Advertisement |
| |
 |
| |
Previous Article | Next Article 
AAP News Vol. 21 No. 3
September 2002, p. 118
© 2002 American Academy of Pediatrics
CDC revises group B strep prevention guidelines
Carol J. Baker, M.D., FAAP
| |
Dr. Baker
|
|
All pregnant women should be screened at 35 to 37 weeks of gestation for group B streptococcal (GBS) colonization, and identified carriers should be given intravenous penicillin as soon as possible after hospital admission through delivery, according to revised guidelines from the U.S. Centers for Disease Control and Prevention (CDC) (
MMWR. 2002; 51(RR11):1-22[Medline]). The recommendations also are available at www.cdc.gov/groupbstrep.
| |
Group B streptococcal pneumonia in a neonate.
|
|
Previous CDC guidelines for GBS prevention approved in 1996 by the American College of Obstetricians and Gynecologists (ACOG) and the Academy allowed either an intrapartum risk factor-based or an antenatal GBS screening culture method to select women for intrapartum antibiotic prophylaxis (IAP). However, recent data directly comparing the two methods in 5,144 births demonstrated that culture screening was over 50% more effective than a risk-based strategy in preventing early-onset GBS disease in neonates (
Schrag S, et al. N Engl J Med. 2002;347:233-239[Abstract/Free Full Text]). These data prompted reconsideration of prior guidelines.
Impact of prior guidelines
Since the publication of the first AAP guidelines in 1992, there has been a 70% reduction in the number of early-onset GBS disease cases, a decline attributed to the efficacy of maternal IAP and widespread implementation of 1996 "consensus" recommendations from CDC, ACOG and the Academy.
Despite this substantial decline, cases still occur, and several observational studies have indicated that many cases have been born to women with no defined risk factors for infant GBS disease (preterm labor at less than 37 weeks, rupture of membranes for more than 18 hours, intrapartum fever of 100.4 degrees F or higher, GBS bacteriuria, prior delivery of an infant with GBS disease).
The new CDC data provide the first direct comparison of the two methods for identifying women for IAP. Culture-based screening not only was more effective but also was more often associated with administration of intravenous penicillin more than four hours before delivery. Hopefully, adoption of universal GBS culture screening will result in an even greater reduction in the incidence of early-onset GBS disease.
Changes in the 1996 recommendations
Many of the 2002 CDC recommendations outlined in Prevention of Perinatal GBS Disease are the same as the 1996 guidelines from CDC, ACOG and the Academy (see Figure 1).
- Penicillin remains the IAP drug of choice.
- Women with unknown GBS status at delivery are managed by the risk-based approach.
- GBS culture-negative women do not need IAP.
- Women with GBS bacteriuria during the current pregnancy or who previously have given birth to an infant with invasive GBS disease should receive IAP.
- GBS-positive women without bacteriuria should not receive antenatal antibiotic therapy for GBS colonization.
In addition to culture screening as the only acceptable prevention method, the new recommendations:
- update regimens for penicillin-allergic women (cefazolin is suggested for patients at low risk for anaphylaxis),
- provide detailed instructions for collection of lower vaginal and rectal swabs, GBS culture processing and susceptibility testing of isolates,
- present an algorithm for management of obstetrical patients with threatened preterm delivery,
- recommend against GBS prophylaxis in women undergoing cesarean deliveries without preceding labor or membrane rupture, and
- reiterate that maternal IAP is an interim prevention strategy until GBS vaccines achieve licensure.
Management of newborns
Representatives from the AAP Committees on Infectious Diseases and Fetus and Newborn assisted in preparation of the CDC’s recommendations regarding management of newborns born to women receiving IAP for GBS prevention. Variations in the management algorithm (see Figure 2) that incorporate individual circumstances or institutional preferences may be appropriate.
Based on information since the publication of the 1997 AAP guidelines, an approach for empiric management of the neonate born to a mother with suspected chorioamnionitis is provided.
The new recommendations also contain the following changes:
- If a woman is suspected of having chorioamnionitis, her newborn should have a full diagnostic evaluation and receive empiric broad spectrum therapy (e.g., ampicillin and gentamicin) pending culture results, regardless of the infant’s clinical condition at birth or gestational age.
- When a neonate has clinical signs of sepsis, a full diagnostic evaluation should include a lumbar puncture, if feasible. If the lumbar puncture has been deferred and the therapy is continued more than 48 hours because of suspected infection, cerebrospinal fluid should be obtained for routine studies and culture.
- In addition to penicillin or ampicillin, IAP with cefazolin at least four hours before delivery is considered adequate, because cefazolin achieves bactericidal con- centrations against GBS in amniotic fluid three hours after an IAP dose. The effectiveness of other antimicrobial agents in preventing GBS is unknown.
- Hospital discharge as early as 24 hours after birth may be reasonable under certain circumstances, specifically when the infant is born after four or more hours of maternal IAP, is 38 weeks’ gestation or more, appears healthy, and meets all discharge criteria, including care by an individual able to comply fully with instructions for home observation.
Dr. Baker is a member of the AAP Committee on Infectious Diseases.
