Factors associated with intrapartum transmission of group B Streptococcus

Enrichment culture evaluation and characterization of Streptococcus agalactiae among pregnant women in Japan

Introduction. Maternal screening tests and prophylactic antibiotics are important to prevent neonatal and infant group B streptococcal (GBS) infections.Hypothesis/Gap Statement. The performance of enrichment broth media for GBS screening that are available in Japan is unclear. Whole-genome data of GBS isolates from pregnant women in Japan is lacking.Aim. The aim of this study was to compare the protocol performance of six enrichment broths and two subculture agar plates, which were all available in Japan, for GBS detection. In addition, we showed whole-genome data of GBS isolates from pregnant women in Japan.Methodology. We collected 133 vaginal-rectal swabs from pregnant women visiting clinics and hospitals in Nagasaki Prefecture, Japan, and compared the protocol performance of 6 enrichment broths and 2 subculture agar plates. All GBS isolates collected in this study were subjected to whole-genome sequencing analysis.Results. We obtained 133 vaginal-rectal swabs from pregnant women at 35-37 weeks of gestation from 8 private clinics and 2 local municipal hospitals within Nagasaki Prefecture, Japan. The detection rate of the protocol involving the six enrichment broths and subsequent subcultures varied between 95.5 and 100 %, depending on the specific choice of enrichment broth. The GBS carriage rate among pregnant women in this region was 18.8 %. All 25 isolates derived from the swabs were susceptible to penicillin, whereas 48 and 36 % of the isolates demonstrated resistance to erythromycin and clindamycin, respectively. The distribution of serotypes was highly diverse, encompassing seven distinct serotypes among the isolates, with the predominant serotype being serotype V (n = 8). Serotype V isolates displayed a tendency towards increased resistance to erythromycin and clindamycin, with all resistant isolates containing the ermB gene.Conclusion. There was no difference in performance among the culture protocols evaluated in this study. GBS strains isolated from pregnant women appeared to have greater genomic diversity than GBS strains detected in neonates/infants with invasive GBS infections. To confirm this result, further studies with larger sample sizes are needed.

Group B Streptococcus CRISPR1 Typing of Maternal, Fetal, and Neonatal Infectious Disease Isolates Highlights the Importance of CC1 in In Utero Fetal Death

We performed a descriptive analysis of group B Streptococcus (GBS) isolates responsible for maternal and fetal infectious diseases from 2004 to 2020 at the University Hospital of Tours, France. This represents 115 isolates, including 35 isolates responsible for early-onset disease (EOD), 48 isolates responsible for late-onset disease (LOD), and 32 isolates from maternal infections. Among the 32 isolates associated with maternal infection, 9 were isolated in the context of chorioamnionitis associated with in utero fetal death. Analysis of neonatal infection distribution over time highlighted the decrease in EOD since the early 2000s, while LOD incidence has remained relatively stable. All GBS isolates were analyzed by sequencing their CRISPR1 locus, which is an efficient way to determine the phylogenetic affiliation of strains, as it correlates with the lineages defined by multilocus sequence typing (MLST). Thus, the CRISPR1 typing method allowed us to assign a clonal complex (CC) to all isolates; among these isolates, CC17 was predominant (60/115, 52%), and the other main CCs, such as CC1 (19/115, 17%), CC10 (9/115, 8%), CC19 (8/115, 7%), and CC23 (15/115, 13%), were also identified. As expected, CC17 isolates (39/48, 81.3%) represented the majority of LOD isolates. Unexpectedly, we found mainly CC1 isolates (6/9) and no CC17 isolates that were responsible for in utero fetal death. Such a result highlights the possibility of a particular role of this CC in in utero infection, and further investigations should be conducted on a larger group of GBS isolated in a context of in utero fetal death. IMPORTANCE Group B Streptococcus is the leading bacterium responsible for maternal and neonatal infections worldwide, also involved in preterm birth, stillbirth, and fetal death. In this study, we determined the clonal complex of all GBS isolates responsible for neonatal diseases (early- and late-onset diseases) and maternal invasive infections, including chorioamnionitis associated with in utero fetal death. All GBS was isolated at the University Hospital of Tours from 2004 to 2020. We described the local group B Streptococcus epidemiology, which confirmed national and international data concerning neonatal disease incidence and clonal complex distribution. Indeed, neonatal diseases are mainly characterized by CC17 isolates, especially in late-onset disease. Interestingly, we identified mainly CC1 isolates responsible for in utero fetal death. CC1 could have a particular role in this context, and such a result should be confirmed on a larger group of GBS isolated from in utero fetal death.

