Maternal and neonatal infection rates with three different protocols for prevention of group B streptococcal disease

Postpartum endometritis after uterine cleaning versus no cleaning in cesarean sections: Randomized clinical trial

AIM

The aim of the study was to compare the rates of postpartum endometritis due to uterine cleaning and no cleaning in patients delivered by elective cesarean section.

METHODS

This was a randomized clinical trial conducted at the Obstetrics and Gynecology Department, Suez Canal University Hospital, Ismailia, from June 2019 to November 2019. We recruited patients undergoing cesarean delivery aged 18-45 years with singleton pregnancy, intact membranes, either first or repeated delivery, without labor pains. Patients were allocated into two groups, uterine cleaning (336 patients) and no cleaning (312 patients). The main outcome measure was the occurrence of postpartum endometritis.

RESULTS

Both groups were matched in their demographic characters. Twelve patients (3.6%) developed endometritis in the cleaning group versus one patient (0.3%) in the other one. Estimated blood loss was 754.35 ± 247.13 and 730.36 ± 232.77 for the cleaning and no cleaning groups, respectively, with a P value of 0.201. Septic wound infection (21 patients, 6.3%) was predominant in the cleaning group.

CONCLUSION

Uterine cleaning after delivery of the placenta during CS can be omitted as a surgical step during the operation. It was associated with increased rates of postpartum endometritis and blood loss.

Screening-based and Risk-based Strategy for the Prevention of Early-onset Group B Streptococcus/Non-group B Streptococcus Sepsis in the Neonate: A Systematic Review and Meta-analysis

BACKGROUND

Screening-based and risk-based strategies are the 2 strategies for preventing group B streptococcus (GBS) diseases in neonates. We aimed to compare the effects of these 2 strategies in reducing the incidence of early-onset GBS sepsis (GBS-EOS) and their effects on the incidence of non-GBS sepsis.

METHODS

PubMed, Embase, Web of Science and The Cochrane Central Register of Controlled Trials were searched for the period from January 1, 1996, to December 31, 2018. Randomized controlled trials and cohort studies that compared the effects of risk-based and screening-based strategies were eligible for the meta-analysis. The I statistic was used for assessing the statistical heterogeneity across studies. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated using the random effects model.

RESULTS

There were 18 cohort studies comparing the incidence of GBS-EOS between the 2 strategies, involving a total of 604,869 newborns and 791 GBS-EOS cases. The heterogeneity across studies was moderate (I = 45%), and the pooled analysis yielded a 55% decreased risk of GBS-EOS for screening-based versus risk-based strategy (RR = 0.45; 95% CI: 0.34-0.59). For total early onset non-GBS sepsis (non-GBS-EOS), 7 studies with low heterogeneity (I = 18%) had a pooled RR of 0.91 (95% CI: 0.74-1.11), whereas for ampicillin resistant Escherichia coli-EOS, a subgroup of non-GBS-EOS, 3 studies with very low heterogeneity (I = 0%) had a pooled RR of 1.28 (95% CI: 0.74-2.21) for screening-based strategy compared with risk-based strategy.

CONCLUSIONS

Compared with risk-based strategy, screening-based prophylaxis was associated with a reduced risk of GBS-EOS.

Evaluation of an in-house real-time polymerase chain reaction method to identify group B streptococcus colonization in pregnancy

AIM

The aim of this study was to evaluate the performance of in-house real-time polymerase chain reaction (qPCR) in detecting group B streptococcus (GBS) colonization compared with the standard culture method in a cohort of pregnant women.

MATERIAL AND METHODS

A total of 134 rectovaginal swabs were collected from 125 pregnant women, of whom 108 were known carriers or presented with preterm prelabor rupture of membranes. The swabs were placed in Standard Methods Broth (Todd-Hewitt broth supplemented with 6 μg/mL gentamicin and 15 μg/mL nalidixic acid) for culture identification of GBS. An in-house qPCR was also performed from the broth and after overnight incubation of the broth.

