Preventing early-onset group B streptococcal sepsis: strategy development using decision analysis

Regional Variation of Early-onset Neonatal Group B Streptococcal Disease Prevention Strategies in Mainland China

BACKGROUND

Prevention strategies can reduce the incidence of early-onset group B Streptococcus (GBS) neonatal sepsis (EOGBS). Rates of GBS colonization and infection vary among regions within China. China has not adopted a unified prevention strategy.

METHODS

To assess strategies to reduce EOGBS in China, models were developed to quantify residual EOGBS rates with intrapartum antibiotic prophylaxis in infants ≥ 35 weeks' gestation in risk factor-based and antepartum screening-based strategies. Maternal GBS colonization rates and EOGBS incidence in 3 regions of China (A: Xiamen of Fujian province, B: Shanghai and C: Liuzhou of Guangxi province) were estimated from published data.

RESULTS

Estimates for GBS colonization and attack rates were 21.6%, 11.7% and 6.1% and 1.79, 1.79 and 0.58 per 1000 live births for regions A, B and C, respectively. Modeling predicted that strategies including screening cultures beginning at 36 weeks' gestation and intrapartum antibiotic prophylaxis in 90% of eligible parturients could reduce EOGBS incidence to 0.44, 0.50 and 0.16 per 1000 live births in these regions. In region C, the expected EOGBS rate could be reduced to 0.28 per 1000 using a risk factor-based strategy.

CONCLUSIONS

Different strategies for preventing EOGBS may be needed in different regions of mainland China. Screening strategies may be most appropriate in regions with higher attack rates, even with moderate levels of maternal GBS colonization. In areas with low attack rates, risk factor strategies that reduce morbidity by at least one-third may suffice.

Cost Effectiveness of Latest Recommendations for Group B Streptococci Screening in the United States

OBJECTIVE

To evaluate whether group B streptococci (GBS) screening using the 2010 guideline (screening at 35 0/7-37 6/7 weeks of gestation) compared with the 2019 guideline (screening at 36 0/7-37 6/7 weeks of gestation with re-screening of women with GBS-negative results 5 weeks later) was more cost effective.

METHODS

We constructed a decision-analysis model to compare the outcome of GBS early-onset disease in a hypothetical cohort of 3,614,049 women at 35 0/7 weeks of gestation or greater (the number of live births in 2017 excluding births based on population frequency from 23 to 34 weeks of gestation, women with GBS bacteriuria during the current pregnancy, and those with a history of a previous neonate with GBS disease). We took both a health care and societal perspective and all costs were expressed in 2017 U.S. dollars. Effectiveness was based on neonatal quality-adjusted life years (QALYs) gained. An incremental cost-effectiveness ratio was estimated with a willingness to pay threshold set at $100,000/QALY. All model inputs were derived from the literature. One-way probability and cost sensitivity analysis were performed to investigate model assumptions.

RESULTS

Screening at 36 0/7-37 6/7 weeks of gestation with re-screening of women with GBS-negative results if 5 weeks passed from culture to delivery resulted in a 6% increase in neonatal QALYs gained (2,162 vs 2,037), 12% fewer cases of neonatal death (30 vs 34), and a 10% estimated reduction in total societal health care expenditures related to GBS early-onset disease ($639 million vs $707 million) when compared with the 2010 strategy of only screening at 35 0/7-37 6/7 weeks of gestation. The 2019 approach was cost effective, with an incremental cost-effectiveness ratio of $43,205 per neonatal QALY gained.

CONCLUSION

Screening at 36 0/7-37 6/7 weeks of gestation with a 5-week re-screening for women with GBS-negative results is more cost effective than past strategies used in the United States.

While waiting for a vaccine: opportunities for optimization of neonatal group B streptococcal (GBS) disease prevention in Israel

OBJECTIVE

To quantify effects of different strategies for decreasing neonatal early onset GBS sepsis (EOGBS) in Israel.

