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Published on: September 25, 2014
Evaluation of universal antenatal screening for group B streptococcus
Melissa K Van Dyke1, Christina R Phares, Ruth Lynfield
1Epidemic Intelligence Service Program, Office of Workforce and Career Development, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Insights
Universal screening for Group B Streptococcus (GBS) in pregnant women significantly increased after 2002 national guidelines. Despite improved screening, early-onset GBS disease persists, particularly in preterm infants, highlighting areas for further prevention strategies.
Area of Science:
- Neonatal infections
- Maternal health
- Infectious disease epidemiology
Background:
- Group B streptococcal (GBS) disease is a leading cause of infection in newborns within the first week of life.
- National guidelines in 2002 mandated universal antenatal screening for GBS colonization to guide intrapartum chemoprophylaxis.
Purpose of the Study:
- To evaluate the implementation and impact of universal GBS screening guidelines on intrapartum antibiotic use and early-onset GBS disease.
- To compare GBS screening practices and outcomes between 2003-2004 and a previous period (1998-1999).
Main Methods:
- Retrospective cohort study using data from the 10-state Active Bacterial Core surveillance system.
- Abstracted labor and delivery records for live births and all cases of early-onset GBS disease in infants <7 days old.
- Compared screening and antibiotic administration rates with a similar 1998-1999 study.
Main Results:
- GBS screening rates increased from 48.1% (1998-1999) to 85.0% (2003-2004), with intrapartum antibiotic exposure rising from 26.8% to 31.7%.
- Chemoprophylaxis was given to 87.0% of GBS-positive term-delivering women but only 63.4% of preterm women with unknown status.
- Overall early-onset GBS disease incidence was 0.32/1000 live births; preterm infants had higher incidence (0.73/1000) but most cases (74.4%) occurred in term infants. Missed screening contributed to 13.4% of GBS cases in term infants.
Conclusions:
- National guidelines for universal GBS screening were rapidly adopted by healthcare providers.
- Improvements in managing preterm deliveries and optimizing laboratory processes for GBS culture results are crucial for further reducing early-onset GBS disease.
Background:
Group B streptococcal disease is one of the most common infections in the first week after birth. In 2002, national guidelines recommended universal late antenatal screening of pregnant women for colonization with group B streptococcus to identify candidates for intrapartum chemoprophylaxis.
Methods:
We evaluated the implementation of the guidelines in a multistate, retrospective cohort selected from the Active Bacterial Core surveillance, a 10-state, population-based system that monitors invasive group B streptococcal disease. We abstracted data from the labor and delivery records of a stratified random sample of live births and of all cases in which the newborn had early-onset group B streptococcal disease (i.e., disease in infants <7 days of age) in 2003 and 2004. We compared our results with those from a study with a similar design that evaluated screening practices in 1998 and 1999.
Results:
We abstracted records of 254 births in which the infant had group B streptococcal disease and 7437 births in which the infant did not. The rate of screening for group B streptococcus before delivery increased from 48.1% in 1998-1999 to 85.0% in 2003-2004; the percentage of infants exposed to intrapartum antibiotics increased from 26.8% to 31.7%. Chemoprophylaxis was administered in 87.0% of the women who were positive for group B streptococcus and who delivered at term, but in only 63.4% of women with unknown colonization status who delivered preterm. The overall incidence of early-onset group B streptococcal disease was 0.32 cases per 1000 live births. Preterm infants had a higher incidence of early-onset group B streptococcal disease than did term infants (0.73 vs. 0.26 cases per 1000 live births); however, 74.4% of the cases of group B streptococcal disease (189 of 254) occurred in term infants. Missed screening among mothers who delivered at term accounted for 34 of the 254 cases of group B streptococcal disease (13.4%). A total of 61.4% of the term infants with group B streptococcal disease were born to women who had tested negative for group B streptococcus before delivery.
Conclusions:
Recommendations for universal screening were rapidly adopted. Improved management of preterm deliveries and improved collection, processing, and reporting of culture results may prevent additional cases of early-onset group B streptococcal disease.
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