Group B Streptococcus (GBS) remains a leading cause of invasive disease in neonates and certain adult populations including pregnant women. The development of GBS disease is initiated by the asymptomatic colonization of the female genital tract and during pregnancy can be associated with chorioamnionitis, puerperal endometritis and preterm labor. Approximately 20-30% of healthy women are colonized rectovaginally with GBS; the majority of infants born to these women will themselves become colonized with the bacterium. Newborn infection also results from ascending infection of the bacterium through the placental membranes to initiate infection in utero. In the United States national guidelines were published in 2002 that focused on a single strategy of universal screening for GBS carriage of pregnant women at 35-37 weeks of gestation plus intrapartum antibiotic prophylaxis for all women who are carriers. However, current routine screening and antibiotic prophylaxis have fallen short of complete prevention of GBS transmission and GBS remains a leading cause of neonatal infection. This proposal seeks to investigate the ability of Streptococcus salivarius, a predominant member of the native human oral microbiota, to control GBS colonization. Preliminary studies suggest that the bacteriocin producing S. salivarius probiotic strain K12 limits GBS growth in vitro and in vivo. Using our established mouse model of GBS vaginal colonization, mice will be colonized with GBS and then treated vaginally with K12 to determine the impact on GBS vaginal persistence. Different treatment and timing regimens will be compared as will the role of bacitracin production and the impact on the host immune response. These studies will provide fundamental insights into the potential of using a probiotic bacterium as a preventative therapy to control GBS vaginal colonization and thereby prevent its transmission to the neonate during pregnancy.

Public Health Relevance

Group B Streptococcus (GBS) remains a leading cause of invasive disease in neonates and certain adult populations including pregnant women. The development of GBS disease is initiated by the asymptomatic colonization of the female genital tract (FGT) and during pregnancy can be associated with chorioamnionitis, puerperal endometritis and preterm labor. This research proposal seeks to analyze the use of a probiotic strain, Streptococcus salivarius K12, to prevent or limit GBS colonization. Prevention of GBS persistence in the FGT would be a critical first step toward preventing neonatal transmission, infection and disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Small Research Grants (R03)
Project #
1R03AI123877-01
Application #
9093174
Study Section
Special Emphasis Panel (ZRG1-IDM-B (80))
Program Officer
GU, Xin-Xing
Project Start
2016-02-10
Project End
2018-01-31
Budget Start
2016-02-10
Budget End
2017-01-31
Support Year
1
Fiscal Year
2016
Total Cost
$75,000
Indirect Cost
$25,000
Name
San Diego State University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
073371346
City
San Diego
State
CA
Country
United States
Zip Code
92182
Patras, Kathryn A; Wescombe, Philip A; Rösler, Berenice et al. (2015) Streptococcus salivarius K12 Limits Group B Streptococcus Vaginal Colonization. Infect Immun 83:3438-44