STUDY DESIGN

A risk allocation model for EOGBS among infants ≥ 35w was adapted to Israeli data. Effects of strategies for antepartum (APS) and intrapartum (IPS) screening, and intrapartum (IAP) and/or postpartum antibiotic prophylaxis (PAP) were calculated.

RESULTS

Estimated EOGBS attack rates (AR) with APS in 90%, IAP in 90%, may reduce AR to 0.18/1000. A rapid intrapartum test would further decrease AR to 0.16/1000, while reducing IAP from 21.3 to 12.5% of women. For babies with risk factors and GBS+ who do not receive IAP, further risk reduction could be achieved by PAP.

CONCLUSION

IAP remains the main intervention to decrease EOGBS. IAP and PAP together may reduce EOGBS present incidence by 40%. Combining rapid intrapartum screening with selective IAP and selective PAP for remaining gaps, would be the most efficient strategy.

Early-onset group B streptococcal disease in a risk factor-based prevention setting: A 15-year population-based study

BACKGROUND

Intrapartum chemoprophylaxis reduces early-onset group B streptococcal disease (EOGBSD) in newborns. Some guidelines advise that intrapartum antibiotics should be offered following universal antenatal screening for GBS carriage and others recommend intrapartum antibiotics based on clinical risk factors alone. Since 1999, Queensland guidelines have recommended a risk factor-based approach. We examined trends in EOGBSD rates over time in Queensland in the setting of these guidelines and whether management of cases reflected the recommendations.

METHODS

A state-wide retrospective search of pathology databases, allowing near-complete, population-based case identification, was conducted to detect live-born infants from January 2000 to December 2014 with GBS cultured from blood or cerebrospinal fluid within seven days of age. A nested audit of EOGBSD cases comparing two epochs, 2000-2010 and 2011-2014, was performed to determine patient characteristics and guideline adherence for each case.

RESULTS

Mean incidence of EOGBSD in Queensland from 2000 to 2014 was 0.33 per 1000 live births (SD± 0.08) with no changing trend over time. The case-mortality rate in the 2011-2014 epoch was 1.2% compared to 11.9% in 2000-2004 (odds ratio (OR) 0.09, 95% confidence interval (CI) 0.002-0.67). The proportion of EOGBSD cases who were preterm infants decreased from 29.8% to 13.3% (OR 0.36, 95% CI 0.14-0.84). Of cases with risk factors in the 2011-2014 epoch, 46% received intrapartum antibiotics compared to 25% in 2000-2004 (OR 2.49, 95% CI 0.86-7.58, P = 0.09).

CONCLUSIONS

EOGBSD incidence rate in Queensland remained low during 2000-2014. However, both the 2011-2014 case-mortality rate and the proportion of preterm cases significantly decreased. Missed opportunities for intrapartum chemoprophylaxis remain.

[Vaginal colonization by group B streptococcus among pregnant women in the region of Marrakech]

INTRODUCTION

Group B streptococcus is the main etiological agent of maternal and fetal infections, sepsis and meningitis in the term newborns. The objective is to determine group B streptococcal (GBS) carriage rate in vagina of term pregnant women.

METHODS

Vaginal swab was performed prospectively in 275 pregnant women in labor, prior to entering the delivery room over a period of 6 months.

RESULTS

Colonization rate was 20.2%. The bearing was variable according to the gestational age, it constitutes 57.5% between 37 and 38 weeks of amenorrhoea. None of the risk factors was statistically predictive for maternal GBS colonization.

CONCLUSION

Screening should be performed from 37 weeks of amenorrhoea and, as colonization is intermittent, a negative swab result does not ensure that GBS colonization is eradicate at birth.

Vaginal chlorhexidine during labour to prevent early-onset neonatal group B streptococcal infection

BACKGROUND

Although early-onset group B β-hemolytic streptococcus (GBS) infection is rare, it accounts for approximately 30% of neonatal infections, has a high mortality rate, and is acquired through vertical transmission from colonized mothers. Several trials have demonstrated the efficacy of intrapartum antibiotic prophylaxis (IAP) for preventing early-onset disease (EOD). Vaginal disinfection with chlorhexidine during labour has been proposed as another strategy for preventing GBS EOD in the preterm and term neonate. Chlorhexidine has been found to have no impact on antibiotic resistance, is inexpensive, and applicable to poorly equipped delivery sites.

