Multistate case-control study of maternal risk factors for neonatal group B streptococcal disease. The Active Surveillance Study Group

Neonatal Group B Streptococcus Disease

Group B Streptococcus (GBS) is an important cause of neonatal sepsis in term and preterm infants. Because GBS colonizes human genitourinary and gastrointestinal tracts, a significant focus of neonatal GBS disease prevention is to interrupt vertical transmission of GBS from mother to infant during parturition. Routine antepartum GBS screening in pregnant women, as well as widespread use of intrapartum antibiotic prophylaxis, have aided in overall reductions in neonatal GBS disease during the past 3 decades. However, neonatal GBS disease persists and may cause mortality and significant short- and long-term morbidity among survivors. Herein, we highlight contemporary epidemiology, microbial pathogenesis, and the clinical presentation spectrum associated with neonatal GBS disease. We summarize obstetric recommendations for antenatal GBS screening, indications for intrapartum antibiotic prophylaxis, and considerations for antibiotic selection. Finally, we review national guidelines for risk assessment and management of infants at risk for GBS disease.

Prevention of Early-Onset Neonatal Group B Streptococcal Disease: A Comprehensive Review of Major Guidelines

Importance

Group B Streptococcus (GBS) colonization during pregnancy is associated with significant neonatal morbidity and mortality and represents a major public health concern, often associated with poor screening and management.

Objective

The aim of this study was to review and compare the most recently published influential guidelines on the screening and management of this clinical entity during antenatal and intrapartum periods.

Evidence Acquisition

A descriptive review of guidelines from the American College of Obstetricians and Gynecologists, the Royal College of Obstetricians and Gynecologists, the Royal Australian and New Zealand College of Obstetricians and Gynecologists, and the Society of Obstetricians and Gynecologists of Canada on the prevention of early-onset neonatal group B streptococcal disease was carried out.

Results

There is a consensus among the reviewed guidelines regarding the optimal screening specimen type, indications for intrapartum antibiotic administration such as bacteriuria during pregnancy, clinical signs of chorioamnionitis or maternal pyrexia, and history of GBS-related neonatal disease. There is also agreement on several conditions where no intervention is recommended, that is, antepartum treatment of GBS and GBS-positive women with planned cesarean delivery and intact membranes. Controversy exists regarding the optimal screening time, with the Royal College of Obstetricians and Gynecologists stating against routine screening and on management strategies related to preterm labor and preterm prelabor rupture of membranes.

Conclusions

The development of consistent international practice protocols for the timely screening of GBS and effective management of this clinical entity both during pregnancy and the intrapartum period seems of paramount importance to safely guide clinical practice and subsequently improve neonatal outcomes.

Group B Streptococcus and the risk of perinatal morbidity and mortality following term labor

Streptococcus agalactiae (group B Streptococcus) colonizes the genital tract of approximately 20% of pregnant women. In the absence of intervention, approximately 1% of infants born to colonized mothers exhibit a clinical infection. This has led to implementation of screening and intervention in the form of intrapartum antibiotic prophylaxis in many countries, including the United States. However, screening has not been introduced in a substantial minority of other countries because of the absence of supportive level 1 evidence, the very large number needed to treat to prevent 1 case, and concerns about antimicrobial resistance. Optimal screening would involve rapid turnaround (to facilitate intrapartum testing) and report antibiotic sensitivity, but no such method exists. There is significant scope for a personalized medicine approach, targeting intrapartum antibiotic prophylaxis to cases at greatest risk, but the pathogen and host factors determining the risk of invasive disease are incompletely understood. Epidemiologic data have indicated the potential of prelabor invasion of the uterus by group B Streptococcus, and metagenomic analysis revealed the presence of group B Streptococcus in the placenta in approximately 5% of pregnant women at term before onset of labor and membrane rupture. However, the determinants and consequences of prelabor invasion of the uterus by group B Streptococcus remain to be established. The vast majority (98%) of invasive neonatal disease is caused by 6 serotypes, and hexavalent vaccines against these serotypes have completed phase 2 trials. However, an obstacle to phase 3 studies is conducting an adequately powered trial to demonstrate clinical effectiveness given that early-onset disease affects approximately 1 in 1000 births in the absence of vaccination.

Microbiologic Epidemiology of Early-onset Sepsis in Neonates Born at ≥35 0/7 Weeks' Gestation in Korea During 2009-2018

BACKGROUND

Sepsis within the first 3 days of life remains a leading cause of neonatal mortality and morbidity. However, few studies have addressed the epidemiology of sepsis in late preterm and term neonates, particularly in Asia. We aimed to estimate the epidemiology of early-onset sepsis (EOS) in neonates born at ≥35 0/7 weeks' gestation in Korea.

METHODS

A retrospective study was conducted in neonates with proven EOS born at ≥35 0/7 weeks' gestation from 2009 to 2018 at seven university hospitals. EOS was defined as identifying bacteria from a blood culture within 72 hours after birth.

RESULTS

A total of 51 neonates (0.36/1,000 live births) with EOS were identified. The median duration from birth to the first positive blood culture collection was 17 hours (range, 0.2-63.9). Among the 51 neonates, 32 (63%) patients were born by vaginal delivery. The median Apgar score was 8 (range, 2-9) at 1 minute and 9 (range, 4-10) at 5 minutes. The most common pathogen was group B Streptococcus (n = 21; 41.2%), followed by coagulase-negative staphylococci (n = 7; 13.7%) and Staphylococcus aureus (n = 5, 9.8%). Forty-six (90.2%) neonates were treated with antibiotics on the first day of symptom onset, and 34 (73.9%) neonates received susceptible antibiotics. The overall 14-day case-fatality rate was 11.8%.

CONCLUSION

This is the first multicenter study on the epidemiology of proven EOS in neonates born at ≥35 0/7 weeks' gestation and found that group B Streptococcus was the most common pathogen in Korea.

Group B Streptococcus in Pregnancy

To decrease risk of early-onset neonatal sepsis from group B streptococcus (GBS), pregnant patients should undergo screening between 36 0/7 and 37 6/7 weeks' gestation. Patients with a positive vaginal-rectal culture, GBS bacteriuria , or history of newborn with GBS disease should receive intrapartum antibiotic prophylaxis (IAP) with an agent targeting GBS. If GBS status is unknown at time of labor, IAP should be administered in cases of preterm birth, rupture of membranes for >18 hours, or intrapartum fever. The antibiotic of choice is intravenous penicillin; alternatives should be considered in cases of penicillin allergy depending on allergy severity.

Serotype distribution and incidence of invasive early onset and late onset group B streptococcal disease amongst infants in Singapore

Background

The current group B streptococcal (GBS) preventive measures had reduced invasive GBS early onset disease (EOD) incidences worldwide, but the late onset disease (LOD) incidences had remained unchanged. Administration of a safe and effective GBS vaccine in addition to the current strategies were thought to be the next steps in reducing the incidences of invasive GBS infection especially LOD. In this study, we aimed to examine the causative GBS serotypes in invasive GBS disease, determine the incidences of EOD and LOD, and compare the risk factors between EOD and LOD.

Methods

A retrospective study of infants ≤ 90-day-old over an 8-year period (2010–2017). The incidences of EOD and LOD were obtained by using patients with EOD and LOD who were born in our institution as the numerator and the live births in our institution per year of the study period as the denominator. Available GBS isolates were serotyped by the National Public Health Laboratory using capsular serotyping methods. The risk factors of EOD and LOD were compared.

