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Updated: May 7, 2026
04:25
Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
Serotyping of Streptococcus pneumoniae based on capsular genes polymorphisms.
Frédéric Raymond1, Nancy Boucher, Robin Allary
1Centre de Recherche en Infectiologie and Département de Microbiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada.
Plos One
|October 3, 2013
Summary
A new PCR-based microarray assay accurately tracks Streptococcus pneumoniae serotypes, crucial for monitoring vaccine effectiveness and understanding serotype replacement in populations.
Area of Science:
- Microbiology
- Vaccinology
- Molecular Diagnostics
Background:
- Serotype epidemiology of Streptococcus pneumoniae is critical for evaluating the impact of conjugate vaccines.
- Serotype replacement is a significant concern following the introduction of new vaccines.
- Accurate and rapid serotyping methods are needed to track epidemiological changes.
Purpose of the Study:
- To develop and validate a novel PCR-based automated microarray assay for Streptococcus pneumoniae serotyping.
- To assess the assay's performance on cultured isolates and clinical specimens.
- To evaluate the assay's utility in tracking serotype prevalence post-vaccine introduction.
Main Methods:
- Multiplex PCR amplification of autolysin, pneumolysin, and capsular operon genes.
- Tagged fluorescent primer extension targeting serotype-specific polymorphisms.
- Hybridization to a microarray followed by expert system analysis for serotype identification.
Main Results:
- The assay correctly serotyped 75.9% of 166 cultured S. pneumoniae samples across 63 serotypes.
- Identification of 22 serotypes and subgroup assignment for 24 others based on 12 polymorphisms.
- Successful serotyping of 89% of pneumolysin-positive clinical specimens without prior culturing.
Conclusions:
- The developed automated microarray assay provides a reliable method for Streptococcus pneumoniae serotyping.
- The assay is suitable for clinical testing and does not require sample culturing.
- This tool will aid in monitoring serotype prevalence shifts after new conjugate vaccine implementation.
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