OBJECTIVES

To determine the effectiveness of vaginal disinfection with chlorhexidine during labour in women who are colonized with GBS for preventing early-onset GBS infection in preterm and term neonates.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomized and quasi-randomized trials comparing vaginal disinfection with chlorhexidine (vaginal wash or gel/cream) versus placebo, or no treatment.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the trials for inclusion and risk of bias, extracted the data and checked them for accuracy.

MAIN RESULTS

We identified no new trials eligible for inclusion in this update. One study was moved from included to excluded studies from the previous version of the review. Four studies, including 1125 preterm and term infants, met the inclusion criteria and reported on at least one of the outcomes of interest. For the comparison chlorhexidine (vaginal wash or gel) versus placebo or no treatment, two studies (n = 987) were pooled. There was no statistically significant difference in early-onset GBS disease (sepsis and/or meningitis) comparing chlorhexidine (vaginal wash or gel/cream) versus placebo or no treatment; risk ratio (RR), 2.32 (95% confidence interval (CI) 0.34 to 15.63); I-squared (I²) = 0% or in GBS pneumonia; RR 0.35 (95% CI 0.01 to 8.6); test for heterogeneity not applicable. The outcome of colonization of the neonate with GBS was reported in three studies (n = 328); RR 0.64 (95% CI 0.40 to 1.01; there was substantial between-study heterogeneity (Chi² = 3.19; P = 0.20; I² = 37%). Maternal mild side effects (stinging or local irritation) (three trials, 1066 women) were more commonly seen in women treated with chlorhexidine (RR 8.50 (95% CI 1.60 to 45.28); there was no heterogeneity (Chi² = 0.01, df = 1 (P = 0.91); I² = 0%). No side effects were reported among the neonates.For the comparison chlorhexidine vaginal wash verus mechanical washing with placebo or no treatment (one study, n = 79), there was a significant reduction in neonatal colonization with GBS; RR 0.32 (95% CI 0.12 to 0.90). Tests for heterogeneity not applicable. There were no other significant results for this comparison.For the comparison chlorhexidine gel or cream versus placebo or no treatment, there were no statistically significant results for the outcomes reported on.The quality of the trials varied and the overall risk of bias was rated as unclear or high. The quality of the evidence using GRADE was very low for the outcomes of the comparison chlorhexidine (vaginal wash or gel/cream) versus placebo or no treatment. These outcomes included: early-onset GBS disease (sepsis and/or meningitis), GBS pneumonia, neonatal colonization with GBS, neonatal mortality due to early-onset GBS infection and adverse (mild) effects in the mother and the neonate.

AUTHORS' CONCLUSIONS

The quality of the four included trials varied as did the risk of bias and the quality of the evidence using GRADE was very low. Vaginal chlorhexidine was not associated with reductions in any of the primary outcomes of early-onset GBS disease (sepsis and/or meningitis) or GBS pneumonia. Vaginal chlorhexidine may reduce GBS colonization of neonates. The intervention was associated with an increased risk of maternal mild adverse effects. The review currently does not support the use of vaginal disinfection with chlorhexidine in labour for preventing early-onset disease. Results should be interpreted with caution as the methodological quality of the studies was poor. As early-onset GBS disease is a rare condition trials with very large sample sizes are needed to assess the effectiveness of vaginal chlorhexidine to reduce its occurrence. In the era of intrapartum antibiotic prophylaxis, such trials may be difficult to justify especially in developed countries.