Results

A total of 71 infants were identified; 16 (22.5%) and 55 (77.5%) of them had EOD and LOD, respectively. Serotype III (n = 42, 71.2%) was the most common serotype amongst the 59 isolates available for serotyping. Serotypes Ia, Ib, II, III, and V accounted for 98.3% (n = 58) of the invasive GBS diseases. The overall incidence was 0.42 per 1000 live births. The mean incidences of EOD and LOD were 0.13 per 1000 live births and 0.29 per 1000 live births, respectively. On multivariate analysis, risk factors for LOD as compared to EOD were: Chinese ethnicity (OR 27.1, 95% CI 3.0–243.1, p = 0.003) and negative/unknown maternal GBS status (OR 20.0, 95% CI 2.0–250.0, p = 0.012). Prematurity and intrapartum risk factors (peripartum maternal pyrexia, prolonged rupture of membrane) of EOD were not associated with LOD.

Conclusions

The LOD incidence had remained higher than EOD incidence in our cohort. A GBS vaccine that covers the major causative serotypes found in our cohort can potentially reduce the overall GBS disease burden in the country.

Group B streptococcal infections in infants in Iceland: clinical and microbiological factors

Introduction. Group B streptococcus (GBS) is a leading cause of invasive neonatal infections. These have been divided into early-onset disease (EOD; <7 days) and late-onset disease (LOD; 7-89 days), with different GBS clonal complexes (CCs) associated with different disease presentations.Hypothesis. Different GBS CCs are associated with timing of infection (EOD or LOD) and clinical presentation (sepsis, meningitis or pneumonia).Aim. To study infant GBS infections in Iceland from 1975 to 2019. Are specific GBS CCs related to disease presentation? Is CC17 overrepresented in infant GBS infections in Iceland?Methodology. All culture-confirmed invasive GBS infections in infants (<90 days) in Iceland from 1975 to 2019 were included. Clinical information was gathered from medical records.Results. A total of 127 invasive GBS infections in infants were diagnosed, but 105 infants were included in the study. Of these, 56 had EOD and 49 had LOD. The incidence of GBS infections declined from 2000 onwards but increased again at the end of the study period. Furthermore, there was a significant increase in LOD over the study period (P=0.0001). The most common presenting symptoms were respiratory difficulties and fever and the most common presentation was sepsis alone. Approximately one-third of the cases were caused by GBS CC17 of serotype III with surface protein RIB and pili PI-1+PI-2b or PI-2b. CC17 was significantly associated with LOD (P<0.001).Conclusion. CC17 is a major cause of GBS infection in infants in Iceland. This clone is associated with LOD, which has been increasing in incidence. Because intrapartum antibiotic prophylaxis only prevents EOD, it is important to continue the development of a GBS vaccine in order to prevent LOD infections.

Group B streptococcal colonization: Prevalence and impact of smoking in women delivering term or near term neonates in a large tertiary care hospital in the southern United States

Background and hypothesis

The role of smoking as a risk factor for group B streptococcal (GBS) colonization in women during pregnancy has not been previously adequately explored. We hypothesized that women of term or near term neonates who smoked during pregnancy were more likely to have GBS colonization than their non-smoking counterparts.

Methods

The electronic health records (EHRs) of a convenience sample of women delivering in an inner-city university tertiary care center were reviewed. The outcome variable of interest was maternal GBS colonization during pregnancy. The primary independent variable of interest was tobacco smoking during pregnancy, determined from the EHRs by the number of cigarettes smoked during gestation. Descriptive statistics were conducted and categorical data were compared by the Fischer’s exact test. Multiple logistic regression analysis was further conducted to determine the independent impact of tobacco smoke exposure on GBS colonization.

Results

The prevalence of maternal GBS colonization was 35% among the study population. In the univariate analyses, factors associated with maternal GBS colonization were tobacco smoking during pregnancy (P of trend <0.001), Race (P<0.001), maternal age <20 years (P = 0.006), low birthweight <2500 gm (P = 0.020), maternal drug use (P = 004), and gestational age <37 (P = 0.041). In a multiple logistic regression analysis, tobacco smoking during pregnancy remained the most significant predictor of GBS colonization. Women who smoked during pregnancy were more than twice more likely to be colonized than their non-smoking counterparts (OR = 2.6; 95% CI = 1.5–4.6; p<0.001). Maternal age was the only other significant predictor with younger mothers more than one and a half time more likely to be colonized than their older counterparts (OR = 1.65; 95% CI = 1.02–2.68; P = 0.04).

Conclusion

The prevalence of GBS colonization in this institution was consistent with recent national rates. Smoking and maternal age were identified as two independent risk factors for GBS colonization during pregnancy. Further studies are needed to confirm these findings.

Prevalence of rectovaginal colonization by group B Streptococcus in pregnant women seen at prenatal care program of a health organization

Objective

To evaluate the prevalence of group B Streptococci in pregnant women of a corporate health program, as well as the epidemiological correlations.

Methods

This retrospective study used medical records of patients who participated of the prenatal care program at a private hospital in the city of São Paulo (SP), Brazil, from 2015 to 2016. Those who abandoned the program or had incomplete data in their medical records were excluded. Quantitative variables were described by means, standard deviations, median, minimal and maximal values. Parity and socioeconomic status were described by absolute frequency and percentages. We used logistic regression models in the software (SPSS) to analyze correlations of variables according to vaginal-rectal culture, considering a 95%CI and p-values. Variables were age, number of pregnancies, weight gain in pregnancy and gestational age at delivery.

Results

A total of 347 medical records were included, and after applying the exclusion criteria, 287 medical records composed the final sample. Patients’ age ranged between 17 and 44 years. Mean age was 30.6 years, 67 patients had positive result for group B Streptococcus (prevalence of 23.3%; 95%CI: 18.7-28.5).

Conclusion

Considering the high prevalence of group B Streptococcus in our service, the antibiotic prophylaxis strategy based on rectovaginal culture screening approach seems to be cost-effective.

Nationwide epidemiology of early-onset sepsis in Israel 2010-2015, time to re-evaluate empiric treatment

AIM

Early-onset neonatal sepsis (EOS) may lead to significant morbidity and mortality, yet the recommended antimicrobials have not changed for many years. We aimed to optimise EOS treatment by examining EOS pathogens, resistance rates and resistance risk factors.

METHODS

A retrospective, nationwide cohort study analysing 2010-2015 EOS data in Israel.

RESULTS

The 21 participating centres constitute 92% of the total birth cohort (around 180 000 live births/year). Of 549 EOS neonates (0.57/1000 live births), 306 (56%) and 243 (44%) were full-term and preterm, respectively (0.35 vs. 2.94 per/1000 live births). Gram-negative pathogens predominated, especially in preterms. Escherichia coli and Streptococcus agalactiae were most common pathogens (0.2 and 0.19 per 1000 live births, respectively). In 277 Gram-negatives, 16%, 14%, 8% and 3% were gentamicin-resistant, extended-spectrum beta-lactamase (ESBL)-positive, gentamicin-resistant and ESBL-positive, and amikacin-resistant, respectively; preterms had higher resistance rates. No risk factors for antimicrobial resistance were identified. Mortality was reported in 21% of Gram-negative EOS versus 7% of Gram-positive EOS [OR 3.4 (95% CI 1.8-6.2), p < 0.01].

CONCLUSION

In this nationwide study, EOS was caused predominantly by Gram-negatives, with high gentamicin resistance and ESBL phenotype rates, without identifiable resistance risk factors. As EOS is life-threatening, modification of empiric therapy for amikacin-based regimens should be considered, mainly in preterms.

No. 298-The Prevention of Early-Onset Neonatal Group B Streptococcal Disease

OBJECTIVE

To review the evidence in the literature and to provide recommendations on the management of pregnant women in labour for the prevention of early-onset neonatal group B streptococcal disease. The key revisions in this updated guideline include changed recommendations for regimens for antibiotic prophylaxis, susceptibility testing, and management of women with pre-labour rupture of membranes.

