided clear boundaries, or they form a continuum with many mosaic isolates displaying a mixture of properties is now regarded as a characteristic of the individual species. The presence of heterogeneity and Gene exchange within populations of bacteria has important implications for certain preventive strategies aimed distinctive features...

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