The Effect of Intrapartum Vancomycin on Vaginal Group B Streptococcus Colony Counts

Am J Perinatol. 2019 May;36(6):555-560. doi: 10.1055/s-0038-1675622. Epub 2018 Nov 16.

Abstract

Objective: To define the temporal relationship between intrapartum intravenous vancomycin administration and vaginal group B streptococcus (GBS) colony counts.

Study design: Prospective cohort study conducted from October 2014 to February 2017. Women with antenatal cultures demonstrating GBS colonization and a plan for vancomycin administration were eligible. Intrapartum vaginal cultures were collected prior to the first vancomycin infusion and every 2 hours up to five collections or delivery. Results were analyzed in two groups: participants with at least one positive intrapartum culture and those without any positive intrapartum cultures.

Results: A total of 63 women were enrolled. Among consented women, a total of 8 were excluded and 3 participants' cultures were never plated, thus leaving a total of 52 women for analysis. The degree of vaginal GBS colonization varied between subjects and was not normally distributed. Colony counts dropped rapidly from hour 0 to hour 2 (median: 6.0 × 108 vs. 1.0 × 108, p < 0.01). Standardizing hour 0 colony counts to 100%, the percent decline in colony counts from hour 0 to hour 2 was significant (p = 0.03), and at each subsequent time point fell further.

Conclusion: GBS vaginal colony counts fall rapidly after intrapartum vancomycin administration.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Anti-Bacterial Agents / therapeutic use*
  • Colony Count, Microbial
  • Female
  • Humans
  • Injections, Intravenous
  • Pregnancy
  • Pregnancy Complications, Infectious / drug therapy*
  • Pregnancy Complications, Infectious / microbiology
  • Prospective Studies
  • Streptococcal Infections / drug therapy*
  • Streptococcus agalactiae / drug effects*
  • Streptococcus agalactiae / isolation & purification
  • Time Factors
  • Vagina / microbiology*
  • Vancomycin / therapeutic use*

Substances

  • Anti-Bacterial Agents
  • Vancomycin