RESULTS

The detection rate of GBS in this cohort was 30.6% and 50.7% using standard culture method and qPCR, respectively. GBS-specific qPCR assay gave sensitivities of 97.6% and 100%, specificities of 73.1% and 71.0%, and negative predictive values of 98.6% and 100% from direct specimen and from broth after overnight incubation, respectively.

CONCLUSIONS

The in-house qPCR test has high sensitivity in detecting GBS colonization. The high negative predictive value helps to avoid unnecessary use of antibiotics in uncolonized women.

[Epidemiology and management of intrapartum infections in the maternity ward of Ouémé-Plateau county hospital in Benin]

Introduction

La présente étude avait pour objectif de mesurer l'ampleur des infections du per-partum à la maternité du Centre Hospitalier Départemental de l'Ouémé-Plateau d'analyser les conditions de survenue et de prise en charge dans la perspective de l'amélioration des soins et services maternels et néonataux.

Méthodes

Une étude descriptive et analytique a été conduite de Août 2009 à Février 2010 et a impliqué 110 mères victimes d'infections du per-partum; elles ont été soumises à un questionnaire durant tout leur séjour hospitalier; des observations des pratiques de prise en charge des prestataires de soins ont été menées et des registres et autres supports de données sanitaires ont été exploités. L'analyse des données a été effectuée à l'aide du logiciel Epi Info 6.4 dans sa version française.

Résultats

L'incidence des infections du per-partum était de 5,9 pour 100 accouchements (110/ 1875); les types d'infections les plus incriminés étaient les endométrites (27,3%), les chorioamniotites (18,2%), les infections du site opératoire (12,7%) et les infections urinaires (2,7%). Les examens cliniques ont été relativement acceptables. En revanche, les examens biologiques ont été très insuffisants expliquant l'imprécision importante au niveau des diagnostics. L'antibiothérapie a été instaurée systématiquement. Le taux de mortinaissance était de 25,6% et les enfants de petit poids représentaient 23,2%.

Conclusion

L'incidence des infections du per-partum dans la présente étude était assez élevée. Des efforts de préventions et de dépistage de ces infections sont nécessaire afin d'améliorer la qualité des soins

Peripartum bacteremia in the era of group B streptococcus prophylaxis

OBJECTIVE

To define the microbial epidemiology and clinical risk factors associated with peripartum bacteremia in the era of group B streptococcus prophylaxis.

METHODS

We identified all cases of maternal bacteremia occurring during the peripartum time period (defined as from 7 days before delivery until 30 days after delivery) in a large maternity center from 2000 to 2008. Chart review was performed to determine the clinical factors associated with bacteremia.

RESULTS

During the study period, blood cultures were obtained from 1,295 febrile peripartum women (1.6% of all parturients); 172 of 1,295 febrile peripartum women (13.3%) had bacteremia (2.2 cases per 1,000 deliveries) with 194 microbial isolates and 1 yeast. The most frequent bacterial isolates were Escherichia coli (35.9%), enterococci (23.6%), and anaerobic species (9.2%); group B streptococcus was isolated in only eight cases (4.1%). Clinical diagnoses among infected women included endometritis (56%), chorioamnionitis (21%), and urosepsis (8%). Among women with endometritis, 77% underwent cesarean delivery (compared with vaginal delivery; relative risk [RR] 10.85, 95% confidence interval [CI] 6.75-17.45) and 39% delivered at less than 37 weeks of gestation (compared with 37 weeks or more; RR 3.21, 95% CI 2.42-4.25). Severe maternal complications of bacteremia were noted; six women required intensive care unit admission, five women had development of ileus, and one death occurred because of urosepsis.

CONCLUSION

In the era of group B streptococcus prophylaxis, E coli and enterococci are the most frequent bacteria isolated in peripartum bacteremia. Group B streptococcus accounted for only 4% of cases.

LEVEL OF EVIDENCE

III.