Late-onset neonatal infections: incidences and pathogens in the era of antenatal antibiotics

Widespread use of intrapartum antimicrobial prophylaxis has significantly reduced the incidence of early-onset neonatal infection (EONI); however, little is known about the effects of increased maternal exposure to antibiotics on late-onset neonatal infection (LONI). This study aims to evaluate LONI epidemiology in our region after the application of French recommendations and to determine whether LONI-causing organisms and their antibiotic susceptibility are influenced by peripartum antibiotic exposure. We performed a prospective epidemiologic study of 139 confirmed and possible cases of bacterial LONI in patients treated with antibiotics for at least 5 days of the 22,458 infants born in our region in the year 2007. The overall incidence of LONI caused by all pathogens, Group B streptococcus (GBS) and Escherichia coli (E. coli) were 6.19, 0.36 and 2.72, respectively, per 1,000 live births. Our findings revealed three major types of LONI: E. coli-induced urinary tract infection (UTI) among term infants, coagulase negative Staphylococcus septicemia affecting preterm infants, and GBS infections with severe clinical presentation. Univariable analysis revealed that maternal antibiotic exposure was significantly associated with the risk of amoxicillin-resistant E. coli infection (p = 0.01). Postnatal antibiotic exposure was associated with an increased risk of E. coli LONI (p = 0.048). This link persisted upon multivariable analysis; however, no additional risk factors were identified for LONI caused by antibiotic-resistant E. coli.

CONCLUSION

Our findings confirm that despite the benefits of antenatal antibiotics, this treatment can increase the risk of antibiotic-resistant cases of LONI. National and international surveillance of LONI epidemiology is essential to assess benefits and potential negative consequences of perinatal antibiotic exposure.

[Prevention of early-onset group B Streptococcus infections. 2. Efficiency of the ANAES guidelines]

OBJECTIVES

To examine the efficiency on early-onset neonatal infections of the ANAES guidelines for early-onset infections prophylaxis, based on a systematic prenatal vaginal swab aiming Group B Streptococcus and/or infection risk factors during delivery.

PATIENTS AND METHODS

This is a retrospective cohort study of early-onset infections during a period of 28 months (6125 deliveries) compared to an earlier period (6141 deliveries).

RESULTS

The number of newborns admitted for suspected infection and the rate of sepsis have been unchanged. But the total number of infections has decreased (1.50 vs 2.02 %, p=0,024), without increase of the number of infections due to other germs such as Escherichia coli. Furthermore, a strategy based only on risk factors would not have allowed the early screening and treatment of 23 Streptococcus B infected newborns.

CONCLUSION

We have proved the efficiency of the protocol in terms of prevention of early-onset infections. However, it has led to a dramatic increase in the consumption of antibiotics, which is worrying concerning maternal and neonatal bacterial ecology.

Cost-effectiveness of universal prophylaxis in pregnancy with prior group B streptococci colonization

OBJECTIVE

To estimate the costs and outcomes of rescreening for group B streptococci (GBS) compared to universal treatment of term women with history of GBS colonization in a previous pregnancy.

STUDY DESIGN

A decision analysis model was used to compare costs and outcomes. Total cost included the costs of screening, intrapartum antibiotic prophylaxis (IAP), treatment for maternal anaphylaxis and death, evaluation of well infants whose mothers received IAP, and total costs for treatment of term neonatal early onset GBS sepsis.

RESULTS

When compared to screening and treating, universal treatment results in more women treated per GBS case prevented (155 versus 67) and prevents more cases of early onset GBS (1732 versus 1700) and neonatal deaths (52 versus 51) at a lower cost per case prevented ($8,805 versus $12,710).

CONCLUSION

Universal treatment of term pregnancies with a history of previous GBS colonization is more cost-effective than the strategy of screening and treating based on positive culture results.

Effect of intrapartum antibiotic prophylaxis against group B streptococcal infection on comparisons of rates of endometritis and urinary tract infection in multicenter surveillance

OBJECTIVE

To establish whether antibiotic prophylaxis against group B streptococcal infection may be a confounding factor in comparisons of rates of endometritis and urinary tract infection after vaginal delivery.

DESIGN

Prospective study.

SETTING

Maternity units at 48 hospitals in a regional surveillance network in France during 2001-2004.