OUTCOMES

Maternal outcomes evaluated included exposure to antibiotics in pregnancy and labour and complications related to antibiotic use. Neonatal outcomes of rates of early-onset group B streptococcal infections are evaluated.

EVIDENCE

Published literature was retrieved through searches of MEDLINE, CINAHL, and The Cochrane Library from January 1980 to July 2012 using appropriate controlled vocabulary and key words (group B streptococcus, antibiotic therapy, infection, prevention). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to May 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

The recommendations in this guideline are designed to help clinicians identify and manage pregnancies at risk for neonatal group B streptococcal disease to optimize maternal and perinatal outcomes. No cost-benefit analysis is provided.

SUMMARY STATEMENT

There is good evidence based on randomized control trial data that in women with pre-labour rupture of membranes at term who are colonized with group B streptococcus, rates of neonatal infection are reduced with induction of labour (I). There is no evidence to support safe neonatal outcomes with expectant management in this clinical situation.

RECOMMENDATIONS

Management of Infants at Risk for Group B Streptococcal Disease

Group B streptococcal (GBS) infection remains the most common cause of neonatal early-onset sepsis and a significant cause of late-onset sepsis among young infants. Administration of intrapartum antibiotic prophylaxis is the only currently available effective strategy for the prevention of perinatal GBS early-onset disease, and there is no effective approach for the prevention of late-onset disease. The American Academy of Pediatrics joins with the American College of Obstetricians and Gynecologists to reaffirm the use of universal antenatal microbiologic-based testing for the detection of maternal GBS colonization to facilitate appropriate administration of intrapartum antibiotic prophylaxis. The purpose of this clinical report is to provide neonatal clinicians with updated information regarding the epidemiology of GBS disease as well current recommendations for the evaluation of newborn infants at risk for GBS disease and for treatment of those with confirmed GBS infection. This clinical report is endorsed by the American College of Obstetricians and Gynecologists (ACOG), July 2019, and should be construed as ACOG clinical guidance.

Risk factors for group B streptococcus early-onset disease: an Italian, area-based, case-control study

Purpose: Intrapartum antibiotic prophylaxis (IAP) prevents group B streptococcus (GBS) early-onset disease (EOD). No European study evaluates the relative impact of risk factors (RFs) for EOD after a screening-based strategy and widespread IAP use We aimed to evaluate the risks of EOD in an Italian region where a screening-based strategy for preventing EOD was implemented.Materials and methods: Cases of EOD born at or above 35 weeks' gestation were reviewed and matched with controls.Results: There were 109 cases of EOD among 532,154 live births. Most cases had negative GBS prenatal screening (56/91, 61.5%) and were unexposed to IAP (86/109, 78.9%). At multivariate analysis, GBS bacteriuria (OR = 6.99), positive prenatal screening (OR = 13.7) and maternal intrapartum fever (OR = 188.3) were associated with an increased risk of EOD, whereas intrapartum beta-lactam antibiotics were associated with a decreased risk of EOD (≥4 h: OR = 0.008; <4 h: OR = 0.04). Neonates born to nonfebrile, GBS positive pregnant women, receiving beta-lactam antibiotics had very low probability of EOD, particularly if IAP was adequate.Conclusions: GBS positive prenatal screening, GBS bacteriuria and intrapartum fever are associated with EOD. Intrapartum beta-lactam antibiotics reduce the probability of EOD in neonates born to nonfebrile mothers.

Prevention of Group B Streptococcal Early-Onset Disease in Newborns: ACOG Committee Opinion, Number 782

Group B streptococcus (GBS) is the leading cause of newborn infection. The primary risk factor for neonatal GBS early-onset disease (EOD) is maternal colonization of the genitourinary and gastrointestinal tracts. Approximately 50% of women who are colonized with GBS will transmit the bacteria to their newborns. Vertical transmission usually occurs during labor or after rupture of membranes. In the absence of intrapartum antibiotic prophylaxis, 1-2% of those newborns will develop GBS EOD. Other risk factors include gestational age of less than 37 weeks, very low birth weight, prolonged rupture of membranes, intraamniotic infection, young maternal age, and maternal black race. The key obstetric measures necessary for effective prevention of GBS EOD continue to include universal prenatal screening by vaginal-rectal culture, correct specimen collection and processing, appropriate implementation of intrapartum antibiotic prophylaxis, and coordination with pediatric care providers. The American College of Obstetricians and Gynecologists now recommends performing universal GBS screening between 36 0/7 and 37 6/7 weeks of gestation. All women whose vaginal-rectal cultures at 36 0/7-37 6/7 weeks of gestation are positive for GBS should receive appropriate intrapartum antibiotic prophylaxis unless a prelabor cesarean birth is performed in the setting of intact membranes. Although a shorter duration of recommended intrapartum antibiotics is less effective than 4 or more hours of prophylaxis, 2 hours of antibiotic exposure has been shown to reduce GBS vaginal colony counts and decrease the frequency of a clinical neonatal sepsis diagnosis. Obstetric interventions, when necessary, should not be delayed solely to provide 4 hours of antibiotic administration before birth. This Committee Opinion, including , , and , updates and replaces the obstetric components of the CDC 2010 guidelines, "Prevention of Perinatal Group B Streptococcal Disease: Revised Guidelines From CDC, 2010."

Epidemiological characterization of serotype group B Streptococci neonatal infections associated with interleukin-6 level as a sensitive parameter for the early diagnosis

Group B streptococcal infection (Streptococcus agalactiae) is one of the leading causes of life-threatening disease in the early neonatal period, resulting in sepsis, pneumonia, and meningitis. During invasive infections, an excessive release of pro-inflammatory cytokine, such as interleukin-6 (IL-6), thus IL-6 gene is significant, as a diagnostic marker of systemic infection of the newborns. The present study aimed to describe the epidemiology diagnostic of GBS disease in neonatal by phenotypic and genotypic methods. Nine hundred and ninety-six samples were taken at Maternity and Children Hospital, Jeddah, Saudi Arabia for a period of one year (2011-2012). Results indicated that out of 217 infected samples, twenty (9.23.0%) were positive for group B Streptococci bacteria. This study also shows that female infants are more susceptible than males. The level of IL-6 was higher in mothers above 30 years. Twenty positive Streptococci group B isolates showed bands with the cylE gene primers in the border between 228 bp, 267 bp and 50 bp. Molecular detection by Real time polymerase chain reaction was also done to detect the target (Sip gene) encoding the Sip surface immunogenic protein. Specific primers and TaqMan probe were chosen for this purpose. A Real-time PCR method targeting the sip gene of GBS in neonates after delivery has been evaluated.

Late Onset Streptococcus agalactiae Meningitis following Early Onset Septicemia: A Preventable Disease?

We report a neonate who presented with early onset Streptococcus agalactiae or group B streptococcus (GBS) septicemia within 24 hours of birth. After discharge at day 14, she went on to develop late onset GBS meningitis at 36 days of age. The infant was treated with intravenous antibiotics on both occasions and eventually discharged home with no apparent sequelae. We address issues associated with GBS infection in infancy including the demographics, risk factors, and the risk of late onset GBS meningitis following an early onset GBS infection. The major source of GBS in early onset GBS disease is maternal birth canal GBS colonization. On the other hand, nosocomial cross-infection is an important source of GBS in late onset disease. Penicillin remains the current treatment of choice for GBS infection. Given the rapid onset and progression within hours of birth and lack of an effective solution for preventing late onset GBS, administration of an effective GBS vaccine in pregnancy could provide a sensible and cost-effective solution in all settings.