Preventing the broad spectrum of perinatal morbidity and mortality through group B streptococcal vaccination

The development of a group B streptococcal (GBS) glycoconjugate vaccine and its upcoming evaluation in a phase 3 trial in pregnant women highlight the importance of defining the anticipated impact of GBS vaccination upon the broad spectrum of GBS-related perinatal morbidity and mortality. We present the specific pregnancy-associated and neonatal conditions attributable, at least in part, to GBS in high and lower income countries. We offer a rationale to support our contention that implementation of GBS glycoconjugate immunization during pregnancy will reduce the global burden of GBS-related morbidity and mortality in pregnant women and their infants.

Screening for group B Streptococcus in pregnant women: a systematic review and meta-analysis

Infection with Group B Streptococcus (GBS) is considered an important public health problem. It is associated with: Neonatal sepsis, meningitis, pneumonia, neonatal death, septic abortion, chorioamnionitis, endometritis and other perinatal infections. The aim of this study was to determine the best screening strategy for GBS in pregnant women. For this a systematic review and meta-analysis were carried out in the Nursing Department of the Federal University of São Paulo, Cochrane Center, Brazil. Sources used were, EMBASE, LILACS, Medline, list of references, personal communication and the Cochrane library. The criterion for the selection of the studies was; studies which analyze some type of screening for GBS in pregnant women. Independent of the comparator, all analyses were in favor of a universal screening program for reducing the incidence of neonatal sepsis. The evidence obtained in this study suggests that the strategy of universal screening of pregnant women associated with the use of prophylactic antibiotics is safe and effective.

Universal screening vs. risk-based strategy for prevention of early-onset neonatal Group-B streptococcal disease

OBJECTIVE

To evaluate the difference between universal screening and risk-based strategies in the prevention of early-onset Group-B streptococcal (EOGBS) disease.

SUBJECTS

Cases of EOGBS disease from 2003 to 2009 were identified by a search of the microbiology laboratory's computerized database.

INTERVENTIONS

Maternal screening for Group-B Streptococci was done for all pregnant women by taking rectovaginal swabs and urine culture at 35-37 weeks of gestation and for all high-risk cases at the time of presentation.

RESULTS

From 2003 to 2009, a total of 87,260 live births were recorded, 1948 neonates were very low-birth weight. We reviewed labor and delivery records for 1268 live births randomly sampled from total live births. Forty-five cases of EOGBS disease were identified during the period of study (overall incidence of 0.51 cases per 1000 live births).

Risk factors for endometritis after low transverse cesarean delivery

OBJECTIVE

To determine independent risk factors for endometritis after low transverse cesarean delivery.

STUDY DESIGN

We performed a retrospective case-control study during the period from July 1999 through June 2001 in a large tertiary care academic hospital. Endometritis was defined as fever beginning more than 24 hours or continuing for at least 24 hours after delivery plus fundal tenderness in the absence of other causes for fever. Independent risk factors for endometritis were determined by means of multivariable logistic regression. A fractional polynomial method was used to examine risk of endometritis associated with the continuous variable, duration of rupture of membranes.

RESULTS

Endometritis was identified in 124 (7.7%) of 1,605 women within 30 days after low transverse cesarean delivery. Independent risk factors for endometritis included age (odds ratio [OR] for each additional year, 0.93 [corrected] [95% confidence interval {CI}, 0.90-0.97]) and anemia or perioperative blood transfusion (OR, 2.18 [CI, 1.30-3.68]). Risk of endometritis was marginally associated with a proxy for low socioeconomic status, lack of private health insurance (OR, 1.72 [CI, 0.99-3.00]); with amniotomy (OR, 1.69 [CI, 0.97-2.95]); and with longer duration of rupture of membranes.

CONCLUSION

Risk of endometritis was independently associated with younger age and anemia and was marginally associated with lack of private health insurance and amniotomy. The odds of endometritis increased approximately 1.7-fold within 1 hour after rupture of membranes, but increased duration of rupture was only marginally associated with increased risk. Knowledge of these risk factors can guide selective use of prophylactic antibiotics during labor and heighten awareness of the risk in subgroups at highest risk of infection.