METHODS

The maternity units used a common protocol to establish whether antibiotic prophylaxis was indicated. Risk factors for endometritis and urinary tract infections were evaluated using multiple logistic regression.

RESULTS

We analyzed 49,786 vaginal deliveries. The percentage of women receiving antibiotic prophylaxis varied widely and significantly among the maternity units (range, 4.4%-26.0%; median, 15.8%; 25th percentile, 12.1%; 75th percentile, 19.0%) (P < .001, by Mantel-Haenszel chi(2) test). The incidence rate of endometritis was significantly reduced from 0.25% to 0.11% by antibiotic prophylaxis (P = .001). There was a decrease in the incidence of urinary tract infection from 0.37% to 0.32%, but it was not statistically significant (P = .251).

CONCLUSIONS

A reduction in the incidence of endometritis was observed when intrapartum antibiotic prophylaxis against group B streptococcal infection was used. However, the proportion of women considered to be at risk of infection varied widely among institutions. Comparisons of rates of endometritis among maternity units, but not urinary tract infection rates, should take into account antibiotic prophylaxis as a significant confounding factor.

Application of the French guidelines for preventing neonatal group B streptococcal disease in a university hospital

This study evaluated the application of the French guidelines for prevention of neonatal group B streptococcus (GBS) infections. The prevalence of GBS vaginal carriage by pregnant women during the study period was 6%. Less than 50% of pregnant women testing positive for GBS were treated with at least two doses of antibiotics during labour, and most received only one dose or no antibiotics. In addition, several neonates were colonised or infected by GBS although their mothers were GBS-negative. These results are consistent with vaginal screening having a poor sensitivity, as suggested by the low prevalence of GBS carriage.

Group B Streptococcal Testing During Pregnancy: Survey of Postpartum Women and Audit of Current Prenatal Screening Practices

OBJECTIVE

Group B Streptococcus (GBS) can be transmitted from mother to child during delivery. At the time of the study, Nova Scotia guidelines for screening pregnant women for the presence of GBS recommended using one of two testing methods. The objective of this study was to determine the level of compliance with GBS testing recommendations and to determine women's knowledge of, attitudes towards, and beliefs about prenatal screening for this infection.

METHODS

All women who gave birth at a single tertiary care unit during a seven-week period were approached to participate in the study. Study participants were interviewed using a questionnaire to determine their knowledge of, attitudes towards, and beliefs about prenatal screening. Medical and laboratory records were reviewed in order to audit the prenatal screening practices.

RESULTS

A total of 24.5% of study participants were screened for the presence of GBS by culture of a vaginal-rectal swab taken at 35 37 weeks' gestation, and 75.5% were assessed using the risk factor approach. Of the women screened by culture, 19% were identified as needing antibiotic treatment compared with 25% of those screened by assessment of risk factors. Women were significantly less knowledgeable about GBS than about other specific infections, and they felt that the threat of GBS infection for their baby was lower than the threat of the other infections. However, many of these women were uncertain about the threat that GBS poses during pregnancy.

CONCLUSION

Screening for GBS by culture rather than by assessing risk factors would have reduced antibiotic usage in our study population by 23%. These results indicate that all women should be counselled regarding GBS infection and should be tested using the culture-based approach at 35 to 37 weeks' gestation.

[Group B streptococcus screening: a retrospective study in 1,674 pregnancies]

OBJECTIVE

To evaluate our clinical practice for Group B streptococcus (GBS) screening during pregnancy and antibiotic therapy during delivery.

MATERIAL AND METHODS

We performed a retrospective evaluation of our SBS screening protocol, by vaginal swab, for a period of two years, including 1,674 asymptotic patients. Intra partum antibiotic prophylaxis was administrated for GBS-positive women.

RESULTS

The rate of GBS carriage was 6.9%. Antibiotics were administrated for 79.3% patients with GBS-positive culture. Of these women only 39% had an interval greater than four hours between antibiotic injection and delivery. In the group of patients with positive GBS culture, no newborn was infected and only 5% were colonised. In the GBS-negative group with 1.3% of the newborns were GBS positive.