Group B Streptococcal infection in neonates and colonization in pregnant women: An epidemiological retrospective analysis

BACKGROUND

Group B Streptococcus (GBS) infection is one of the major causes of neonatal morbidity and mortality. Universal GBS screening with intrapartum antibiotic prophylaxis (IAP) in pregnant women were initiated in 2012 in Taiwan. This study aimed to analyze the most recent maternal GBS colonization rate and the changes in neonatal GBS infection rate from 2011 to 2016.

METHODS

All pregnant women and their live born neonates between January 2011 and June 2016 were retrospectively reviewed. Whether GBS screening was done, screening results, presence of risk factors, the use of antibiotics, and neonatal outcome were analyzed. In addition, hospitalized neonates diagnosed with GBS infections were retrieved for comparison of early onset disease (EOD) (<7 days) and late onset disease (LOD) (≥7 days).

RESULTS

A total of 9535 women delivered babies during the study period. The maternal GBS screening rate was 71.0% and the colonization rate was 22.6%. The overall neonatal invasive GBS infection rate was 0.81 per 1000 live births and the vertical transmission rate was 1.2%. After 2012, the invasive neonatal GBS infection rate declined from 1.1-1.6‰ to 0.6-0.7‰ in 2014 and thereafter, the GBS EOD incidence rate declined from 2.8‰ to 0.0-0.6‰, but the LOD incidence rate remained approximately 0.7‰. Infants with EOD had strong association with obstetric risk factors.

CONCLUSIONS

Taiwan's universal GBS screening with IAP program reduced the incidence rate of neonatal GBS EOD to be lower than 1‰ after 2012. Pediatricians still should pay attention to infants with GBS LOD since its incidence rate remained unchanged.

Neonatal Group B Streptococcal Disease in Otherwise Healthy Infants: Failure of Specific Neonatal Immune Responses

Only a small proportion of newborn infants exposed to a pathogenic microorganism develop overt infection. Susceptibility to infection in preterm infants and infants with known comorbidities has a likely multifactorial origin and can be often attributed to the concurrence of iatrogenic factors, environmental determinants, underlying pathogenic processes, and probably genetic predisposition. Conversely, infection occurring in otherwise healthy full-term newborn infants is unexplained in most cases. Microbial virulence factors and the unique characteristics of the neonatal immune system only partially account for the interindividual variability in the neonatal immune responses to pathogens. We here suggest that neonatal infection occurring in otherwise healthy infants is caused by a failure of the specific protective immunity to the microorganism. To explain infection in term and preterm infants, we propose an extension of the previously proposed model of the genetic architecture of infectious diseases in humans. We then focus on group B streptococcus (GBS) disease, the best characterized neonatal infection, and outline the potential molecular mechanisms underlying the selective failure of the immune responses against GBS. In light of the recent discoveries of pathogen-specific primary immunodeficiencies and of the role of anticytokine autoantibodies in increasing susceptibility to specific infections, we hypothesize that GBS disease occurring in otherwise healthy infants could reflect an immunodeficiency caused either by rare genetic defects in the infant or by transmitted maternal neutralizing antibodies. These hypotheses are consistent with available epidemiological data, with clinical and epidemiological observations, and with the state of the art of neonatal physiology and disease. Studies should now be designed to comprehensively search for genetic or immunological factors involved in susceptibility to severe neonatal infections.

Prévention de l'infection néonatale à streptocoques du groupe B d'apparition précoce

OBJECTIF

Analyser les données issues de la littérature et formuler des recommandations sur la prise en charge des parturientes en vue de prévenir l'infection néonatale à streptocoques du groupe B d'apparition précoce. Parmi les révisions clés que renferme la présente directive clinique mise à jour, on trouve des modifications quant aux recommandations en ce qui concerne les schémas posologiques d'antibioprophylaxie, les épreuves de sensibilité et la prise en charge des femmes présentant une rupture prématurée des membranes.

ISSUES

Parmi les issues maternelles évaluées, on trouvait l'exposition aux antibiotiques au cours de la grossesse et du travail, ainsi que les complications associées à l'administration d'antibiotiques. Les issues néonatales associées aux taux d'infection néonatale à streptocoques du groupe B d'apparition précoce ont été évaluées. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed, CINAHL et The Cochrane Library entre janvier 1980 et juillet 2012, au moyen d'un vocabulaire contrôlé et de mots clés appropriés (« group B streptococcus », « antibiotic therapy », « infection », « prevention »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles. Aucune restriction n'a été appliquée en matière de date ou de langue. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'en mai 2013. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). AVANTAGES, DéSAVANTAGES ET COûTS: Les recommandations que renferme la présente directive clinique sont conçues de façon à aider les cliniciens à identifier et à assurer la prise en charge des grossesses exposées à un risque d'infection néonatale à streptocoques du groupe B, en vue d'optimiser les issues maternelles et périnatales. Aucune analyse de rentabilité n'est fournie. DéCLARATION SOMMAIRE: Nous disposons de bonnes données (issues d'essais comparatifs randomisés) indiquant que, chez les femmes présentant une rupture prématurée des membranes à terme qui sont colonisées par des streptocoques du groupe B, le déclenchement du travail entraîne une baisse des taux d'infection néonatale. (I) Aucune donnée ne permet de soutenir que, dans une telle situation clinique, la prise en charge non interventionniste permet l'obtention de bonnes issues néonatales. RECOMMANDATIONS.

The Prevention of Early-Onset Neonatal Group B Streptococcal Disease

OBJECTIVE

To review the evidence in the literature and to provide recommendations on the management of pregnant women in labour for the prevention of early-onset neonatal group B streptococcal disease. The key revisions in this updated guideline include changed recommendations for regimens for antibiotic prophylaxis, susceptibility testing, and management of women with pre-labour rupture of membranes.

OUTCOMES

Maternal outcomes evaluated included exposure to antibiotics in pregnancy and labour and complications related to antibiotic use. Neonatal outcomes of rates of early-onset group B streptococcal infections are evaluated.

EVIDENCE

Published literature was retrieved through searches of MEDLINE, CINAHL, and The Cochrane Library from January 1980 to July 2012 using appropriate controlled vocabulary and key words (group B streptococcus, antibiotic therapy, infection, prevention). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to May 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

The recommendations in this guideline are designed to help clinicians identify and manage pregnancies at risk for neonatal group B streptococcal disease to optimize maternal and perinatal outcomes. No cost-benefit analysis is provided.

SUMMARY STATEMENT

There is good evidence based on randomized control trial data that in women with pre-labour rupture of membranes at term who are colonized with group B streptococcus, rates of neonatal infection are reduced with induction of labour (I). There is no evidence to support safe neonatal outcomes with expectant management in this clinical situation.

RECOMMENDATIONS

Group B streptococcal immunisation of pregnant women for the prevention of early and late onset Group B streptococcal infection of the neonate as well as adult disease

INTRODUCTION

Early onset neonatal Group B streptococcal disease is preventable. Intrapartum antibiotic prophylaxis has resulted in a significant reduction in neonatal mortality and morbidity. National guidelines for the selection of women eligible for intrapartum antibiotic prophylaxis, whether screening-based or risk-based, differ according to the local burden of disease. Despite the introduction of intrapartum antibiotic prophylaxis, there remains a significant burden of disease, which can be resolved by better adherence to guidelines, rapid identification of maternal colonization or in the future, vaccination. Areas covered: The introduction of a vaccine to women in the third trimester is likely to further reduce the burden of disease and provide benefits beyond the prevention of early neonatal disease, including meningitis and disability following late onset disease. Development of specific polyvalent vaccines continues, but testing has challenges and may require surrogate markers or molecular-based techniques to manipulate antigenicity and immunogenicity. Expert commentary: Group B streptococcal vaccination using conjugated polyvalent vaccines against the major disease causing serotypes of Group B streptococcus, either alone, or in combination with a policy of intrapartum antibiotic prophylaxis, may decrease the burden of Group B streptococcus beyond that achieved by current use of intrapartum antibiotic prophylaxis alone.