Streptococcal Infections

The streptococci are a large heterogeneous group of gram-positive spherically shaped bacteria widely distributed in nature. They include some of the most important agents of human disease as well as members of the normal human flora. Some streptococci have been associated mainly with disease in animals, while others have been domesticated and used for the culture of buttermilk, yogurt, and certain cheeses. Those known to cause human disease comprise two broad categories: First are the pyogenic streptococci, including the familiar β-hemolytic streptococci and the pneumococcus. These organisms are not generally part of the normal flora but cause acute, often severe, infections in normal hosts. Second are the more diverse enteric and oral streptococci, which are nearly always part of the normal flora and which are more frequently associated with opportunistic infections.

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.

The Prevention of Early-Onset Neonatal Group B Streptococcal Disease

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

Intrapartum antibiotic prophylaxis and early-onset neonatal sepsis patterns

Objective: To compare the relative effects of intrapartum antibiotic prophylaxis regimens on patterns of early-onset neonatal sepsis.

Methods: We performed an historical cohort study of 17 187 infants born at our center from September 1993 to February 2000. A risk-based strategy was employed prior to July 1996 and a screening-based strategy was utilized thereafter. Ampicillin was utilized prior to March 1995 and penicillin was used thereafter.

Results: There were 75 cases of neonatal sepsis, 34 (4.10/1000) in the risk-based era and 41 (4.63/1000) in the screening-based era (p = 0.62). There were fewer ampicillin-resistant isolates during the risk-based than the screening-based era (32 versus 61%; p = 0.014). The only significant change in organism-specific sepsis rates was an increase in the rate of infection caused by coagulase-negative staphylococci in the screening-based era (0.36 versus 1.46/1000; p = 0.018), but 75% of infants infected with these organisms were not exposed to ß-lactam antibiotics within 72 h prior to delivery. For the risk- and screening-based eras, respectively, the rates of Gram-negative sepsis (1.21 versus 1.46/1000; p = 0.65) and the proportions of Gram-negative pathogens that were ampicillin-resistant (70 versus 77%; p = 1.0) were similar. The drug employed for prophylaxis did not appear to affect the pattern of sepsis cases.

Conclusion: In our patient population, coagulase-negative staphylococci have become the most common cause of early-onset neonatal sepsis. The cause of this shift in pathogen prevalence is uncertain and seemingly unrelated to intrapartum antibiotic exposure.

Amniotic infection syndrome: nosology and reproducibility of placental reaction patterns

Clinically responsive placental examination seeks to provide useful information regarding the etiology, prognosis, and recurrence risk of pregnancy disorders. The purpose of this study was to assemble and validate a complete set of the placental reaction patterns seen with amniotic fluid infection in the hope that this might provide a standardized diagnostic framework useful for practicing pathologists. Study cases (14 with amniotic fluid infection, 6 controls) were reviewed blindly by six pathologists after agreement on a standard set of diagnostic criteria. After analysis of initial results, criteria were refined and a second, overlapping set of cases were reviewed. Majority vote served as the gold standard. Grading and staging of maternal and fetal inflammatory responses was found to be more reproducible using a two- versus three-tiered grading system than a three- versus five-tiered staging system (overall agreement 81% vs. 71%). Sensitivity, specificity, and efficiency for individual observations ranged from 67-100% (24/30 > 90%). Reproducibility was measured by unweighted kappa values and interpreted as follows: < 0.2, poor; 0.2-0.6, fair/moderate; > 0.6, substantial. Kappa values for the 12 lesions evaluated in 20 cases by the six pathologists were: acute chorioamnionitis/maternal inflammatory response (any, 0.93; severe 0.76; advanced stage, 0.49); chronic (subacute) chorioamnionitis (0.25); acute chorioamnionitis/fetal inflammatory response (any, 0.90; severe, 0.55; advanced stage, 0.52); chorionic vessel thrombi (0.37); peripheral funisitis (0.84); acute villitis (0.90); acute intervillositis/intervillous abscesses (0.65), and decidual plasma cells (0.30). Adoption of this clearly defined, clinically relevant, and pathologically reproducible terminology could enhance clinicopathologic correlation and provide a framework for future clinical research.

