Related Experiment Video
Updated: Nov 16, 2025
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Relationship between intrapartum antibiotic prophylaxis and group B streptococcal colonization dynamics in Japanese
Meiwa Shibata1, Miyuki Morozumi2, Naonori Maeda3
1Department of Pediatrics, Yokohama Rosai Hospital, Japan; Department of Infectious Diseases, Keio University School of Medicine, Japan.
Insights
Intrapartum antibiotic prophylaxis (IAP) for pregnant women in Japan effectively reduces early group B Streptococcus (GBS) neonatal infections, but its protective effect may diminish within weeks after birth.
Area of Science:
- Obstetrics and Gynecology
- Neonatal Health
- Infectious Disease Epidemiology
Background:
- Japan recommends universal screening for group B Streptococcus (GBS) colonization in pregnant women and intrapartum antibiotic prophylaxis (IAP) to prevent neonatal GBS infections.
- Limited data exist on GBS colonization dynamics in Japanese mother-neonate pairs.
Purpose of the Study:
- To investigate the dynamics of GBS colonization in Japanese mother-neonate pairs.
- To assess the transmission of GBS from mothers to neonates.
- To evaluate the duration of protection offered by IAP.
Main Methods:
- Prospective cohort study (July 2018 - March 2019).
- Rectovaginal samples from pregnant women (33-37 weeks gestation).
- Neonatal nasopharyngeal and rectal samples collected at birth, 1 week, and 1 month.
- GBS detection via real-time PCR and culture; capsular typing performed.
Main Results:
- Maternal and neonatal GBS-positivity rates were 22.7% and 8.8%, respectively.
- IAP was administered to 96.5% of GBS-positive mothers.
- Neonates born to GBS-positive mothers had significantly higher GBS positivity (19.3% vs. 5.7%).
- GBS positivity in neonates increased with maternal colony count and was higher at 1 month postpartum than at 1 week.
- Consistent GBS capsular types (Ib, III, V, VI) were observed in mother-neonate pairs.
Conclusions:
- IAP demonstrates high administration rates in Japan for GBS-positive mothers.
- Neonatal GBS colonization is significantly associated with maternal GBS status.
- The effectiveness of IAP in preventing GBS transmission to neonates appears limited to a few weeks post-birth.
Introduction:
In Japan, universal screening for group B streptococcal (GBS) colonization in pregnant women and intrapartum antibiotic prophylaxis (IAP) are recommended to prevent neonatal GBS infection. However, the dynamics of GBS colonization in Japanese mother/neonate pairs have not been adequately studied.
Methods:
A prospective cohort study was conducted from July 2018 to March 2019. Rectovaginal samples were collected from pregnant women (33-37 gestation weeks) once. In neonates, nasopharyngeal and rectal samples were collected at three time points: after birth, 1 week after birth, and 1 month after birth. All samples were analyzed for GBS using real-time PCR testing and culture methods. Capsular typing was performed for all GBS isolates and GBS-positive samples using real-time PCR testing.
Results:
The overall maternal and neonatal GBS-positivity rates were 22.7% (57/251) and 8.8% (22/251), respectively. IAP for GBS-positive mothers (96.5%) was highly administered. Eleven (19.3%) neonates born to GBS-positive mothers were GBS-positive, which was significantly higher than the 11 (5.7%) neonates born to GBS-negative mothers. The rate of GBS-positivity in neonates increased with an increased number of GBS colonies in mothers. More neonates were GBS-positive 1 month after birth than 1 week after birth, and there was a higher rate of GBS-positive rectal swabs than nasopharyngeal swabs. Capsular types of GBS that were isolated from each mother and neonate pair were the same, namely, Ib, III, V, and VI.
Conclusions:
These findings indicate that the efficacy of IAP in preventing GBS transmission to neonates might be limited to within a few weeks after birth.
Related Concept Videos
01:26Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
01:22Development of Immunocompetence
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...
01:22Healthcare Associated Infections II: Preventive Measures
The best practices for preventing healthcare-associated infections include hand hygiene, patient risk...
01:26Healthcare Associated Infections I: Iatrogenic, Exogenic and Endogenic
HAIs significantly increase the cost of health care. Extended stays in healthcare institutions, increased disability, increased costs of medications, including specialized antibiotics, and prolonged recovery times add to the patient's expenses and the healthcare institution and funding bodies.
01:18Surface Membrane Barriers
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...