Prevalence and antimicrobial susceptibility pattern of anorectal and vaginal group B Streptococci isolates among pregnant women in Jimma, Ethiopia

Background

Streptococcus agalactiae (group B Streptococcus, GBS) is the most frequent pathogen isolated from neonates with invasive bacterial disease and responsible for serious infections in newborns such as pneumonia, septicemia and meningitis. Infection is primarily acquired vertically from mothers colonized with GBS. However, the prevalence and antimicrobial susceptibility pattern of GBS among pregnant women in Ethiopia are less studied.

Methods

This cross-sectional study involved 126 pregnant women at 35–37 weeks of gestation attending the antenatal clinic at Jimma University Hospital. Anorectal and vaginal swabs were cultured on to Todd-Hewitt broth medium supplemented with Gentamicin and Nalidixic acid and subsequently sub-cultured on 5 % sheep blood agar followed by identification of isolates based on colonial morphology, Gram stain, catalase reaction, hippurate hydrolysis and Christie, Atkins, Munch-Petersen (CAMP) test, and testing for their susceptibility to antimicrobial agents using the Kirby–Bauer method.

Results

The overall carriage rate of GBS was 19.0 % (24/126), and the rectal and vaginal carrier rates were 14.3 % (18/126) and 10.4 % (13/126), respectively. Concomitant vaginal and anorectal colonization was recorded in 29.2 % (7/24) of the women who were culture positive. All GBS isolates were susceptible to penicillin G, ampicillin, and vancomycin, but a considerable proportion was resistant to clindamycin (3.2 %), erythromycin (6.5 %), ciprofloxacin (9.7 %), ceftriaxone (9.7 %), norfloxacin (12.9 %), cotrimoxazole (29 %), and tetracycline (45.2 %).

Conclusion

This study reveals high carriage rate of GBS among pregnant women compared to some previous studies in Ethiopia. However, further epidemiological investigations should be done in different parts of the country in order to know the actual GBS colonization rate of pregnant women and to consider the possibility of implementing prophylactic treatment to prevent potential adverse maternal and neonatal outcomes. Future studies should be conducted to reveal serotype distributions of GBS in this community.

Chorioamnionitis and Culture-Confirmed, Early-Onset Neonatal Infections

BACKGROUND

Current guidelines for prevention of neonatal group B streptococcal disease recommend diagnostic evaluations and empirical antibiotic therapy for well-appearing, chorioamnionitis-exposed newborns. Some clinicians question these recommendations, citing the decline in early-onset group B streptococcal disease rates since widespread intrapartum antibiotic prophylaxis implementation and potential antibiotic risks. We aimed to determine whether chorioamnionitis-exposed newborns with culture-confirmed, early-onset infections can be asymptomatic at birth.

METHODS

Multicenter, prospective surveillance for early-onset neonatal infections was conducted during 2006-2009. Early-onset infection was defined as isolation of a pathogen from blood or cerebrospinal fluid collected ≤ 72 hours after birth. Maternal chorioamnionitis was defined by clinical diagnosis in the medical record or by histologic diagnosis by placental pathology. Hospital records of newborns with early-onset infections born to mothers with chorioamnionitis were reviewed retrospectively to determine symptom onset.

RESULTS

Early-onset infections were diagnosed in 389 of 396,586 live births, including 232 (60%) chorioamnionitis-exposed newborns. Records for 229 were reviewed; 29 (13%) had no documented symptoms within 6 hours of birth, including 21 (9%) who remained asymptomatic at 72 hours. Intrapartum antibiotic prophylaxis exposure did not differ significantly between asymptomatic and symptomatic infants (76% vs 69%; P = .52). Assuming complete guideline implementation, we estimated that 60 to 1400 newborns would receive diagnostic evaluations and antibiotics for each infected asymptomatic newborn, depending on chorioamnionitis prevalence.

CONCLUSIONS

Some infants born to mothers with chorioamnionitis may have no signs of sepsis at birth despite having culture-confirmed infections. Implementation of current clinical guidelines may result in early diagnosis, but large numbers of uninfected asymptomatic infants would be treated.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

The prevention of early-onset neonatal group B streptococcal disease

OBJECTIVE

To review the evidence in the literature and to provide recommendations on the management of pregnant women in labour for the prevention of early-onset neonatal group B streptococcal disease. The key revisions in this updated guideline include changed recommendations for regimens for antibiotic prophylaxis, susceptibility testing, and management of women with pre-labour rupture of membranes.

OUTCOMES

Maternal outcomes evaluated included exposure to antibiotics in pregnancy and labour and complications related to antibiotic use. Neonatal outcomes of rates of early-onset group B streptococcal infections are evaluated.

EVIDENCE

Published literature was retrieved through searches of MEDLINE, CINAHL, and The Cochrane Library from January 1980 to July 2012 using appropriate controlled vocabulary and key words (group B streptococcus, antibiotic therapy, infection, prevention). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to May 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

The recommendations in this guideline are designed to help clinicians identify and manage pregnancies at risk for neonatal group B streptococcal disease to optimize maternal and perinatal outcomes. No cost-benefit analysis is provided.

SUMMARY STATEMENT

There is good evidence based on randomized control trial data that in women with pre-labour rupture of membranes at term who are colonized with group B streptococcus, rates of neonatal infection are reduced with induction of labour. (I) There is no evidence to support safe neonatal outcomes with expectant management in this clinical situation.

RECOMMENDATIONS

1. Offer all women screening for colonization with group B streptococcus at 35 to 37 weeks' gestation with culture taken from one swab first to the vagina and then to the rectum (through the anal sphincter). (II-1A) This includes women with planned Caesarean delivery because of their risk of labour or ruptured membranes earlier than the scheduled Caesarean delivery. (II-2B) 2. Because of the association of heavy colonization with early onset neonatal disease, provide intravenous antibiotic prophylaxis for group B streptococcus at the onset of labour or rupture of the membranes to: • any woman positive for group B streptococcus by vaginal/rectal swab culture screening done at 35 to 37 weeks' gestation (II-2B); • any woman with an infant previously infected with group B streptococcus (II-3B); • any woman with documented group B streptococcus bacteriuria (regardless of level of colony-forming units) in the current pregnancy. (II-2A) 3. Manage all women who are < 37 weeks' gestation and in labour or with rupture of membranes with intravenous group B streptococcus antibiotic prophylaxis for a minimum of 48 hours, unless there has been a negative vaginal/rectal swab culture or rapid nucleic acid-based test within the previous 5 weeks. (II-3A) 4. Treat all women with intrapartum fever and signs of chorioamnionitis with broad spectrum intravenous antibiotics targeting chorioamnionitis and including coverage for group B streptococcus, regardless of group B streptococcus status and gestational age. (II-2A) 5. Request antibiotic susceptibility testing on group B streptococcus-positive urine and vaginal/rectal swab cultures in women who are thought to have a significant risk of anaphylaxis from penicillin. (II-1A) 6. If a woman with pre-labour rupture of membranes at ≥ 37 weeks' gestation is positive for group B streptococcus by vaginal/rectal swab culture screening, has had group B streptococcus bacteriuria in the current pregnancy, or has had an infant previously affected by group B streptococcus disease, administer intravenous group B streptococcus antibiotic prophylaxis. Immediate obstetrical delivery (such as induction of labour) is indicated, as described in the Induction of Labour guideline published by the Society of Obstetricians and Gynaecologist in September 2013. (II-2B) 7. At ≥ 37 weeks' gestation, if group B streptococcus colonization status is unknown and the 35- to 37-week culture was not performed or the result is unavailable and the membranes have been ruptured for greater than 18 hours, administer intravenous group B streptococcus antibiotic prophylaxis. (II-2B) 8. If a woman with pre-labour rupture of membranes at < 37 weeks' gestation has an unknown or positive group B streptococcus culture status, administer intravenous group B streptococcus prophylaxis for 48 hours, as well as other antibiotics if indicated, while awaiting spontaneous or obstetrically indicated labour. (II-3B).

