title: Comparison of PCR and serotyping of Group B Streptococcus in pregnant women: the Oslo GBS-study.
abstract: Streptococcus agalactiae (GBS) is a leading cause of invasive neonatal infection. Serotyping of GBS is important in following epidemiological trends and vaccine development. Capsular serotyping of GBS by latex agglutination has been the predominant typing method, but more recently capsular genotyping has been introduced as an alternative method. The purpose of this study was to compare the relative performance of these methods in a contemporary population of pregnant women. We typed isolates from an unselected population of 426 colonized women at delivery using latex agglutination and a combination of four PCR methods. Antibiotic resistance was tested in 449 isolates. Capsular genotyping gave a result in all except three of 426 isolates. Fifty-nine of 426 isolates could not be typed by latex agglutination. Agreement between serotyping and genotyping was shown in 303 (71.1%) of the isolates. 10.2% of the isolates were resistant to erythromycin, 9.6% to clindamycin, 76.6% to tetracycline and none to penicillin. In conclusion, a substantial proportion of the colonizing strains were non-typeable by serotyping, but typeable by genotyping. This suggests that a diagnostic genotyping strategy is preferable to serotyping of the GBS polysaccharide capsule in colonized, pregnant women.
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: a.k.brigtsen@medisin.uio.no.
authors.forename: Anne Karin
authors.initials: AK
authors.lastname: Brigtsen
authors.affiliation: Department of Microbiology, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Lumnije
authors.initials: L
authors.lastname: Dedi
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Microbiology, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Kjetil K
authors.initials: KK
authors.lastname: Melby
authors.affiliation: Department of Microbiology, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Mona
authors.initials: M
authors.lastname: Holberg-Petersen
authors.affiliation: Department of Medical Microbiology, St. Olavs University Hospital, Trondheim, Norway; Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Radtke
authors.affiliation: Department of Medical Microbiology, St. Olavs University Hospital, Trondheim, Norway.
authors.forename: Randi Valsø
authors.initials: RV
authors.lastname: Lyng
authors.affiliation: Department of Microbiology, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Lise Lima
authors.initials: LL
authors.lastname: Andresen
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Obstetrics and Gynaecology, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Anne Flem
authors.initials: AF
authors.lastname: Jacobsen
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Neonatal Intensive Care, Oslo University Hospital Ullevaal, Oslo, Norway.
authors.forename: Drude
authors.initials: D
authors.lastname: Fugelseth
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Andrew
authors.initials: A
authors.lastname: Whitelaw
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology*; D011446:Prospective Studies; D012703:Serotyping / Q000379:methods*; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
keywords: Genotyping; Group B Streptococcus; Pregnancy; Serotype; Serotyping; Streptococcus agalactiae