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Current Molecular Medicine
ISSN (Print): 1566-5240
ISSN (Online): 1875-5666
VOLUME: 1
ISSUE: 4
DOI: 10.2174/1566524013363618      Price:  $58









Genetic Bases and Medical Relevance of Capsular Polysaccharide Biosynthesis in Pathogenic Streptococci

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Author(s): Daniel Llull, Rubens Lopez and Ernesto Garcia
Pages 475-491 (17)
Abstract:
Many streptococci are human and / or animal pathogens and the frequent cause of life-threatening diseases. Among various streptococcal virulence factors, capsular polysaccharides (CPs) are recognized as essential to prevent phagocytosis by macrophages and neutrophils. In the last decade, an impressive advance on the knowledge of the genetic bases underlying capsule formation has been achieved. The capsular gene cluster driving the formation of the CP of Streptococcus pyogenes and other hyaluronate-producing streptococci, represents one of the simplest cases of gene organization to synthesize a capsule. A more complex situation has been found in Streptococcus pneumoniae, Streptococcus agalactiae, Streptococcus suis, and other streptococci. On the whole, there exists a direct relationship between the structural and chemical complexity of the repeating unit of the polysaccharide and the number of genes found in the corresponding capsular locus. Streptococcal vaccines, either polysaccharide or conjugate, are currently being tested in clinical trials to overcome the rise of worldwide antibiotic resistance, although, for different reasons, none of these vaccines are expected to provide the required full coverage in a near future. This concern has prompted to explore alternative possibilities with an improved therapeutic potential against streptococcal diseases.
Keywords:
Capsular Polysaccharide, Streptococcus pneumoniae, Streptococcus agalactiae, Haemophilus influenzae, hyaluronate-associated protein (HAP), Streptococcus uberis, Signature-tagged mutagenesis
Affiliation:
Centro de InvestigacionesBiologicas, CSIC. Velazquez 144. 28006 Madrid, Spain