Maternal and neonatal risk factors for early-onset group B streptococcal disease: a case control study

Objectives

To identify the prominent maternal and neonatal risk factors associated with early-onset group B streptococcus (EOGBS) disease in neonates and to determine their importance by comparing them with a control group.

Setting

Neonatal unit at King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia.

Patients

Cases were infants <7 days of age with invasive group B streptococcus (GBS) disease diagnosed between January 1, 2000 and December 31, 2009. Controls were healthy infants born in the same hospital during the same period having the same birth weight and gestational age category.

Main outcome measures

Maternal risk factors for developing EOGBS disease, feto–maternal and neonatal clinical data, their morbidities, mortalities, and length of hospital stay.

Results

A total of 99 cases and 200 controls were included. The majority of cases presented in the first 72 hours of life (62/99 [63.9%]), of which 87/99 (89.7%) had at least one clinical risk factor for the development of EOGBS disease. Mothers of neonates with EOGBS disease were more likely to have GBS bacteriuria (odds ratio [OR] 10.76, 95% confidence interval [CI] 1.24–93.42), infection in the peripartum period (OR 8.92, CI 2.87–27.68), and temperature ≥38°C (OR 7.10, CI 2.50–20.17). GBS disease was associated with premature rupture of membranes and fetal tachycardia (P<0.01 for both). Neonates with EOGBS disease were more likely to have respiratory distress disease and convulsions, require tube feeding, and have longer hospital stays compared with the controls (P<0.01 for all). Stepwise multiple logistic regression has identified three risk factors that were associated with the highest tendency for the development of EOGBS disease. These were lack of antenatal attendance (OR =0.30 and CI 0.98–0.88), rupture of membranes (OR =9.62 and CI 3.1–29.4), and antibiotic use in labor (OR =0.16 and CI 0.38–0.67).

Conclusion

A number of maternal risk factors were significantly associated with EOGBS disease. Taking these factors into consideration may result in preventing the occurrence of EOGBS disease, improve maternal and neonatal medical care, decrease their hospital stay, and reduce unnecessary hospital resource utilization.

Comparison of various culture methods for isolation of group B streptococcus from intrapartum vaginal colonization

AIMS

Group B Streptococcus (GBS) is one of the most common causes of neonatal sepsis throughout the world. Reports of vaginal colonization of GBS in India are few and variable. A study was conducted on pregnant women in a tertiary care hospital to compare various methods for isolation of GBS, to study the prevalence of GBS in pregnant women in third trimester, and to determine risk factors for GBS colonization.

SETTINGS AND DESIGN

Observational descriptive study.

MATERIALS AND METHODS

High vaginal swabs from 150 pregnant women in their third trimester were used to compare three methods for isolation of GBS viz. direct culture on 5% Sheep Blood agar, direct culture on selective Columbia Blood Agar and culture in LIM enrichment broth with subsequent culture on 5% Sheep Blood agar. A history of associated risk factors was also taken.

STATISTICAL ANALYSIS USED

Statistical analysis was performed by Chi-square test.

RESULTS

Isolation was best from LIM enrichment broth with subsequent culture on 5% Sheep Blood Agar. Prevalence of GBS colonization by using culture method was 12.67%. Most frequently associated risk factor was intrapartum fever (42.11%).

CONCLUSIONS

Standard Culture Method using LIM enrichment should be adopted as standard practice for isolation of GBS from vaginal swabs.

Risk factors for group B streptococcus colonization among pregnant women in Korea

OBJECTIVES

To identify obstetric and maternal factors related to Group B Streptococcus (GBS) colonization in pregnant women in Korea.

METHODS

The study was conducted between the years 2006-2008 in four hospitals, Cheil and Eulji hospital in Seoul, and Motae and Eulji hospital in Daejeon. We recruited 2,644 pregnant women between 35 to 37 weeks of gestation who had visited for antenatal care. Participants completed a questionnaire, and urine, vaginal and rectal specimens were obtained and cultured using selective broth media. After delivery, medical records were reviewed.

RESULTS

GBS colonization was significantly associated with hospital, age group, education, frequency of pregnancy, and premature rupture of membranes (PROM, more than 18 hours). After adjustment for other variables, Cheil hospital (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.20-3.52), and the first pregnancy (OR, 2.32; 95% CI, 1.12-4.81) remained significant. History of vaginitis showed marginal significance (OR, 1.50; 95% CI, 0.98-2.29).

CONCLUSION

To prevent GBS infection of neonates, clinicians should be alert to the potentially higher risk of GBS colonization in pregnant women in their first pregnancy, and women with premature rupture of membranes (PROM) (18 hours+) or who have a history of vaginitis.

Estimating the probability of neonatal early-onset infection on the basis of maternal risk factors

OBJECTIVE

To develop a quantitative model to estimate the probability of neonatal early-onset bacterial infection on the basis of maternal intrapartum risk factors.

METHODS

This was a nested case-control study of infants born at ≥34 weeks' gestation at 14 California and Massachusetts hospitals from 1993 to 2007. Case-subjects had culture-confirmed bacterial infection at <72 hours; controls were randomly selected, frequency-matched 3:1 according to year and birth hospital. We performed multivariate analyses and split validation to define a predictive model based only on information available in the immediate perinatal period.

RESULTS

We identified 350 case-subjects from a cohort of 608,014 live births. Highest intrapartum maternal temperature revealed a linear relationship with risk of infection below 100.5°F, above which the risk rose rapidly. Duration of rupture of membranes revealed a steadily increasing relationship with infection risk. Increased risk was associated with both late-preterm and postterm delivery. Risk associated with maternal group B Streptococcus colonization is diminished in the era of group B Streptococcus prophylaxis. Any form of intrapartum antibiotic given >4 hours before delivery was associated with decreased risk. Our model showed good discrimination and calibration (c statistic = 0.800 and Hosmer-Lemeshow P = .142 in the entire data set).

CONCLUSIONS

A predictive model based on information available in the immediate perinatal period performs better than algorithms based on risk-factor threshold values. This model establishes a prior probability for newborn sepsis, which could be combined with neonatal physical examination and laboratory values to establish a posterior probability to guide treatment decisions.

Serine-rich repeat proteins and pili promote Streptococcus agalactiae colonization of the vaginal tract

Streptococcus agalactiae (group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal vaginal colonization poses a significant risk to the newborn; however, little is known about the specific bacterial factors that promote GBS colonization and persistence in the female reproductive tract. We have developed in vitro models of GBS interaction with the human female cervicovaginal tract using human vaginal and cervical epithelial cell lines. Analysis of isogenic mutant GBS strains deficient in cell surface organelles such as pili and serine-rich repeat (Srr) proteins shows that these factors contribute to host cell attachment. As Srr proteins are heavily glycosylated, we confirmed that carbohydrate moieties contribute to the effective interaction of Srr-1 with vaginal epithelial cells. Antibody inhibition assays identified keratin 4 as a possible host receptor for Srr-1. Our findings were further substantiated in an in vivo mouse model of GBS vaginal colonization, where mice inoculated with an Srr-1-deficient mutant exhibited decreased GBS vaginal persistence compared to those inoculated with the wild-type (WT) parental strain. Furthermore, competition experiments in mice showed that WT GBS exhibited a significant survival advantage over the ΔpilA or Δsrr-1 mutant in the vaginal tract. Our results suggest that these GBS surface proteins contribute to vaginal colonization and may offer new insights into the mechanisms of vaginal niche establishment.

