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Updated: Oct 10, 2025
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Probiotic interventions to reduce antepartum Group B streptococcus colonization: A systematic review and
Lisa Hanson1, Leona VandeVusse2, Emily Malloy3
1Klein Endowed Professor and Associate Director, Marquette University College of Nursing, Midwifery Program, Milwaukee, WI USA.
Insights
Antenatal probiotics moderately reduce Group B Streptococcus (GBS) colonization by 44%. While promising for primary prevention, further well-controlled trials are needed to confirm efficacy and safety in diverse populations.
Area of Science:
- Microbiology
- Obstetrics and Gynecology
- Preventive Medicine
Background:
- Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and mortality.
- Antenatal GBS colonization poses risks to newborns during delivery.
- Current prevention strategies primarily rely on intrapartum antibiotic prophylaxis, which has limitations.
Purpose of the Study:
- To systematically review and meta-analyze the efficacy of probiotic interventions in reducing antenatal GBS colonization.
- To evaluate the safety and effectiveness of probiotics as a primary prevention strategy for GBS.
Main Methods:
- Systematic review and meta-analysis of published studies.
- Inclusion of studies on probiotic interventions containing Lactobacillus or Streptococcus species.
- Analysis of clinical trials involving antenatal participants with known or unknown GBS status.
Main Results:
- The meta-analysis included six clinical trials (n=709) and found that antenatal probiotics decreased the probability of a positive GBS result by 44% (OR=0.56, p=0.02).
- In vitro studies demonstrated that probiotics exhibit antagonistic activity against GBS through acidification, immune modulation, and adhesion.
- Only one of the ten reviewed clinical trials had a low risk of bias.
Conclusions:
- Probiotics represent a moderately effective intervention for reducing antenatal GBS colonization.
- Probiotic interventions appear safe and effective for primary prevention of antenatal GBS colonization.
- Further well-controlled trials with diverse populations are necessary to elucidate influencing variables and confirm clinical utility.
Objective:
To systematically review and meta-analyse studies of the efficacy of probiotics to reduce antenatal Group B Streptococcus (GBS) colonisation.
Participants:
Antenatal participants with known positive GBS colonisation or unknown GBS status.
Intervention:
Probiotic interventions containing species of Lactobacillus or Streptococcus.
Design:
Systematic review and meta-analysis.
Measurements And Findings:
The systematic review included 10 studies. Five articles contained in vitro studies of probiotic interventions to determine antagonistic activity against GBS. Six clinical trials of probiotics to reduce antenatal GBS were systematically reviewed and meta-analysed. The meta-analysis revealed that the use of an antenatal probiotic decreased the probability of a positive GBS result by 44% (OR = 0.56, 95% CI = 8.7%, 194.1%, p = 0.02) (n = 709). However, only one clinical trial of 10 had a low risk of bias.
Key Conclusions:
The probiotic interventions subjected to in vitro testing showed antagonistic activity against GBS through the mechanisms of acidification, immune modulation, and adhesion. The findings of the meta-analysis of the clinical trials revealed that probiotics are a moderately effective intervention to reduce antenatal GBS colonisation. More well-controlled trials with diverse participants and with better elucidation of variables influencing GBS colonisation rates are needed.
Implications For Practice:
Probiotic interventions appear to be a safe and effective primary prevention strategy for antenatal GBS colonisation. Application of this low-risk intervention needs more study but may reduce the need for intrapartum antibiotic prophylaxis in countries or regions where antenatal GBS screening is used. Midwives can be instrumental in conducting and supporting larger well-controlled clinical trials.
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