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Updated: Dec 24, 2025

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
Expanded sequential quadriplex real-time polymerase chain reaction (PCR) for identifying pneumococcal serotypes,
Srinivasan Velusamy1, Theresa Tran2, Thitipong Mongkolrattanothai3
1Respiratory Diseases Branch, Division of Bacterial Disease, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Abstract:
We expanded our current Centers for Disease Control and Prevention triplexed real-time polymerase chain reaction scheme identifying 11 individual serotypes and 10 serogroups to a quadriplex format identifying 34 individual serotypes and 13 small serogroups, 4 antibiotic resistance determinants, pilus targets, and penicillin susceptibility. Newly developed assays are specific for serotypes/serogroups, are sensitive (10 copies/reaction), and further discriminate larger serogroups into individual serotypes or smaller serogroups.

