title: Sequential multiplex PCR assay for determining capsular serotypes of colonizing S. pneumoniae.
abstract: BACKGROUND
  Asymptomatic nasopharyngeal carriage represents an important biological marker for monitoring pneumococcal serotype distribution and evaluating vaccine effects. Serotype determination by conventional method (Quellung reaction) is technically and financially challenging. On the contrary, PCR-based serotyping represents a simple, economic and promising alternative method.
  
  
  METHODS
  We designed a novel multiplex PCR assay for specific detection of the 30 classical colonizing S. pneumoniae serogroups/types. This multiplex assay is composed of 7 consecutive PCR reactions and was validated on a large and recent collection of Streptococcus pneumoniae isolated during a prospective study conducted in Belgium at the time of PCV7 adoption.
  
  
  RESULTS
  The multiplex PCR assay allowed the typing of more than 94% of the isolates of a collection of pneumococci isolated from Belgian preschool attendees (n = 332). Seventy-five percent of the isolates were typed after 3 subsequent PCR reactions. Results were in agreement with the Quellung identification.
  
  
  CONCLUSIONS
  Our novel multiplex assay is an accurate and reliable method which can be used in place of the conventional method for S. pneumoniae carriage studies.
authors.affiliation: Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, Bruxelles, Belgium. sajourda@ulb.ac.be
authors.forename: Sarah
authors.initials: S
authors.lastname: Jourdain
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Drèze
authors.forename: Jozef
authors.initials: J
authors.lastname: Vandeven
authors.forename: Jan
authors.initials: J
authors.lastname: Verhaegen
authors.forename: Laurence
authors.initials: L
authors.lastname: Van Melderen
authors.forename: Pierre R
authors.initials: PR
authors.lastname: Smeesters
mesh_terms: D016667:Bacterial Capsules / Q000032:analysis / Q000235:genetics*; D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D009305:Nasopharynx / Q000382:microbiology; D011008:Pneumococcal Infections / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000191:economics / Q000379:methods*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification