Intrapartum antibiotic prophylaxis for the prevention of perinatal group B streptococcal disease: experience in the United States and implications for a potential group B streptococcal vaccine.

Group B Streptococcus (GBS) emerged as the leading cause of newborn infection in the United States in the 1970s. In the 1980s clinical trials demonstrated that giving intrapartum intravenous ampicillin or penicillin to mothers at risk was highly effective at preventing invasive GBS disease in the first week of life (early-onset). In 1996, the first national guidelines for the prevention of perinatal GBS disease were issued; these recommended either antenatal screening for GBS colonization and intrapartum antimicrobial prophylaxis (IAP) to colonized women, or targeting IAP to women with certain obstetric risk factors during labor. In 2002, revised guidelines recommended universal antenatal GBS screening. A multistate population-based review of labor and delivery records in 2003-2004 found 85% of women had documented antenatal GBS screening; 98% of screened women had a colonization result available at labor. However, missed opportunities for prevention were identified among women delivering preterm and among those with penicillin allergy, and more false negative GBS screening results were observed than expected. The incidence of invasive early-onset GBS disease decreased by more than 80% from 1.8 cases/1000 live births in the early 1990s to 0.26 cases/1000 live births in 2010; from 1994 to 2010 we estimate that over 70,000 cases of EOGBS invasive disease were prevented in the United States. IAP effectiveness is similar and high among term (91%) and preterm (86%) infants when first line therapy is received for at least 4h. However, early-onset disease incidence among preterm infants remains twice that of term infants; moreover disease among infants after the first week of life (late-onset disease) has not been impacted by IAP. The US experience demonstrates that universal screening and IAP for GBS-colonized women comprise a highly effective strategy against early-onset GBS infections. Maximizing adherence to recommended practices holds promise to further reduce the burden of early-onset GBS disease. Yet there are also inherent limitations to universal screening and IAP. Some of these could potentially be addressed by an efficacious maternal GBS vaccine.

Schrag SJ ，Verani JR 《-》

Group B streptococcus colonization in pregnancy and neonatal outcomes: a three-year monocentric retrospective study during and after the COVID-19 pandemic.

Serra G ，Scalzo LL ，Giordano M ，Giuffrè M ，Trupiano P ，Venezia R ，Corsello G ... -  《-》

A rapid intrapartum test for group B Streptococcus to reduce antibiotic usage in mothers with risk factors: the GBS2 cluster RCT.

Daniels J ，Dixon EF ，Gill A ，Bishop J ，D'Amico M ，Ahmed K ，Dodds J ，Tryposkiadis K ，Wilks M ，Millar M ，Husain S ，Gray J ，Whiley A ，Moore PV ，Munetsi RL ，Hemming K ，Roberts T ，Plumb J ，Deeks J ，Khan KS ，Thangaratinam S ... -  《-》

Association between intrapartum antibiotic prophylaxis for Group B Streptococcus colonization and clinical chorioamnionitis among patients undergoing induction of labor at term.

Rectovaginal colonization with Group B Streptococcus during pregnancy has historically been shown to be associated with an increased risk of clinical chorioamnionitis and peripartum infectious morbidity. Newer observational data in the era of intrapartum antibiotic prophylaxis suggest a possible reversal of this association; however, it is unclear if this is related to differences in labor management for those with and without Group B Streptococcus colonization. We therefore sought to assess the association between intrapartum antibiotic prophylaxis for Group B Streptococcus colonization and clinical chorioamnionitis within the context of a randomized induction of labor trial with a standardized labor protocol. We performed an exploratory secondary analysis of a randomized trial of patients undergoing term induction at a tertiary care center. Patients received third trimester Group B Streptococcus screening and intrapartum antibiotic prophylaxis as routine care. Group B Streptococcus detection was performed using a carrot broth-enhanced subculture to Group B Streptococcus Detect approach (Hardy Diagnostics, Santa Maria, CA). Labor management was protocolized per the trial. Patients with unknown Group B Streptococcus status or who did not receive intrapartum antibiotic prophylaxis, if indicated, were excluded. The primary outcome was diagnosis of clinical chorioamnionitis, compared between patients who received intrapartum antibiotic prophylaxis for known Group B Streptococcus positive status (by culture, history, or Group B Streptococcus bacteriuria) and those who were Group B Streptococcus negative and did not receive intrapartum antibiotic prophylaxis. Secondary outcomes included postpartum endometritis, wound infection, a composite maternal peripartum infectious morbidity, and neonatal outcomes. A total of 491 patients were enrolled in the trial. Of these, 466 had a known Group B Streptococcus status and received or did not receive intrapartum antibiotic prophylaxis accordingly and were included in this analysis: 292 (62.7%) were Group B Streptococcus negative and did not receive intrapartum antibiotic prophylaxis, and 174 (37.3%) were Group B Streptococcus positive and received intrapartum antibiotic prophylaxis. The majority of patients were Non-Hispanic Black (78.1%) and nulliparous (59.7%). There were no differences in demographic, clinical, induction or labor characteristics between groups. Patients who were Group B Streptococcus positive had a 49% lower rate of clinical chorioamnionitis (8.1% vs 14.7%, odds ratio, 0.51; P=.03) and a lower rate of peripartum infectious morbidity (8.1% vs 15.8%, odds ratio, 0.47; P=.02) compared to those who were Group B Streptococcus negative. Infants born to patients who were Group B Streptococcus positive were significantly less likely to be admitted to the neonatal intensive care unit (3.4% vs 15.1%, P<.001). Although Group B Streptococcus colonization has historically been considered a risk factor for clinical chorioamnionitis, in the era of universal antibiotic prophylaxis for Group B Streptococcus positive patients, our findings support the point that intrapartum antibiotic prophylaxis for Group B Streptococcus positivity is associated with lower rates of clinical chorioamnionitis and peripartum infectious morbidity among patients undergoing induction with protocolized labor management. These findings demonstrate that intrapartum antibiotic prophylaxis for Group B Streptococcus may protect against perinatal infectious morbidity, a phenomenon that warrants further investigation.

McCoy JA ，Bromwich K ，Gerson KD ，Levine LD ... -  《-》

Group B Streptococcus colonization status and antibiotic use during labour - a single-centre observational study.

Janczewska I ，Jassem-Bobowicz J ，Hinca K ，Stefanska K ，Domzalska-Popadiuk I ... -  《-》