CONCLUSION

We were surprised by our low rate of GBS carriage and the non optimal application of antibiotics during labor. We reviewed our results with all our team and a prospective evaluation has been initiated.

The projected health benefits of maternal group B streptococcal vaccination in the era of chemoprophylaxis

While maternal antibiotic prophylaxis has greatly reduced early-onset group B streptococcal (GBS) disease in the United States, a GBS vaccine currently under development could potentially prevent additional GBS cases and preterm births. A decision analytic model was created to compare preventive strategies using adolescent, maternal (prenatal), or postpartum vaccination with selective chemoprophylactic strategies. The current practice of culture-based chemoprophylaxis was predicted to prevent 55% of early plus late-onset GBS infections. Maternal vaccination strategies were superior to current practice, preventing 68-69% of all GBS infections and 4% of very preterm births (<32 weeks gestation). The most effective adolescent vaccination strategy combined vaccination with culture-based chemoprophylaxis for all women and prevented 66% of all GBS infections. All other strategies were similar in efficacy to current practice or inferior. Maternal GBS vaccination is predicted to prevent more cases of neonatal GBS disease than current practice and would prevent approximately one in 25 very preterm births.

Vaginal chlorhexidine during labour to prevent early-onset neonatal group B streptococcal infection

BACKGROUND

Early-onset group B beta-hemolytic streptococcus (GBS) infection accounts for approximately 30% of neonatal infections, has a high mortality rate and is acquired through vertical transmission from colonized mothers. Several trials have demonstrated the efficacy of intrapartum chemoprophylaxis (IPC) for preventing early-onset disease (EOD). Vaginal disinfection with chlorhexidine during labour has been proposed as another strategy for preventing GBS EOD in the preterm and term neonate. Chlorhexidine has been found to have no impact on antibiotic resistance, is inexpensive, and applicable to poorly equipped delivery sites.

OBJECTIVES

To determine the effectiveness of vaginal disinfection with chlorhexidine during labour for preventing early-onset GBS infection in preterm and term neonates.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth trials register (October 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2003), MEDLINE (1966 to October 2003), EMBASE (1980 to March 2003), CINAHL (1982 to March 2003) and LILACS (1982 to September 2003).

SELECTION CRITERIA

Randomized and quasi-randomized trials comparing vaginal disinfection with chlorhexidine to placebo, or no treatment.

DATA COLLECTION AND ANALYSIS

We extracted information from the results sections of the included studies. We reported relative risk (RR) and risk difference (RD) with 95% confidence intervals (CI) for dichotomous outcomes. We calculated the number needed to treat (NNT) with 95% CIs when a statistically significant RD was found. We used a chi square test (chi2) and the I2 analysis to test for heterogeneity, and applied a fixed or random effects model accordingly.

MAIN RESULTS

Five studies, including approximately 2190 term and preterm infants, met the inclusion criteria and reported on at least one of the outcomes of interest for this systematic review. When all studies were combined there was a statistically significant (p = 0.005) reduction in colonisation (RR 0.72, 95% CI 0.56 to 0.91); RD -0.16 (95% CI -0.26 to -0.05); NNT 6 (95% CI 4 to 20). There was no statistically significant between-study heterogeneity. There was no statistically significant between-study heterogeneity both for RR (chi(2) = 3.21 [p = 0.2], I(2) = 37.8%) and for RD (chi(2) = 1.66 [p = 0.44], I(2) = 0%). There was no statistically significant reduction in EOD including GBS infection, GBS pneumonia, GBS meningitis or mortality.

REVIEWERS' CONCLUSIONS

Vaginal chlorhexidine resulted in a statistically significant reduction in GBS colonisation of neonates, but was not associated with reductions in other outcomes. The review currently does not support the use of vaginal disinfection with chlorhexidine in labour for preventing EOD. Results should be interpreted with caution as the methodological quality of the studies was poor.