Neonatal early-onset group B streptococcal disease in the era of intrapartum chemoprophylaxis: residual problems

OBJECTIVE

To identify limitations of current strategies for intrapartum prophylaxis of neonatal early-onset group B streptococcal infection.

METHODS

Retrospective review of infants with culture-proven early-onset group B streptococcal infection admitted to two nurseries and their mothers from July 1992, when ACOG and AAP guidelines for intrapartum prophylaxis were first issued, through December 2001. Information was recorded regarding clinical risk factors for early-onset group B streptococcal infection, collection and processing of specimens to assess maternal colonization, delivery of prophylaxis, duration of hospitalization before delivery, and outcome.

RESULTS

Among 92 infants with early-onset group B streptococcal infection admitted from 23 institutions, 68 had received no intrapartum prophylaxis. Of these 68 who received no prophylaxis, 34 had identifiable risk factors before delivery (32 clinical, two positive maternal culture), while 34 had no risk factors. Prenatal culture for group B streptococcal colonization was performed in 22 of these women. Of the 18 cultures that were negative for group B streptococcus, 15 were obtained using suboptimal culture technique or were collected more than 6 weeks before delivery. Of the 68 with no prophylaxis, 14 required extracorporeal membrane oxygenation and three died. Of the 24 who received some intrapartum prophylaxis, nine had received >/=two doses for >/=4 hours immediately before delivery. Among the 24 receiving some intrapartum prophylaxis, two required extracorporeal membrane oxygenation and one died. No deaths occurred in those who received >4 hours of prophylaxis, although one such infant required extracorporeal membrane oxygenation. After the CDC guidelines were issued in May 1996, there was a decrease both in the number of cases of early-onset group B streptococcal infection (56 versus 36) as well as in the number with clinical risk factors but no intrapartum prophylaxis (24/56 (43%) versus 5/28 (18%)).

CONCLUSIONS

The use of clinical risk factors alone will inevitably result in missed opportunity for intrapartum antibiotic prophylaxis. With maternal screening, false-negative results will be reduced but not necessarily eliminated by assuring that specimens are obtained from proper sites using selective media within 6 weeks of delivery. Better strategies are needed to assure timely administration when prophylaxis is indicated. The nine neonates with early-onset group B streptococcal infection despite intrapartum antibiotics for the recommended duration illustrate that disease may occur even when guidelines are implemented appropriately.

Early-onset group B streptococcal infection after a combined maternal and neonatal group B streptococcal chemoprophylaxis strategy

OBJECTIVE

In January 1995, a combined maternal and neonatal protocol for prevention of early-onset group B streptococcal (GBS) infection was implemented that consisted of a risk factor-based approach for maternal intrapartum chemoprophylaxis using ampicillin combined with a single intramuscular dose of penicillin given to all newborns within 1 hour of delivery. The objective of this study was to review the cases of early-onset GBS infections that occurred from 1995 to 1999 to identify factors associated with their continued occurrence despite implementation of a GBS chemoprophylaxis protocol.

METHODS

Infants <or=72 hours of age with early-onset GBS infection born at Parkland Memorial Hospital in Dallas from January 1995 to December 1999 were identified through a prospective laboratory-based surveillance system. Maternal and infant medical records were reviewed for clinical and demographic data.

