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Adhesion determinants of the Streptococcus species.

Moschioni M, Pansegrau W, Barocchi MA - Microb Biotechnol (2009)

Bottom Line: Phylogenetic analyses based on 16S rRNA sequences of the streptococcal species reveal a clustering pattern, reflecting, with a few exceptions, their pathogenic potential and ecological preferences.Bacterial adhesins recognize and bind cell surface molecules and extracellular matrix components through specific domains that for certain adhesin families have been well defined and found conserved across the streptococcal species.In this review, we present the different streptococcal adhesin families categorized on the basis of their adhesive properties and structural characteristics, and, when available, we focus the attention on conserved functional domains.

View Article: PubMed Central - PubMed

Affiliation: Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena, Italy.

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Phylogeny of Streptococcus species based on 16S rRNA conservation. Phylogenetic and molecular evolutionary analyses were conducted using MEGA version 4 (Tamura et al., 2004). Main groups are indicated by coloured areas. Streptococcal species in which adhesins were described are marked by filled boxes. Those species for which the complete genome is available are marked with red or yellow half circles. Red indicates that the sequence can be retrieved from NCBI, yellow indicates that the sequence is available either from The Sanger Institute or from the J.C. Venter Institute.
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f1: Phylogeny of Streptococcus species based on 16S rRNA conservation. Phylogenetic and molecular evolutionary analyses were conducted using MEGA version 4 (Tamura et al., 2004). Main groups are indicated by coloured areas. Streptococcal species in which adhesins were described are marked by filled boxes. Those species for which the complete genome is available are marked with red or yellow half circles. Red indicates that the sequence can be retrieved from NCBI, yellow indicates that the sequence is available either from The Sanger Institute or from the J.C. Venter Institute.

Mentions: The nomenclature of Streptococcus species is rather complex as it is not only based on the species names but, for historical reasons, designations are used that are based on haemolysis type or serological grouping. In particular, Lancefield typing based on specific antisera against ‘group‐specific’ carbohydrate or lipoteichoic acid (Group D) antigens has been and is widely used to classify beta‐haemolytic streptococci. As an example it turned out, however, that S. pyogenes, for which often the terminus GAS (group A Streptococcus) is used as a synonym, is not the only Streptococcus that may possess the group A antigen because also S. anginosus or S. dysgalactiae ssp. equisimilis may carry the A antigen. On the other hand, a given streptococcal species may have several diverse types of Lancefield antigen e.g. Streptococcus dysgalactiae ssp. equisimilis may be a carrier of A, C, G or L antigens (Facklam, 2002). In the last decades phylogenetic typing based on 16S rRNA (Fig. 1) has helped the accurate identification of bacterial isolates and the discovery of novel bacteria in clinical microbiology laboratories to form a clearer picture of streptococcal species relationships. In Fig. 1 we identified in the genus Streptococcus five major clusters: S. mitis, S. mutans, S. salivarius (viridians streptococci), S. agalactiae and S. pyogenes (pyogenic group). This analysis reveals a clustering pattern reflecting the pathogenic potential and ecological preferences of the streptococcal species (Kawamura et al., 1995). One exception is the mitis group, which contains one of the leading pathogens, S. pneumoniae, along with other species that are prototype commensals of the upper respiratory tract (such as S. mitis, S. oralis or S. infantis). Recent works (Kilian et al., 2008; Bishop et al., 2009) propose the use of concatenated sequences of conserved housekeeping genes in addition to the analysis of presence/absence of virulence‐specific genes to better assign newly discovered atypical isolates, identify eventual new species, discriminate between species that are really close in terms of 16S rRNA sequences, and define in this way a standard taxonomic procedure for the genus Streptococcus.


Adhesion determinants of the Streptococcus species.

Moschioni M, Pansegrau W, Barocchi MA - Microb Biotechnol (2009)

Phylogeny of Streptococcus species based on 16S rRNA conservation. Phylogenetic and molecular evolutionary analyses were conducted using MEGA version 4 (Tamura et al., 2004). Main groups are indicated by coloured areas. Streptococcal species in which adhesins were described are marked by filled boxes. Those species for which the complete genome is available are marked with red or yellow half circles. Red indicates that the sequence can be retrieved from NCBI, yellow indicates that the sequence is available either from The Sanger Institute or from the J.C. Venter Institute.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815805&req=5

f1: Phylogeny of Streptococcus species based on 16S rRNA conservation. Phylogenetic and molecular evolutionary analyses were conducted using MEGA version 4 (Tamura et al., 2004). Main groups are indicated by coloured areas. Streptococcal species in which adhesins were described are marked by filled boxes. Those species for which the complete genome is available are marked with red or yellow half circles. Red indicates that the sequence can be retrieved from NCBI, yellow indicates that the sequence is available either from The Sanger Institute or from the J.C. Venter Institute.
Mentions: The nomenclature of Streptococcus species is rather complex as it is not only based on the species names but, for historical reasons, designations are used that are based on haemolysis type or serological grouping. In particular, Lancefield typing based on specific antisera against ‘group‐specific’ carbohydrate or lipoteichoic acid (Group D) antigens has been and is widely used to classify beta‐haemolytic streptococci. As an example it turned out, however, that S. pyogenes, for which often the terminus GAS (group A Streptococcus) is used as a synonym, is not the only Streptococcus that may possess the group A antigen because also S. anginosus or S. dysgalactiae ssp. equisimilis may carry the A antigen. On the other hand, a given streptococcal species may have several diverse types of Lancefield antigen e.g. Streptococcus dysgalactiae ssp. equisimilis may be a carrier of A, C, G or L antigens (Facklam, 2002). In the last decades phylogenetic typing based on 16S rRNA (Fig. 1) has helped the accurate identification of bacterial isolates and the discovery of novel bacteria in clinical microbiology laboratories to form a clearer picture of streptococcal species relationships. In Fig. 1 we identified in the genus Streptococcus five major clusters: S. mitis, S. mutans, S. salivarius (viridians streptococci), S. agalactiae and S. pyogenes (pyogenic group). This analysis reveals a clustering pattern reflecting the pathogenic potential and ecological preferences of the streptococcal species (Kawamura et al., 1995). One exception is the mitis group, which contains one of the leading pathogens, S. pneumoniae, along with other species that are prototype commensals of the upper respiratory tract (such as S. mitis, S. oralis or S. infantis). Recent works (Kilian et al., 2008; Bishop et al., 2009) propose the use of concatenated sequences of conserved housekeeping genes in addition to the analysis of presence/absence of virulence‐specific genes to better assign newly discovered atypical isolates, identify eventual new species, discriminate between species that are really close in terms of 16S rRNA sequences, and define in this way a standard taxonomic procedure for the genus Streptococcus.

Bottom Line: Phylogenetic analyses based on 16S rRNA sequences of the streptococcal species reveal a clustering pattern, reflecting, with a few exceptions, their pathogenic potential and ecological preferences.Bacterial adhesins recognize and bind cell surface molecules and extracellular matrix components through specific domains that for certain adhesin families have been well defined and found conserved across the streptococcal species.In this review, we present the different streptococcal adhesin families categorized on the basis of their adhesive properties and structural characteristics, and, when available, we focus the attention on conserved functional domains.

View Article: PubMed Central - PubMed

Affiliation: Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena, Italy.

Show MeSH
Related in: MedlinePlus