A readers' guide to the interpretation of diagnostic test properties: clinical example of sepsis

BACKGROUND

One of the most challenging practical and daily problems in intensive care medicine is the interpretation of the results from diagnostic tests. In neonatology and pediatric intensive care the early diagnosis of potentially life-threatening infections is a particularly important issue.

FOCUS

A plethora of tests have been suggested to improve diagnostic decision making in the clinical setting of infection which is a clinical example used in this article. Several criteria that are critical to evidence-based appraisal of published data are often not adhered to during the study or in reporting. To enhance the critical appraisal on articles on diagnostic tests we discuss various measures of test accuracy: sensitivity, specificity, receiver operating characteristic curves, positive and negative predictive values, likelihood ratios, pretest probability, posttest probability, and diagnostic odds ratio.

CONCLUSIONS

We suggest the following minimal requirements for reporting on the diagnostic accuracy of tests: a plot of the raw data, multilevel likelihood ratios, the area under the receiver operating characteristic curve, and the cutoff yielding the highest discriminative ability. For critical appraisal it is mandatory to report confidence intervals for each of these measures. Moreover, to allow comparison to the readers' patient population authors should provide data on study population characteristics, in particular on the spectrum of diseases and illness severity.

Early-onset neonatal group B streptococcal infection: 2002 guidelines for prevention

In 1996, the Centers for Disease Control and Prevention (CDC) and relevant professional organizations jointly released guidelines for prevention of early-onset neonatal group B streptococcal infections. The guidelines recommended that all obstetric providers and institutions providing intrapartum services follow one of two strategies. This year, on the basis of multistate surveillance data collected since prevention strategies were initiated, the CDC has released revised prevention recommendations. This article reviews the new guidelines and discusses clinical implications for practice in a variety of settings.

Perinatal screening for group B streptococci: cost-benefit analysis of rapid polymerase chain reaction

OBJECTIVE

To evaluate the costs and benefits of a group B streptococci screening strategy using a new, rapid polymerase chain reaction test in a hypothetical cohort of expectant mothers in the United States.

DESIGN

Cost-benefit analysis using the human capital method. We developed a decision model to analyze the costs and benefits of a hypothetical group B streptococci screening strategy using a new, rapid polymerase chain reaction test as compared with the currently recommended group B streptococci screening guidelines-prenatal culture performed at 35 to 37 weeks or risk-factor-based strategy with subsequent intrapartum treatment of the expectant mothers with antibiotics to prevent early-onset group B streptococcal infections in their infants.

PARTICIPANTS

A hypothetical cohort of pregnant women and their newborns.

INTERVENTIONS

Screening strategies for group B streptococci using the new polymerase chain reaction technique, the 35- to 37-week culture, or maternal risk factors.

OUTCOME MEASURES

Infant infections averted, infant deaths, infant disabilities, costs, and societal benefits of healthy infants.

RESULTS

A screening strategy using the new polymerase chain reaction test generates a net benefit of $7 per birth when compared with the maternal risk-factor strategy. For every 1 million births, 80 700 more women would receive antibiotics, 884 fewer infants would become infected with early-onset group B streptococci, and 23 infants would be saved from death or disability. The polymerase chain reaction-based strategy generates a net benefit of $6 per birth when compared with the 35- to 37-week prenatal culture strategy and results in fewer maternal courses of antibiotics (64 080 per million births), fewer perinatal infections with early-onset group B streptococci (218/million), and a reduction in 6 infant deaths and severe infant disability per million births. The benefits hold over a wide range of assumptions regarding key factors in the analysis.

CONCLUSIONS

Although additional clinical trials are needed to establish the accuracy of this new polymerase chain reaction test, initial studies suggest that strategies using this test will be superior to the other 2 strategies. Using the rapid polymerase chain reaction test becomes less attractive as the cost of the test increases. The test's greatest strengths lie in its ability to identify women and infants at risk at the time of labor, thereby decreasing the number of false-positives and false-negatives seen with the other 2 strategies and allowing for more accurate and effective intrapartum prophylaxis.