Interspecies Interactions within the Host: the Social Network of Group B Streptococcus

Group B Streptococcus (GBS) is a pervasive neonatal pathogen accounting for a combined half a million deaths and stillbirths annually. The most common source of fetal or neonatal GBS exposure is the maternal microbiota. GBS asymptomatically colonizes the gastrointestinal and vaginal mucosa of 1 in 5 individuals globally, although its precise role in these niches is not well understood. To prevent vertical transmission, broad-spectrum antibiotics are administered to GBS-positive mothers during labor in many countries. Although antibiotics have significantly reduced GBS early-onset neonatal disease, there are several unintended consequences, including an altered neonatal microbiota and increased risk for other microbial infections. Additionally, the incidence of late-onset GBS neonatal disease remains unaffected and has sparked an emerging hypothesis that GBS-microbe interactions in developing neonatal gut microbiota may be directly involved in this disease process. This review summarizes our current understanding of GBS interactions with other resident microbes at the mucosal surface from multiple angles, including clinical association studies, agriculture and aquaculture observations, and experimental animal model systems. We also include a comprehensive review of in vitro findings of GBS interactions with other bacterial and fungal microbes, both commensal and pathogenic, along with newly established animal models of GBS vaginal colonization and in utero or neonatal infection. Finally, we provide a perspective on emerging areas of research and current strategies to design microbe-targeting prebiotic or probiotic therapeutic intervention strategies to prevent GBS disease in vulnerable populations.

Infection prevention for extremely low birth weight infants in the NICU

Extremely preterm infants are particularly vulnerable to systemic infections secondary to their immature immune defenses, prolonged hospitalizations, delays in enteral feeding, early antibiotic exposure, and need for life-sustaining invasive interventions. There have been several evidence-based practices for infection prevention in this population, such as human milk feedings, utilization of "bundle checklists" and decolonization of pathogenic organisms. Other practices, such as the use of probiotics, human milk-derived fortifiers, and antifungal prophylaxis are more controversial and require further investigation regarding the risks and benefits of such interventions. This chapter examines the susceptibility of the preterm newborn infant to invasive infections and describes several strategies for infection prevention, along with the associated limitations of such practices. It also addresses the various gaps in our understanding of preventing infections in this population, and the need for additional large multi-center randomized controlled trials. Additionally, the role of the SARs-CoV-2 global pandemic and associated strategies for infection prevention in the NICU are discussed.

Prevalence of Group B Streptococcus Recto-Vaginal Colonization, Vertical Transmission, and Antibiotic Susceptibility Among Pregnant Women in Ethiopia: A Systematic Review and Meta-Analysis

Background

Maternal Group B Streptococcus (GBS) recto-vaginal colonization is the most common route for early onset neonatal GBS diseases. A good understanding of the rate of maternal GBS colonization, vertical transmission rate, and antibiotic susceptibility profiles is needed to formulate a broad protection mechanism, like vaccine preparation. For that reason, this meta-analysis aimed at determining the pooled prevalence of GBS recto-vaginal colonization, vertical transmission rate, and antibiotic susceptibility profiles in Ethiopia.

Methods

Both published and unpublished studies were searched from MEDLINE/PubMed, CINAHL (EBSCO), Embase, Cochrane Library, SCOPUS, Web of Sciences databases, and Google Scholar. Independent selection was then carried out by the authors based on the eligibility criteria and data extraction using Microsoft excel. The authors then used STATA version 14.1 software for further cleaning and analysis. The review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses) PRISMA guidelines. Using the random-effect model, the prevalence with a 95% confidence interval (CI) and forest plot were used to present the findings. Besides, the studies' heterogeneity was assessed using Cochrane chi-square (I2) statistics, while Egger intercept was used to assess publication bias.

Results

This review included nineteen studies. The pooled prevalence of recto-vaginal colonization was 15% (95% CI: 11, 19), while the prevalence of vertical transmission was 51% (95% CI: 45, 58) and highest-level susceptibility to vancomycin was 99% (95% CI: 98, 100). However, the GBS susceptibility to tetracycline was 23% (95% CI: 9, 36).

Conclusions

Nearly one out of seven pregnant women in Ethiopia had recto-vaginal colonization of GBS. As a result, half of the pregnancies end with vertical transmission of GBS. Hence, the review emphasizes that policy and programs should consider planning and implementing prophylactic programs.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021287540.

