Intrapartum group B Streptococcus screening in the labor ward by Xpert® GBS real-time PCR

Eur J Clin Microbiol Infect Dis. 2018 Feb;37(2):265-270. doi: 10.1007/s10096-017-3125-2. Epub 2017 Oct 29.


Group B Streptococcus (GBS) is the leading cause of neonatal infections in industrialized countries. Intrapartum antibiotic prophylaxis (IAP) given to colonized parturients is a key step for the prevention of neonatal early-onset infection. We compared the performances of Xpert® GBS polymerase chain reaction (PCR) (Cepheid, Sunnyvale, CA, USA) as a point-of-care system in labor wards to standard culture for intrapartum GBS detection. Pregnant women with a GBS-positive antenatal screening were prospectively included. A vaginal double swab was collected at the time of delivery for point-of-care Xpert® GBS PCR and GBS culture. A total of 565 pregnant women were included. Valid Xpert® GBS results were obtained for 488 (86.4%) women on the first attempt. Repeat testing improved the PCR success to 516 (91.3%) women. Among the 305 women positive for GBS by culture at delivery, only 238 (78.0%) were positive by Xpert® GBS PCR, cycle thresholds being correlated to culture quantification. Among 260 women negative for GBS culture, 56 (21.5%) were positive by Xpert® GBS PCR, including 50 where IAP was initiated before vaginal sampling. Overall, among the 565 women with GBS antenatal positive culture, only 335 (59.3%) were still positive at delivery whatever the technique used, resulting in unnecessary IAP for 40% of them. This large cohort study comparing intrapartum to antepartum GBS detection provides evidence that (i) Xpert® GBS PCR might be a valuable solution for intrapartum GBS detection compared to culture-based strategies and (ii) laboratory training of non-specialized staff is mandatory to reach the performances required for point-of-care tests.

MeSH terms

  • Adult
  • Anti-Bacterial Agents / therapeutic use
  • Antibiotic Prophylaxis
  • Female
  • Humans
  • Infant, Newborn
  • Infant, Newborn, Diseases / diagnosis*
  • Infant, Newborn, Diseases / drug therapy
  • Infant, Newborn, Diseases / microbiology
  • Mass Screening / methods*
  • Obstetrics and Gynecology Department, Hospital
  • Point-of-Care Testing*
  • Pregnancy
  • Pregnancy Complications, Infectious / diagnosis*
  • Pregnancy Complications, Infectious / drug therapy
  • Pregnancy Complications, Infectious / microbiology
  • Real-Time Polymerase Chain Reaction
  • Streptococcal Infections / diagnosis*
  • Streptococcal Infections / drug therapy
  • Streptococcal Infections / microbiology
  • Streptococcus agalactiae / genetics
  • Vagina / microbiology


  • Anti-Bacterial Agents