RESULTS

There were 32 cases (0.47/1000 live births) of early-onset GBS infection for the 5-year period. This represented a 76% reduction compared with the rate from 1986 to 1994 (1.95/1000), when there was no protocol for GBS chemoprophylaxis. Thirteen cases (41%) did not have any identifiable maternal risk factor. Of the 19 cases (59%) with risk factors, maternal intrapartum fever was the most frequent (15 [79%]), followed by prematurity (6 [32%]) and prolonged rupture of membranes (6 [32%]). Among the 19 mothers with risk factors, 15 (79%) mothers received intrapartum chemoprophylaxis, and 12 (80%) of the 15 mothers had intrapartum fever. Only 33% of mothers with risk factors received >or=2 doses of intrapartum chemoprophylaxis, and among those with intrapartum fever, 25% received >or=2 doses. None of the 32 infants with early-onset GBS infection received the combination of intrapartum ampicillin and postnatal penicillin.

CONCLUSIONS

A combined obstetric and neonatal chemoprophylaxis protocol significantly reduced early-onset GBS infection. Maternal intrapartum fever was the most frequent risk factor associated with failure of chemoprophylaxis.

Screening strategies for group B streptococcus in the third trimester of pregnancy

PURPOSE

To identify the best screening protocol to prevent neonatal group B streptococcal (GBS) sepsis through literature review.

DATA SOURCES

Selected research articles, texts, and Internet sources.

CONCLUSIONS

Centers for Disease Control and Prevention (CDC), American Academy of Pediatrics (AAP), American College of Obstetricians and Gynecologists (ACOG), and American College of Nurse Midwives (ACNM) have issued guidelines describing methods to identify pregnant women at risk of intrapartum transmission of GBS to their babies. Studies have been conducted to discover the superiority of one prevention method over the other but no consensus has been reached.

IMPLICATIONS FOR PRACTICE

Before widely used prevention methods, approximately 8,000 babies each year became infected with GBS; of those, 400 died and many survivors suffered life-long sequelae. Adoption of an appropriate protocol can prevent transmission of GBS from a colonized mother to her infant. Clinicians should implement either universal culture-based or risk factor-based screening guidelines for prenatal diagnosis and intrapartum prophylaxis of GBS disease.

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.

A population-based comparison of strategies to prevent early-onset group B streptococcal disease in neonates

BACKGROUND

Guidelines issued in 1996 in the United States recommend either screening of pregnant women for group B streptococcal colonization by means of cultures (screening approach) or assessing clinical risk factors (risk-based approach) to identify candidates for intrapartum antibiotic prophylaxis.

METHODS

In a multistate retrospective cohort study, we compared the effectiveness of the screening and risk-based approaches in preventing early-onset group B streptococcal disease (in infants less than seven days old). We studied a stratified random sample of the 629,912 live births in 1998 and 1999 in eight geographical areas where there was active surveillance for group B streptococcal infection, including all births in which the neonate had early-onset disease. Women with no documented culture for group B streptococcus were considered to have been cared for according to the risk-based approach.

RESULTS

We studied 5144 births, including 312 in which the newborn had early-onset group B streptococcal disease. Antenatal screening was documented for 52 percent of the mothers. The risk of early-onset disease was significantly lower among the infants of screened women than among those in the risk-based group (adjusted relative risk, 0.46; 95 percent confidence interval, 0.36 to 0.60). Because women whose providers had no strategy for prophylaxis may have been misclassified in the risk-based group, we excluded all women with risk factors and adequate time for prophylaxis who did not receive antibiotics. The adjusted relative risk of early-onset disease associated with the screening approach in this secondary analysis was similar--0.48 (95 percent confidence interval, 0.37 to 0.63).

CONCLUSIONS

Routine screening for group B streptococcus during pregnancy prevents more cases of early-onset disease than the risk-based approach. Recommendations that endorse both strategies as equivalent warrant reconsideration.

Early-onset neonatal group B streptococcal infections in New Zealand 1998-1999

OBJECTIVE

To determine in New Zealand infants the attack rates, risk factors, preventive policies, strain serotype and antibiotic susceptibilities of early-onset neonatal group B streptococcus (GBS) infection.

