Group B streptococci (GBS) colonizes the vagina and rectum in 10-30% of pregnant women. In the newborn, GBS is a leading cause of neonatal sepsis and a major cause of pneumonia and meningitis. Intrapartum penicillin G prophylaxis aims to prevent early-onset group B streptococci (GBS) sepsis by interrupting vertical transmission. According to the Center of Disease Control and Prevention (CDC) guideline in 2002, a minimum of 4 hours of intrapartum antibiotics prophylaxis is generally recommended to prevent early-onset group B Streptococcous (GBS) because less than 4 hours may not achieve adequate levels drugs. Even with the most valiant of efforts, there will frequently be GBS-positive mothers who arrive at the labor floor and deliver in fewer than 4 hours, especially in multiparous mothers. Preliminary studies as well as data from a large health maintenance organization demonstrated the 40-50%of GBS-colonized women do not receive antibiotics at least 4 hours before delivery due the rapidity of their labors. Newborns of all GBS-positive women who present to labor units and deliver before receiving 4 hours of intrapartum antibiotic prophylaxis are deemed as "at risk" and recommended to undergo blood cultures, complete blood count, and 48 hours of observation. This problem is not easily resolved by antibiotic treatment of the pathogen; thus, such tranditional approaches to patient management need to be re-evaluated.

Probiotics are defined as live micro-organisms which, when administered in an adequate amount, confer a health benefit on the host. Probiotics have been shown to displace and kill pathogens and modulate the immune response by interfering with the inflammatory cascade that leads to preterm labour and delivery. Lactobacilli are the dominant bacteria of vaginal flora and possess antimicrobial properties that regulate other urogenital microbiota. Incomplete cure and recurrence of genitourinary infections lead to a shift of the local flora from a predominance of lactobacilli to coliform uropathogens. Use of Lactobacillus-containing probiotics to restore commensal vaginal flora has been proposed for the treatment and prophylaxis of bacterial urogenital infections. The actual mechanism of action of probiotics in the vagina is probably multifactorial. The production of lactic acid, bacteriocin, and hydrogen peroxide seems to be important, and modulation of immunity is another possible mechanism. The administration of these Lactobacilli by mouth or intravaginally, or both has been shown to be safe and effective in reducing, or treating, or both, urogenital infections. For pregnant women, such restoration could be important to prevent BV and lower the risk of PTL Daily use of oral gelatin capsules containing dried viable Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 has been shown to decreased e risk of bacterial vaginosis and maintain normal lactobacilli vaginal flora. These organisms are antagonistic to the growth and adhesion of various intestinal and urogenital pathogens including Salmonella typhimurium, Shigella sonnei, E coli 0157, toxic shock Staphylococcus aureus, group B streptococci, Enterococcus faecalis, G vaginalis, and uropathogenic E coli. In animal studies, these strains were found to be safe during pregnancy and to enhance the health of mothers and newborns. Studies are under way in Toronto, Ont, to test the effects of these strains on bacterial vaginosis in pregnant women at risk of preterm labour. These lactobacilli might also have a role in preventing vaginal colonization by group B streptococci, organisms that can cause serious illness and even death in newborns. Certain lactobacilli can inhibit growth and adhesion of streptococci in vitro, but whether they can do this in vivo is untested.

This study is a prospective double blind randomized clinical trial. Vaginal and rectal GBS screening culture are carried out for all pregnant women at 35-37 weeks of gestation in our OPD. Subjects with vagina and rectum GBS colonization are invited to participate in our study after informed consent. A total of 200 pregnant women will participate in the study during the 12-months trial period. They are randomly assigned to one of the two groups. The study group is treated with two oral capsules of probiotics once daily (before sleeping) for 14 days, and the control group will take 2 capsules of placebos. Vaginal and rectal GBS culture is repeated for all participators 2 weeks later. All participators will treated according to GBS guideline by CDC in 2002 during laboring.

Much of the current literature has investigated the potential of probiotics in preventing of bacterial vaginosis and preterm labor, but the usefulness of using probiotics as a surrogate or adjunctive therapy for intra-partum antibiotics prophylaxis in GBS colonized pregnant women dose not have any. This is the first study to investigate the role of probiotics in preventing and treating vaginal colonization by GBS in pregnant women. The purpose of this study is to examine whether oral taking Latobacillus-containing probiotics can reduce the GBS colonization rate of vagina and rectum in pregnant women who present with GBS-positive. Through the results of our study, we try to investigate the role of probiotics in preventing the unnecessary tests, admission and antibiotic treatment in newborn with GBS-positive mother who deliver fewer than 4 hours after laboring. We hope our results may have some effects on GBS sepsis protocols.