Choosing a strategy to prevent neonatal early-onset group B streptococcal sepsis: economic evaluation

OBJECTIVE

To determine the most appropriate strategy to prevent neonatal streptococcal sepsis in a setting with a low incidence of the disease.

DESIGN

Decision analysis and economic evaluation.

SETTING

Geneva University Hospitals, Switzerland.

POPULATION

Pregnant women at 35-37 weeks of gestation and in labour.

METHODS

Local data and data from the literature were used in a decision analysis to compare the current policy of antibiotic administration at Geneva University Hospitals with the recommended preventive strategies.

MAIN OUTCOME MEASURES

Number of episodes of sepsis averted; cost and number needed to treat to prevent one episode of sepsis; and proportion of women receiving antibiotics during labour.

RESULTS

Compared with the current policy, the risk factors strategy would prevent 69 streptococcal sepsis per million deliveries and the screening strategy would prevent 102 cases of sepsis per million deliveries. Cost per averted sepsis case would be 60 pounds, 700 and 473 pounds, 600, respectively. The number needed to treat to prevent one sepsis would be 1,087 with a risk factors strategy and 1,029 with a screening strategy. Preventive strategies would increase the proportion of women receiving antibiotics during labour from 6% with the current policy, to 13.5% and 16.5% respectively.

CONCLUSIONS

Preventive strategies are more effective than the current policy, but imply increased hospital costs and a notable increase in the proportion of women receiving antibiotics during labour, which may be unjustified in a low incidence setting.

Evidence-based health care coverage for children: proceed with caution

Making health care coverage depend on the existence of valid, applicable research data and positive cost-effectiveness analyses, as managed care contracts are beginning to do, is particularly problematic for children. Because of research challenges specific to children, there are relatively few pediatric data and analyses required under such evidence-based coverage standards. It is too soon to expect major increases from federal efforts to stimulate pediatric health care research. But absence of requisite evidence would entitle a managed care organization or other decision maker to deny coverage on the basis of unproven, negative assumptions about an intervention. In general, population-based evidence is an incomplete basis for decisions on coverage for individual patients. Cost-effectiveness analyses are not standardized and may be biased. Purchasers of managed care and policy makers should understand the limits of evidence-based coverage standards. Other uses of evidence may contribute more to systemic improvements of health care.

Group B streptococcal (GBS) disease screening and treatment during pregnancy: nurse-midwives' consistency with 1996 CDC recommendations

OBJECTIVE

In 1998, the screening and treatment practices of certified nurse-midwives (CNMs) for group B streptococcal (GBS) infection during pregnancy were studied and evaluated for their consistency with the 1996 perinatal GBS prevention guidelines of the Centers for Disease Control and Prevention (CDC).

METHODOLOGY

Five hundred thirty-nine surveys were completed by CNMs attending the 1998 American College of Nurse-Midwives' Convention. Of these, 502 (94.7%) reported a practice policy for GBS prophylaxis.

RESULTS

The Culture-Based Approach was used by 66.7% and the Obstetrical Risk Factor Approach by 28%. Most (69%) reported using multiple culture sites, most commonly the proximal vagina and anorectal area (33.2%), followed by the distal vagina and anorectal area (26.7%), and the anorectal area and proximal and distal vagina (7.1%). Most CNMs (92.5%) reported treating GBS intrapartally, with penicillin the most frequently reported antimicrobial (55.0%) used, and most (94.2%) reporting treatment through labor until birth.

CONCLUSION

Overall, GBS prophylaxis practices among survey respondents comply with 1996 CDC recommendations; however, GBS screening practices show room for improvement and the need for continuing education that emphasizes the CDC guidelines, updates as they become available, and other new literature about the topic. In addition, heightened awareness among all perinatal providers is needed with respect to CDC guidelines, especially as they pertain to variations in culture sites, identification of risk categories, and the selection of appropriate antimicrobial treatment agents.