METHOD

A 2-year prospective active surveillance study was conducted in New Zealand's 19 neonatal units. Cases had to present within 48 h of delivery, be unwell, possess abnormal haematological indices and have GBS isolated from sterile sites.

RESULTS

Of the 112 402 infants born in New Zealand during 1998-1999, 56 had early-onset GBS infection, an attack rate of 0.5 per 1000 live births (95% confidence interval [CI] 0.38, 0.65). Seven had meningitis and there was one death (case fatality rate of 1.8%; upper 95% CI 9.5%). Univariate analysis identified young maternal age, parity, preterm labour, prolonged membrane rupture, maternal fever and assisted delivery as risk factors. Preventive policies for GBS were reported by 14 (74%) obstetric centres associated with neonatal units. Of the 56 cases, five (9%) were born to mothers receiving intrapartum antibiotics, 32 (57%) had mothers with risk factors but were not treated with antibiotics, and 19 (34%) were born to mothers without identifiable risk factors for GBS prevention. Serotypes Ia and III predominated, while two isolates were resistant to erythromycin and/or clindamycin.

CONCLUSIONS

Rates of early-onset GBS infection are similar to other countries following the introduction of prevention policies. Further reductions are possible with full implementation of these guidelines. Meanwhile, emergence of antibiotic resistance complicates the management of women with penicillin allergy. Vaccine development therefore remains a priority.

Group B streptococcal infections in newborns

Group B streptococcus (GBS) is the most common cause of neonatal infection in North America and is associated with morbidity and mortality. Prompt recognition and treatment of the infection is imperative. Diagnostic tests and treatment options vary, without clear research-based recommendations. Future trends should focus on GBS infection as a public health issue, with an emphasis on prevention.

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.

Rapid detection of group B streptococci in pregnant women at delivery

BACKGROUND

Group B streptococcal infections are an important cause of neonatal morbidity and mortality. A rapid method for the detection of this organism in pregnant women at the time of delivery is needed to allow early treatment of neonates.

METHODS

We studied the efficacy of two polymerase-chain-reaction (PCR) assays for routine screening of pregnant women for group B streptococci at the time of delivery. We obtained anal, vaginal, and combined vaginal and anal specimens from 112 pregnant women; in 57 women, specimens were obtained before and after the rupture of the amniotic membranes. The specimens were tested for group B streptococci by culture in a standard selective broth medium, with a conventional PCR assay, and with a new fluorogenic PCR assay.

RESULTS

Among the 112 women, the results of the culture of the combined vaginal and anal specimens were positive for group B streptococci in 33 women (29.5 percent). The two PCR assays detected group B streptococcal colonization in specimens from 32 of these 33 women: the one negative PCR result was in a sample obtained after the rupture of membranes. As compared with the culture results, the sensitivity of both PCR assays was 97.0 percent and the negative predictive value was 98.8 percent. Both the specificity and the positive predictive value of the two PCR assays were 100 percent. The length of time required to obtain results was 30 to 45 minutes for the new PCR assay, 100 minutes for the conventional PCR assay, and at least 36 hours for culture.

CONCLUSIONS

Colonization with group B streptococci can be identified rapidly and reliably by a PCR assay in pregnant women in labor both before and after the rupture of membranes.

Prevention of early-onset invasive neonatal group B streptococcal disease in a private hospital setting: the superiority of culture-based protocols

OBJECTIVE

In a large private tertiary care hospital we compared the two different approaches to group B streptococcal screening and intrapartum chemoprophylaxis suggested by The American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, and the Centers for Disease Control and Prevention: risk factor-based protocol and culture-based protocol.

STUDY DESIGN

A 2-year baseline period was followed by sequential prospective observational studies of the impacts of two different group B streptococcal management protocols, 3 years with the risk-based approach and 2 years with the culture-based approach of universal screening at 35 to 37 weeks' gestation.

