CDC Expert Commentary

Updated Guidelines for Prevention of Perinatal Group B Strep Disease

Jennifer R. Verani, MD, MPH

Disclosures

December 13, 2010

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Hi, I'm Dr. Jennifer Verani.

Thanks for watching this CDC Expert Video Commentary on Medscape.

I'm going to talk about updated Guidelines for the Prevention of Perinatal Group B Streptococcal Disease (GBS).

Despite excellent progress in reducing the burden of GBS disease in the first week of life, commonly referred to as early-onset disease, GBS continues to be the leading cause of early-onset sepsis and meningitis in the United States.

The primary risk factor for early-onset GBS disease is maternal colonization with GBS. Colonization occurs in about 10%-30% of pregnant women. Intrapartum antibiotic prophylaxis (IAP) is highly effective at preventing early-onset GBS disease among infants born to colonized women.

CDC first issued guidelines on use of IAP for prevention of GBS disease in 1996, and then revised guidelines in 2002. The 2002 guidelines recommended that all women undergo vaginal-rectal screening for GBS colonization at 35-37 weeks' gestation to identify which women should receive IAP. Implementation of the 2002 guidelines has been quite good.

One study found that 85% of pregnant women were screened for GBS colonization.[1] Among those screened, 98% had results available at time of delivery, and 85% of women with an indication for IAP were administered antibiotics.

Nonetheless, there is room for improvement. For example, despite a recommendation that all women delivering preterm with unknown GBS status should be screened for GBS on admission and receive IAP, only 18% of those women were screened, and less than two thirds received IAP.

Another area needing improvement is choice of antibiotic for penicillin-allergic women. Women with a penicillin allergy and an indication for IAP should receive cefazolin unless they are at high risk for anaphylaxis. However, 70% of penicillin-allergic women at low risk for anaphylaxis who received IAP were given clindamycin instead. This drug is not established as effective in preventing early-onset GBS disease, does not reach the fetal circulation or amniotic fluid well, and an increasing proportion of GBS isolates are resistant to it.

Revised 2010 GBS guidelines from CDC were recently released. They were developed using an evidence-based approach in collaboration with several professional associations, including ACOG, AAP, ACNM, AAFP and ASM. Central prevention approaches remain unchanged from the 2002 guidelines:

Pregnant women should undergo vaginal-rectal screening at 35-37 weeks' gestation.

IAP is recommended for GBS-positive women, as well as those with unknown GBS status who deliver at less than 37 weeks' gestation, have an intrapartum temperature of 100.4 F or greater, or have rupture of membranes for 18 hours or longer.

IAP is recommended for women who had a previous infant with invasive GBS disease or those with GBS bacteriuria during the current pregnancy. Penicillin remains the preferred agent with ampicillin as an acceptable alternative.

So what's new in the 2010 guidelines?

There are expanded options for laboratory detection of GBS, including use of pigmented media and PCR assays, and a revised colony count threshold for laboratories to report GBS in the urine of pregnant women.

There are revised algorithms for GBS screening and use of IAP for women with threatened preterm delivery, including one algorithm for preterm labor and one for preterm premature rupture of membranes.

Recommendations for IAP agents are presented in an algorithm in an effort to promote use of the most appropriate antibiotic for penicillin-allergic women. The new guidelines also contain a minor change to penicillin dosing for those women not allergic to penicillin.

The neonatal management algorithm's scope was expanded to apply to all newborns. It provides management recommendations that depend upon clinical appearance of the neonate and other risk factors such as maternal chorioamnionitis, adequacy of IAP if indicated for the mother, gestational age, and duration of membrane rupture.

Changes were made to the algorithm to reduce unnecessary evaluations in well-appearing newborns at relatively low risk for early-onset GBS disease.

To access the 2010 guidelines and other GBS resources, please visit our website.

Thank you.

Web Resources

CDC Group B Streptococcus Website, Clinician Resources

Prevention of Perinatal Group B Streptococcal Disease, 2010 Guidelines

Printable Algorithms and Tables from the 2010 GBS Prevention Guidelines

Slide Sets about the 2010 GBS Prevention Guidelines

Questions and Answers about the 2010 GBS Prevention Guidelines

Van Dyke MK, Phares CR, Lynfield R, et al. Evaluation of universal antenatal screening for group B Streptococcus. N Engl J Med 2009;360:2626–36. http://www.nejm.org/doi/full/10.1056/NEJMoa0806820

Jennifer R. Verani, MD MPH is a medical epidemiologist in the Respiratory Diseases Branch (RDB), National Center for Immunization and Respiratory Diseases (NCIRD), Centers for Disease Control and Prevention (CDC). Dr. Verani obtained her medical degree and a master's degree in internal health from Harvard University. She completed her pediatrics residency at the Children's Hospital of New York-Presbyterian (Columbia University Medical Center), where she was in the Community Pediatrics track.

Dr. Verani came to CDC in 2006 as an Epidemic Intelligence Service Officer in the Division of Parasitic Diseases, where she worked primarily on neglected tropical diseases. In 2008 she joined her current branch, where her work focuses on the prevention of pneumonia and neonatal sepsis, both internationally and within the United States. Dr. Verani has led the 2010 revision of the CDC Guidelines for Prevention of Perinatal Group B Streptococcal Disease.

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