Understanding Factors in Group B Streptococcus Late-Onset Disease

Group B streptococcus (GBS) infection remains a leading cause of sepsis, pneumonia, and meningitis in infants. Rates of GBS early onset disease have declined following the widcespread use of intrapartum antibiotic prophylaxis; hence, late-onset infections (LOGBS) are currently a common presentation of neonatal GBS dicsease. The pathogenesis, mode of transmission, and risk factors associated with LOGBS are unclear, which interfere with effective prevention efforts. GBS may be transmitted from the mother to the infant at the time of delivery or during the postpartum period via contaminated breast milk, or as nosocomial or community-acquired infection. Maternal GBS colonization, prematurity, young maternal age, HIV exposure, and ethnicity (Black) are identified as risk factors for LOGBS disease; however, further studies are necessary to confirm additional risk factors, if any, for the implementation of effective prevention strategies. This narrative review discusses current and previous studies that have reported LOGBS. Few well-designed studies have described this condition; therefore, reliable assessment of maternal GBS colonization, breastfeeding, and twin delivery as risk factors for LOGBS remains limited.

Estimation of country-level incidence of early-onset invasive Group B Streptococcus disease in infants using Bayesian methods

Neonatal invasive disease caused by Group B Streptococcus (GBS) is responsible for much acute mortality and long-term morbidity. To guide development of better prevention strategies, including maternal vaccines that protect neonates against GBS, it is necessary to estimate the burden of this condition globally and in different regions. Here, we present a Bayesian model that estimates country-specific invasive GBS (iGBS) disease incidence in children aged 0 to 6 days. The model combines different types of epidemiological data, each of which has its own limitations: GBS colonization prevalence in pregnant women, risk of iGBS disease in children born to GBS-colonized mothers and direct estimates of iGBS disease incidence where available. In our analysis, we present country-specific maternal GBS colonization prevalence after adjustment for GBS detection assay used in epidemiological studies. We then integrate these results with other epidemiological data and estimate country-level incidence of iGBS disease including in countries with no studies that directly estimate incidence. We are able to simultaneously estimate two key epidemiological quantities: the country-specific incidence of early-onset iGBS disease, and the risk of iGBS disease in babies born to GBS-colonized women. Overall, we believe our method will contribute to a more comprehensive quantification of the global burden of this disease, inform cost-effectiveness assessments of potential maternal GBS vaccines and identify key areas where data are necessary.

Invasive disease caused by Group B Streptococcus (GBS) in young infants continues to be a major public health problem in both developed and developing countries. However, data on the incidence of this infection during the first week of life are only available for a small number of countries, which has complicated the quantification of the burden of this disease globally. In this paper, we develop a Bayesian framework to estimate the incidence of invasive GBS infection that combines data from multiple types of epidemiological studies, with adjustment for relevant factors such as diagnostic methods used in the studies. We present estimates from a series of models, and our results highlight the potential weaknesses of different types of studies and the importance to consider the entire evidence when estimating global burden of invasive neonatal infections. We believe this model is a step toward better quantification of the number of cases in different regions.

Epidemiological Characteristics and Drug Resistance Analysis of Cerebrospinal Fluid Microbial Infections in Wenzhou Area

Objective

Central nervous system infections (CNSI) are serious diseases that endanger human health. Identifying pathogens and their susceptibility to antibiotics, and promptly using antibiotics under this guidance is essential for treatment. The purpose of this study is to investigate the pathogen characteristics of CNSI patients, which can help clinicians choose appropriate empiric antibiotic .

Methods

We retrospectively collected data on CNSI patients with cerebrospinal fluid (CSF) culture positive from 2012 to 2020, including demographic characteristics, laboratory data, pathogenic bacteria, and antimicrobial susceptibility test results.

Results

A total of 166 patients with 168 isolates out of 8188 patients were available for data analysis. Among the isolates, Gram-positive bacteria, Gram-negative bacteria and fungi accounted for 59.5%, 36.3%, and 4.2%, respectively. Among newborns, children under 12, and patients over 12, the most isolated strains were Streptococcus agalactiae (24/46, 52.2%), Streptococcus pneumoniae (21/68, 30.9%) and Staphylococcus epidermidis (10/54, 18.5%), respectively. Streptococcus agalactiae is more sensitive to linezolid and vancomycin. Streptococcus pneumoniae is more sensitive to vancomycin. Staphylococcus epidermidis is more sensitive to clindamycin and rifampicin. The sugar content in the CSF of Gram-negative bacteria of children ≤12 years old was significantly lower than that of Gram-positive bacteria (P<0.05).

Conclusion

We comprehensively studied the etiological characteristics and antimicrobial resistance patterns of positive cerebrospinal fluid cultures in Wenzhou City, Zhejiang Province from 2012 to 2020, which can provide valuable strategies for preventing pathogens and improving evidence-based treatment.

