title: Real-time PCR-based serotyping of Streptococcus agalactiae.
abstract: Group B Streptococcus (GBS) is an encapsulated, gram-positive pathogen that is an important cause of neonatal invasive infections, including sepsis and meningitis. There are ten known GBS serotypes based on distinct capsule compositions (Ia, Ib, II-IX), and current candidate capsular polysaccharide conjugate vaccines target only a subset of these. Serotyping of GBS isolates is important for understanding local epidemiology and for monitoring for serotype replacement or capsular switching. However, serotyping generally requires either latex agglutination, multiplex PCR with analysis of band sizes, or analysis of whole genome sequences-all techniques that are either expensive or not widely available. Here we report the development of a robust real-time PCR assay for determining GBS serotypes. Using both a diverse reference set of strains encompassing all ten serotypes and a collection of clinical isolates, we demonstrate concordance between real-time PCR serotyping and latex agglutination. We propose that real-time PCR serotyping represents an attractive alternative to current serotyping methods and may allow for improved acquisition of GBS serotype data.
authors.affiliation: College of Physicians &Surgeons, Columbia University, New York, NY USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Breeding
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY USA.
authors.forename: Bhavana
authors.initials: B
authors.lastname: Ragipani
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY USA.
authors.forename: Kun-Uk David
authors.initials: KD
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Malik
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY USA.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Randis
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY USA.|Department of Microbiology, New York University School of Medicine, New York, NY USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Ratner
mesh_terms: D004247:DNA / Q000235:genetics; D006384:Hemagglutination; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012703:Serotyping; D013292:Streptococcus agalactiae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D013698:Templates, Genetic
chemical_list: D004247:DNA