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Type: Journal article
Title: Recombinational exchanges at the capsular polysaccharide biosynthetic locus lead to frequent serotype changes among natural isolates of Streptococcus pneumoniae.
Author: Coffey, T.
Enright, M.
Daniels, M.
Morona, J.
Morona, R.
Hryniewicz, W.
Paton, J.
Spratt, B.
Citation: Molecular Microbiology, 1998; 27(1):73-83
Issue Date: 1998
ISSN: 0950-382X
Abstract: Serotype 19F variants of the major Spanish multiresistant serotype 23F clone of Streptococcus pneumoniae have been proposed to have arisen by recombinational exchanges at the capsular biosynthetic locus. Members of the Spanish multiresistant serotype 23F clone and the serotype 19F variants were confirmed to be essentially identical in overall genotype, as they were indistinguishable by REP-PCR, and had identical sequences at three polymorphic housekeeping genes. Eight serotype 19F variants were studied and all had large recombinational replacements at the capsular biosynthetic locus. In all cases, one of the recombinational cross-over points appeared to be upstream of dexB, which flanks one end of the capsular locus, and in six of the variants the other cross-over point was downstream of aliA, which flanks the other end of the locus. In two strains a recombinational cross-over point between the introduced serotype 19F capsular region and that of the Spanish serotype 23F clone could be clearly identified, within cpsN in one strain and within cpsM in the other. The differences in the recombinational junctions and sequence polymorphisms within the introduced capsular genes, suggested that the eight serotype 19F variants emerged on at least four separate occasions. Changes in capsular type by recombination may therefore be relatively frequent in pneumococci and this has implications for the long-term efficacy of conjugate pneumococcal vaccines that will protect against only a limited number of serotypes.
Keywords: Streptococcus pneumoniae
Polysaccharides, Bacterial
DNA, Bacterial
DNA Fingerprinting
Polymerase Chain Reaction
Sequence Analysis, DNA
Drug Resistance, Multiple
Recombination, Genetic
Crossing Over, Genetic
Base Sequence
Repetitive Sequences, Nucleic Acid
Sequence Homology, Nucleic Acid
Polymorphism, Restriction Fragment Length
Molecular Sequence Data
DOI: 10.1046/j.1365-2958.1998.00658.x
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Appears in Collections:Aurora harvest 2
Microbiology and Immunology publications

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