title: Current methods for capsular typing of Streptococcus pneumoniae.
abstract: Streptococcus pneumoniae is a major respiratory tract pathogen causing pneumococcal disease mainly in children aged less than five years and in the elderly. Ninety-eight different capsular types (serotypes) of pneumococci have been reported, but pneumococcal conjugate vaccines (PCV) include polysaccharide antigens against only 7, 10 or 13 serotypes. It is therefore important to track the emergence of serotypes due to the clonal expansion of non-vaccine serotypes. Increased numbers of carried and disease-causing pneumococci are now being analysed as part of the post-PCV implementation surveillance studies and hence rapid, accurate and cost-effective typing methods are important. Here we describe serotyping methods published prior to 10th November 2014 for pneumococcal capsule typing. Sixteen methods were identified; six were based on serological tests using immunological properties of the capsular epitopes, eight were semi-automated molecular tests, and one describes the identification of capsular type directly from whole genome data, which also allows for further intra and inter-genome analyses. There was no single method that could be recommended for all pneumococcal capsular typing applications. Although the Quellung reaction is still considered to be the gold-standard, laboratories should take into account the number of pneumococcal isolates and the type of samples to be used for testing, the time frame for the results and the resources available in order to select the most appropriate method. Most likely, a combination of phenotypic and genotypic methods would be optimal to monitor and evaluate the impact of pneumococcal conjugate vaccines and to provide information for future vaccine formulations.
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK; Infectious Diseases, Genome Institute of Singapore, 138672, Singapore.
authors.forename: Elita
authors.initials: E
authors.lastname: Jauneikaite
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: Anna S
authors.initials: AS
authors.lastname: Tocheva
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK; NIHR Southampton Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK.
authors.forename: Johanna M C
authors.initials: JM
authors.lastname: Jefferies
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Gladstone
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK; NIHR Southampton Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK; NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK.
authors.forename: Saul N
authors.initials: SN
authors.lastname: Faust
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: Myron
authors.initials: M
authors.lastname: Christodoulides
authors.affiliation: Infectious Diseases, Genome Institute of Singapore, 138672, Singapore; London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
authors.forename: Martin L
authors.initials: ML
authors.lastname: Hibberd
authors.affiliation: Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton SO16 6YD, UK; NIHR Southampton Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK. Electronic address: S.C.Clarke@Southampton.ac.uk.
authors.forename: Stuart C
authors.initials: SC
authors.lastname: Clarke
mesh_terms: D016667:Bacterial Capsules / Q000145:classification* / Q000235:genetics / Q000276:immunology; D016680:Genome, Bacterial; D005838:Genotype; D010641:Phenotype; D022242:Pneumococcal Vaccines; D065288:Serogroup; D012703:Serotyping / Q000379:methods*; D013296:Streptococcus pneumoniae / Q000145:classification*; D013997:Time Factors; D018074:Vaccines, Conjugate
chemical_list: D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Capsular polysaccharide; Serotyping; Streptococcus pneumoniae