Effect of oral Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on vaginal Group B Streptococcus colonization and vaginal microbiome in late pregnancy

Abstract

To explore the effects of intervention with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on vaginal Group B Streptococcus (GBS) colonization, pregnancy outcome and vaginal microbiome in GBS-positive women in the third trimester of pregnancy. This study were conducted among 155 women in the third trimester of pregnancy with positive results of GBS culture in the Outpatient Department of Zhujiang Hospital from March to November, 2019. After excluding 32 patients who received lactobacillus intervention for less than 2 weeks or underwent postpartum GBS retesting, the women were divided into oral probiotics intervention group (60 cases) and non-intervention group (63 cases). According to the results of GBS retesting, the 60 women in the intervention group were divided into GBS-negative group (18 cases) and persistent GBS-positive group (42 cases). At the end of the intervention, the rates of negative GBS culture result were calculated and the pregnancy outcomes were compared. From 5 women randomly selected from the intervention group, samples of vaginal secretions were collected before and after the intervention for amplicon sequencing and bioinformatics analysis. At the end of the intervention, the GBS-negative rate in the intervention group was 30% (18/60), as compared with 23% (3/13) in the non-intervention group. Probiotic intervention significantly reduced the incidence of premature rupture of membranes (P < 0.05) and reduced the use of antibiotics during pregnancy (P < 0.05). OTU analysis of the vaginal secretions suggested probiotic intervention decreased the total sequence number and GBS sequence number, increased the species composition, and significantly decreased GBS abundance (P < 0.05). Probiotics intervention also significantly decreased the species abundance of Enterococcus, Staphylococcus and Streptococcus in the vaginal flora (P < 0.05). Intervention with oral probiotics can reduce vaginal GBS colonization in late pregnancy and improve the pregnancy outcome. Lactobacillus is capable of reducing the abundance of GBS and other pathogenic bacteria to improve the microbiome of vaginal flora.