Increasing incidence of late-onset neonatal invasive group B streptococcal infections in Iceland

BACKGROUND

Group B streptococci (GBS) may cause life-threatening invasive infections in infants. The incidence of these infections has been increasing during the last decades. The aim of the study was to determine the epidemiology of neonatal GBS infections to be able to implement therapeutic and preventive measures more effectively.

METHODS

A retrospective case study was conducted in Iceland that included all neonates with positive GBS cultures from blood or cerebrospinal fluid during the period 1975 to 2006. Serotyping of all available GBS isolates was performed.

RESULTS

A total of 87 children with 89 infections were included in the study. In all, 53 infants had early-onset (EO) GBS infections (occurring <7 days after birth) and 34 had late-onset (LO) infections (occurring on days 7-90). EO infections increased during the first 3 quartiles of the study period but decreased during the last quartile. LO infections increased throughout the entire study period. GBS was cultured from cerebrospinal fluid in 21 patients; 9 with EO and 12 with LO infections. Premature infants comprised 15 with EO and 14 with LO infections. Eight children died of GBS infection, 7 with EO and 1 with LO infections; no correlation with serotypes was found. Serotype III was most common for both EO (34%) and LO infections (62%).

CONCLUSION

The number of GBS infections increased during the study period. The decrease in EO infections in recent years could be attributed to intrapartum antibiotic treatment. The increasing number of LO infections is a concern.

Group B streptococcal disease in infants: progress in prevention and continued challenges

The burden of early-onset disease caused by group B Streptococcus (GBS) has decreased dramatically in the United States over the past 20 years. Universal culture-based screening at 35 to 37 weeks gestational age and use of intrapartum antibiotic prophylaxis are the cornerstones of prevention measures that have led to this decline. GBS, however, remains the leading cause of early-onset neonatal sepsis in the United States. Revised guidelines for prevention of perinatal GBS are planned for issuance in 2010. This article discusses implementation challenges for clinicians caring for pregnant women and newborns and presents an updated algorithm for neonatal management.

Epidemiology of neonatal group B streptococcal disease in the Netherlands before and after introduction of guidelines for prevention

OBJECTIVES

(1) To describe the epidemiology of neonatal group B streptococcal (GBS) disease over five years (1997-2001) in the Netherlands, stratified for proven and probable sepsis and for very early (<12 h), late early (12 h - <7 days) and late (7-90 days) onset sepsis. (2) To evaluate the effect of the introduction in January 1999 of guidelines for prevention of early onset GBS disease based on risk factors.

METHODS

Data on cases were collected in collaboration with the Dutch Paediatric Surveillance Unit and corrected for under-reporting by the capture-recapture technique.

RESULTS

Total incidence of proven very early onset, late early onset and late onset GBS sepsis was 0.32, 0.11 and 0.14 per 1000 live births, respectively, and of probable very early onset, late early onset and late onset GBS sepsis was 1.10, 0.18 and 0.02 per 1000 live births, respectively. Maternal risk factors were absent in 46% of the proven early onset cases. Considerably more infants with proven GBS sepsis were boys. 64% of the infants with proven very early onset GBS sepsis were first born compared with 47% in the general population. After the introduction of guidelines the incidence of proven early onset sepsis decreased considerably from 0.54 per 1000 live births in 1997-8 to 0.36 per 1000 live births in 1999-2001. However, there was no decrease in the incidence of meningitis and the case fatality rate in the first week of life. The incidence of late onset sepsis also remained unchanged.

CONCLUSION

After the introduction prevention guidelines based on risk factors there has been a limited decrease in the incidence of proven early onset GBS sepsis in the Netherlands. This study therefore recommends changing the Dutch GBS prevention guidelines.

Perinatal infection with Group B streptococci

Group B streptococcus (GBS) is a major cause of severe bacterial infection in newborns. Early neonatal GBS infection can be prevented by identifying high-risk pregnancies and administering intrapartum antibiotics. In the USA, a screening strategy has been introduced resulting in a reduction in early-onset GBS infection, but no decrease in late-onset neonatal GBS disease has been noted. In many European countries, a risk-based strategy is recommended. Vaccination may, in the future, be an alternative in preventing GBS infection in newborns.

Duration of Intrapartum Prophylaxis for Neonatal Group B Streptococcal Disease

OBJECTIVE

To examine published evidence regarding duration of intrapartum antibiotic prophylaxis administered to pregnant women colonized with group B Streptococcus (GBS) to reduce infant colonization with GBS and to prevent early-onset GBS sepsis.

DATA SOURCES

A search was conducted in The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2006), MEDLINE (1966 to January 2006), EMBASE (1980 to January 2006), CINAHL (1982 to January 2006), and in protocols and guidelines of the Centers for Disease Control and Prevention, American Academy of Pediatrics, and American College of Obstetrics and Gynecology.

METHODS OF STUDY SELECTION

All randomized controlled trials and observational studies in which duration of intrapartum antibiotic prophylaxis is reported relative to subsequent neonatal GBS colonization or sepsis were considered. Case series and study designs using historical cohorts or controls for comparison were excluded.

TABULATION, INTEGRATION, AND RESULTS

Three prospective cohort studies and one case-control study met inclusion criteria. Heterogeneity of study design and assembly of cohorts precluded meta-analysis. A systematic review of the individual studies was performed. All studies were rated as fair or poor validity with regard to their ability to evaluate duration of intrapartum prophylaxis and transmission of GBS to the newborn. All 4 studies were largely composed of women with existing risk factors for GBS disease of the newborn. One study supported more than 1 hour of prophylaxis, two studies supported more than 2 hours of prophylaxis, and one was inconclusive.

CONCLUSION

Despite unequivocal clinical guidelines recommending at least 4 hours of intrapartum antibiotic prophylaxis, there are no well-designed studies examining duration of intrapartum antibiotic prophylaxis for prevention of early-onset GBS disease of the newborn. We recommend continuing to initiate intrapartum prophylaxis according to the American College of Obstetricians and Gynecologists guidelines; however, the transmission of GBS to neonates exposed to less than 4 hours of intrapartum prophylaxis and their subsequent management require further study.

Impact and risk factors for early-onset group B streptococcal morbidity: analysis of a national, population-based cohort in Sweden 1997-2001

OBJECTIVES

To study early-onset group B streptococcal (EOGBS) morbidity, mortality, and maternal risk factors.

DESIGN

Observational, population-based, retrospective. Data from national registers and medical records.

SETTING

Sweden, 1997-2001.

POPULATION

Cohort of 640 infants with a diagnosis of GBS infection out of 435 070 live births.

METHOD

Infants with diagnoses GBS sepsis (P36.0) and/or pneumonia (P23.3) were analysed. In cases with P36.0, register data were validated against infant and maternal medical records. Odds ratios (OR) were estimated by multiple logistic regression.

MAIN OUTCOME MEASURES

Incidence of EOGBS morbidity, mortality, frequency of maternal risk factors and administration of intrapartum antibiotics.