RESULTS

During the baseline period the rate of early-onset group B streptococcal infection was 1. 1 cases per 1000 births (n = 8 cases per 6829 births). With the risk-based strategy the rate was also 1.1 cases per 1000 births (15 cases/13,270 births). After we switched to the culture-based protocol for 2 years, there were no cases of early-onset group B streptococcal infections among 9304 births (P =.001; chi(2) = 10.9). There were no increases in other early-onset infections or in antibiotic resistance.

CONCLUSIONS

In our setting, which included good prenatal care and good communication between laboratories and the hospital, the approach based on maternal culture at 35 to 37 weeks' gestation and treatment during labor of all patients with positive results significantly reduced early-onset group B streptococcal infections without increasing infections from resistant organisms.

Chemoprophylaxis of early-onset group B streptococcal disease in 1999

The evolution of the guidelines for selective intrapartum chemoprophylaxis (SIC) of group B streptococcal early-onset disease is reviewed here. To assess the benefits of the risk-based and culture-based strategies for prevention, observational studies since 1996 are summarized. The effect of chorioamnionitis on group B streptococcal early-onset disease, despite SIC, is emphasized. Optimal management remains controversial, and alternative strategies for the selection of women for chemoprophylaxis and for the management of infants are discussed.

Group B streptococcal disease in the era of intrapartum antibiotic prophylaxis

BACKGROUND

Group B streptococcal infections are a leading cause of neonatal mortality, and they also affect pregnant women and the elderly. Many cases of the disease in newborns can be prevented by the administration of prophylactic intrapartum antibiotics. In the 1990s, prevention efforts increased. In 1996, consensus guidelines recommended use of either a risk-based or a screening-based approach to identify candidates for intrapartum antibiotics. To assess the effects of the preventive efforts, we analyzed trends in the incidence of group B streptococcal disease from 1993 to 1998.

METHODS

Active, population-based surveillance was conducted in selected counties of eight states. A case was defined by the isolation of group B streptococci from a normally sterile site. Census and live-birth data were used to calculate the race-specific incidence of disease; national projections were adjusted for race.

RESULTS

Disease in infants less than seven days old accounted for 20 percent of all 7867 group B streptococcal infections. The incidence of early-onset neonatal infections decreased by 65 percent, from 1.7 per 1000 live births in 1993 to 0.6 per 1000 in 1998. The excess incidence of early-onset disease in black infants, as compared with white infants, decreased by 75 percent. Projecting our findings to the entire United States, we estimate that 3900 early-onset infections and 200 neonatal deaths were prevented in 1998 by the use of intrapartum antibiotics. Among pregnant girls and women, the incidence of invasive group B streptococcal disease declined by 21 percent. The incidence among nonpregnant adults did not decline.

CONCLUSIONS

Over a six-year period, there has been a substantial decline in the incidence of group B streptococcal disease in newborns, including a major reduction in the excess incidence of these infections in black infants. These improvements coincide with the efforts to prevent perinatal disease by the wider use of prophylactic intrapartum antibiotics.

Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid

OBJECTIVE

To determine if amnioinfusion with an antibiotic solution decreased the rate of clinical chorioamnionitis and puerperal endometritis in patients with meconium-stained amniotic fluid.

METHODS

Patients in labor at 36 weeks of gestation or greater with singleton pregnancies and meconium-stained amniotic fluid were randomized to receive either cefazolin, 1 g/1,000 mL, of normal saline (n = 90) or normal saline (n = 93) amnioinfusion. Rates of clinically diagnosed chorioamnionitis and endometritis and of suspected and culture-proven neonatal infection were determined.

RESULTS

Between the study and control groups, the incidences of clinical chorioamnionitis (7.8% vs. 8.6%), endometritis (2.4% vs. 3.5%), aggregate intrauterine infection (10.0% vs. 11.8%), suspected neonatal infection (17.8% vs. 21.5%), and proven neonatal infection (0.0% vs. 2.2%) were not significantly different.

CONCLUSIONS

Prophylactic use of cefazolin in amnioinfusions did not significantly reduce rates of maternal or neonatal infection in patients with meconium-stained amniotic fluid.