The impact of oral probiotic use on vaginal Group B Streptococcal colonisation rates in pregnant women: a pilot randomised controlled study

Background: Group B Streptococcus (GBS) is the leading cause of bacterial infections in the neonate in the developed world. This bacteria is passed from a woman’s vagina to her newborn during the process of labour and birth, potentially causing pneumonia, septicaemia and meningitis in the infant. In order to prevent neonatal GBS infections most hospitals have protocols in place that identify pregnant women at risk of infecting their newborns and give these women intravenous antibiotics in labour to inhibit the transmission. The disadvantages of intravenous antibiotics in labour are the development of antibiotic resistance in GBS and non-GBS pathogens, the inhibition of the colonisation of the newborn’s gut with the appropriate flora and the medicalisation of childbirth. It has been shown that women with higher colonisation of vaginal Lactobacillus are more likely to have no detectable vaginal GBS. This raises the hypothesis: Would increasing the colonisation rates of Lactobacillus in pregnant women’s vaginas result in a decrease in GBS colonisation rates? A pilot randomised controlled trial is proposed to determine if oral probiotics may be a strategy for decreasing GBS vaginal colonisation rates by increasing vaginal Lactobacillus rates. Methods: A sample of thirty GBS positive pregnant women will be recruited. The GBS status of these women will be determined by the routine lower vaginal swabs that are self-collected by all women in the antenatal clinic at the proposed hospital site at thirty-six weeks gestation. These women will be randomised into control and intervention groups. The control group will continue with standard care, the intervention group will receive standard care and take a daily dose of oral probiotics for three weeks. After three weeks both groups will repeat the self-collection of a lower vaginal swab. It is anticipated that the data collection phase will take approximately three months, commencing in January 2011. Ethics approval for this project has been granted. Expected Outcomes: It is expected that a significant numberof women in the intervention group will be GBS negative after three weeks of oral probiotics when compared with the control. A positive outcome would then become the basis of a larger randomised control trial.