RESULTS

There were 319 cases with EOGBS sepsis. Blood culture verified 174 cases. There were 145 with clinical sepsis and 180 with pneumonia only. The incidences were 0.40, 0.33, and 0.41 per 1000 live births, respectively. The mortality was 7.5, 0.7, and 2.2% in respective groups. The frequencies of established maternal risk factors were: membrane rupture > or =18 hours, 44%; prematurity, 26%; temperature during labour > or =38 degrees C, 22%. Novel maternal risk factors identified in verified cases were gestational age (GA) of 37 completed weeks (OR 3.5, 1.8-6.5) and gestational diabetes (OR 3.7, 1.8-8.5). When including clinical sepsis, also epidural anaesthesia, infant large for GA, postmaturity, and high maternal age were significant risk factors.

CONCLUSION

The incidence of verified EOGBS disease was 0.4 per 1000 live births with a total burden of EOGBS morbidity approximately three times higher. GA of 37 completed weeks and gestational diabetes were identified as additional significant risk factors.

Prevention of neonatal sepsis

Neonatal sepsis is a leading infectious cause of infant mortality. While use of intrapartum antibiotic prophylaxis in the United States has led to dramatic declines in perinatal sepsis caused by the bacteria group B streptococcus, interventions to prevent perinatal sepsis due to other causes have not yet been clearly defined. This article synthesizes information on neonatal sepsis disease burden, trends, and risk factors and reviews current and potential approaches to neonatal sepsis prevention.

Cost-effectiveness of different treatment strategies with intrapartum antibiotic prophylaxis to prevent early-onset group B streptococcal disease

OBJECTIVE

To estimate the costs and effects of different treatment strategies with intrapartum antibiotic prophylaxis to prevent early-onset group B streptococcal (GBS) disease in the Netherlands. The treatment strategies include a risk-based strategy, a screening-based strategy, a combined screening/risk-based strategy and the current Dutch guideline.

DESIGN

Cost-effectiveness analysis based on decision model.

SETTING

Obstetric care system in the Netherlands.

POPULATION/SAMPLE

Hypothetical cohort of 200,000 neonates.

METHODS

A decision analysis model was used to compare the costs and effects of different treatment strategies with no treatment. Baseline estimates were derived from literature and a survey among parents of children affected by GBS disease. The analysis was performed from a societal perspective, and costs and effects were discounted at a percentage of 3%. Main outcome measures Cost per quality adjusted of life-year (QALY).

RESULT

The risk-based strategy will prevent 352 cases of early-onset GBS for 5.0 million Euros, indicating a cost-effectiveness ratio of 7600 Euros per QALY gained. The combined screening risk-based strategy has comparable results. The current Dutch guideline resulted in lower effects for higher costs. The screening-based strategy shows the highest reduction in cases of early-onset GBS, however, at a cost-effectiveness ratio of 59,300 Euros per QALY gained. Introducing the polymerase chain reaction (PCR) test may lead to a more favourable cost-effectiveness ratio.

CONCLUSION

In the Dutch system, the combined screening/risk-based strategy and the risk-based strategy have reasonable cost-effectiveness ratios. If it becomes feasible to add the PCR test, the cost-effectiveness of the combined screening/risk-based strategy may even be more favourable.

Phosphoglycerate kinase inhibits epithelial cell invasion by group B streptococci

Group B streptococci (GBS) are opportunistic human pathogens that cause infection and invasive disease in newborns, pregnant women and non-pregnant adults. The internalization of GBS into eukaryotic cells occurs in an actin-microfilament dependent process. The objective of our study was to understand what host cell and/or bacterial factors may be involved in this process. We focused on alpha-actinin, an actin binding protein closely associated with cytoplasmic F-actin in the eukaryotic cell, to determine if it is involved in actin recruitment upon GBS internalization. Initial work revealed that GBS does not recruit alpha-actinin. However, it was found that alpha-actinin antibodies bound to the surface of the GBS, suggesting GBS possess surface-exposed actin binding protein(s). Slide agglutination experiments revealed that when the bacteria were emulsified with F-actin, visible agglutination occurred, further suggesting the presence of an actin binding protein on the GBS cell. Western blot analysis found that anti-alpha-actinin antibodies bound to a 42 kDa protein; mass spectra analysis identified this protein as GBS phosphoglycerate kinase (PGK). Competitive binding assays suggest that the PGK-actin interaction is not a factor in the initial binding of GBS to epithelial cells, however, treating epithelial cells with PGK prior to performing an invasion assay inhibited GBS internalization. This occurred in a dose dependent manner with 10 microg/mL of PGK inhibiting invasion by over 70%, and 50 microg/mL PGK inhibits GBS invasion completely.

Le streptocoque du groupe B en clinique anténatale et en salle de travail : un problème d’attitude systématique

OBJECTIVES

We wanted to evaluate the compliance to the local recommendations, similar to the CDC (Centers for Disease Control and prevention) recommendations launched in 1996, for the prevention of perinatal group B streptococcal (GBS) disease in the clinical practice of a academic maternity and to identify the causes of missed screening and antibiotic prophylaxis.

MATERIALS AND METHODS

Retrospective study of 1249 consecutive pregnancies between 1st January and 31th August 2002. The screening methods for GBS colonisation were the culture of rectovaginal swabs collected between 35 and 37 weeks and/or a rapid antigenic screening performed on a vaginal swab collected at the patient's admission for labor.

RESULTS

Rate of global screening was very high (97.8%): 28.8% of antenatal screening versus 90.3% during labor. An appropriate antibiotic prophylaxis was administered to only one-third of positive women when the screening was performed at admission to the labor room, whereas two-thirds of GBS-positive women screened between 35 and 37 weeks received their antibiotic prophylaxis. 2.4%o of the newborns were infected and 2.9% were colonized. Among the different risk factors, intrapartum fever was more often associated with maternal GBS colonisation. The observed sensitivity of the rapide antigenic test was 20.4%.

CONCLUSION

Compliance to guidelines is sometimes difficult in the clinical practice of an academic maternity. In our hands the rapid test for GBS screening had low sensitivity. The analysis of these data led to introducing a computerized algorithm in our maternity to improve the prevention of perinatal group B streptococcal disease.

Group B Streptococcal Colonization and Serotype-Specific Immunity in Healthy Elderly Persons

BACKGROUND

The burden from group B streptococcal (GBS) disease in elderly persons (age, >or=65 years) has increased. Rates of colonization and prevalence of antibodies against capsular polysaccharides (CPS) that might confer protection against invasive GBS disease in such persons are not defined.

METHODS

A cross-sectional survey was conducted in an outpatient setting in Houston. GBS colonization rates in this convenience sample were assessed by self-obtained vaginal and rectal specimens (for women) and rectal and urine specimens (for men). The CPS type distribution among GBS isolates was determined, and CPS-specific antibodies against GBS types Ia, Ib, II, III, and V were quantified by enzyme-linked immunosorbent assays.

RESULTS

The GBS colonization rate among 254 healthy elderly participants (mean age, 73 years) was 21.7%. CPS types Ia (22.8%), III (12.3%), and V (47.3%) predominated, and 12.3% of colonizing isolates were nontypeable. Random selection of 1 member of 33 participating married couples did not alter the overall colonization rate (21.7%) or GBS serotype distribution. The geometric mean concentrations of CPS-specific IgG in serum specimens were low and were significantly lower for GBS type V, compared with other serotypes (P<.001).

CONCLUSIONS

Adults >or=65 years of age are colonized with GBS at a rate similar to that of younger persons, but older adults are significantly more likely to carry type V, the leading cause of invasive disease in elderly persons, and to lack type V CPS-specific serum IgG. The CPS of type V GBS should be included in candidate GBS vaccines so that adults >or=65 years of age theoretically could be protected against invasive disease.