Intrapartum PCR assay versus antepartum culture for assessment of vaginal carriage of group B streptococci in a Danish cohort at birth

• Published in: PloS one Vol. 12; no. 7; p. e0180262
• Main Authors: Khalil, Mohammed Rohi, Uldbjerg, Niels, Thorsen, Poul Bak, Møller, Jens Kjølseth
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 05.07.2017; Public Library of Science (PLoS)
• Subjects: Adult; Age; Antibiotics; Antiretroviral drugs; Assaying; Biology and Life Sciences; Births; Carriers; Childbirth & labor; Comparative analysis; Culture; Denmark - epidemiology; Diagnosis; Disease prevention; Female; Gestation; Gestational Age; Group dynamics; Gynecology; Host-Pathogen Interactions; Humans; Infant, Newborn; Infections; Likelihood ratio; Medicine and Health Sciences; Neonates; Newborn babies; Obstetrics; Parturition; People and Places; Polymerase chain reaction; Polymerase Chain Reaction - methods; Population; Pregnancy; Pregnancy Complications, Infectious - diagnosis; Pregnancy Complications, Infectious - epidemiology; Pregnancy Complications, Infectious - microbiology; Prenatal Care - methods; Prenatal diagnosis; Prevalence; Prospective Studies; Rectum; Reproducibility of Results; Research and Analysis Methods; Sensitivity; Sensitivity and Specificity; Sepsis; Streptococcal infections; Streptococcal Infections - diagnosis; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococcus; Streptococcus agalactiae - genetics; Streptococcus agalactiae - physiology; Streptococcus infections; Vagina; Vagina - microbiology; Vaginal diseases; Womens health; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0180262

The aim of this study was to compare the performances of two strategies for predicting intrapartum vaginal carriage of group B streptococci (GBS). One strategy was based on an antepartum culture and the other on an intrapartum polymerase chain reaction (PCR). We conducted a prospective observational study enrolling 902 pregnant women offered GBS screening before delivery by two strategies. The Culture-strategy was based on vaginal and rectal cultures at 35-37 weeks' gestation, whereas the PCR-strategy was based on PCR assay on intrapartum vaginal swab samples. An intrapartum vaginal culture for GBS was used as the reference standard from which the performances of the 2 strategies were evaluated. The reference standard showed a GBS-prevalence of 12%. The culture-strategy performed with a sensitivity of 82%, specificity of 91%, positive predictive value (PPV) of 55%, negative predictive value (NPV) of 98%, and Likelihood ratio (LH+) of 9.2. The PCR-strategy showed corresponding values as sensitivity of 83%, specificity of 97%, PPV of 78%, NPV of 98%, and LH+ of 27.5. We conclude that in a Danish population with a low rate of early-onset neonatal infection with GBS, the intrapartum PCR assay performs better than the antepartum culture for identification of GBS vaginal carriers during labor.