Group B Streptococcus and the vaginal microbiome among pregnant women: a systematic review

BACKGROUND

Vaginal microbiome studies frequently report diversity metrics and communities of microbiomes associated with reproductive health outcomes. Reports of Streptococcus agalactiae (also known as Group B Streptococcus or GBS), the leading cause of neonatal infectious morbidity and mortality, are notably lacking from the studies of the vaginal microbiome, despite being a known contributor to preterm birth and other complications. Therefore, the purpose of this systematic review was to explore the frequency of GBS reporting in vaginal microbiome literature pertaining to pregnancy and to examine methodological bias that contributes to differences in species and genus-level microbiome reporting. Lack of identification of GBS via sequencing-based approaches due to methodologic or reporting bias may result incomplete understanding of bacterial composition during pregnancy and subsequent birth outcomes.

METHODOLOGY

A systematic review was conducted following the PRISMA guideline. Three databases (PubMed, CINAHL, and Web of Science) were used to identify papers for review based on the search terms "vaginal microbiome", "pregnancy", and "16S rRNA sequencing". Articles were evaluated for methods of DNA extraction and sequencing, 16S region, taxonomy classification database, number of participants or vaginal specimens, and pregnancy trimester.

RESULTS

Forty-five research articles reported employing a metagenomic approach or 16S approach for vaginal microbiome analysis during pregnancy that explicitly reported taxonomic composition and were included in this review. Less than 30% of articles reported the presence of GBS (N = 13). No significant differences in methodology were identified between articles that reported versus did not report GBS. However, there was large variability across research methods used for vaginal microbiome analysis and species-level bacterial community reporting.

CONCLUSION

Considerable differences in study design and data formatting methods may contribute to underrepresentation of GBS, and other known pathogens, in existing vaginal microbiome literature. Previous studies have identified considerable variation in methodology across vaginal microbiome studies. This study adds to this body of work because in addition to laboratory or statistical methods, how results and data are shared (e.g., only analyzing genus level data or 20 most abundant microbes), may hinder reproducibility and limit our understanding of the influence of less abundant microbes. Sharing detailed methods, analysis code, and raw data may improve reproducibility and ability to more accurately compare microbial communities across studies.

Prevalence of group B streptococcal colonization in the healthy non-pregnant population: a systematic review and meta-analysis

BACKGROUND

Colonization and transmission precede invasive group B streptococcal (GBS) disease. Data on GBS colonization prevalence, detection methods and risk factors for carriage are relevant for vaccine development and to understand GBS pathogenesis.

OBJECTIVES

To evaluate GBS colonization prevalence after the first week of life in the healthy non-pregnant population.

DATA SOURCES

Pubmed/Medline, Embase, Latin American and Caribbean Health Sciences Literature, World Health Organization Library Information System, and Scopus. Search performed 12 January 2021 with search terms related to 'GBS' and 'colonization, epidemiology, prevalence or screening' without restrictions.

STUDY ELIGIBILITY CRITERIA

All studies that reported prevalence of GBS colonization (any site) in the healthy population.

PARTICIPANTS

All individuals (>6 days of age), with no indication of pregnancy, invasive disease or severe underlying immunological co-morbidities.

METHODS

Logit transformation and a random effects model (DerSimonian and Laird) were used to pool colonization estimates. Subgroup analysis and meta-regression on a priori determined subgroups were performed.

RESULTS

We included 98 studies with 43 112 participants. Our search identified 9309 studies of which 8831 were excluded based on title and abstract and 380 after reading the full text. Colonization rates varied considerably between studies (I² = 97%), which could be partly explained by differences in culture methods (R² = 27%), culture sites (R² = 24%), continent (R² = 10%) and participant's age (R² = 6%). Higher prevalence was found with selective culture methods (19%, 95% CI 16%-23% versus non-selective methods 8%, 95% CI 6%-9%; p < 0.0001). Colonization rates were highest in rectum (19%, 95% CI 15%-24%), vagina (14%, 95% CI 12%-17%) and urethra (9%, 95% CI 5%-18%). In participants with negative rectal cultures, 7% (95% CI 5%-9%) had GBS cultured from another niche. Colonization prevalence was lower in children (6 months to 16 years; 3%, 95% CI 2%-5%) compared with adults (16%, 95% CI 14%-20%; p < 0.0001). Using selective culture methods in adults resulted in a prevalence of 26% (95% CI 19%-33%) rectal, 21% (95% CI 17%-25%) vaginal and 9% (95% CI 6%-14%) urethral colonization.

CONCLUSION

The rectum is the most common body site colonized by GBS. The best approach to screen for any GBS colonization is to screen multiple body sites using selective culture methods.

The burden of neonatal sepsis and its association with antenatal urinary tract infection and intra-partum fever among admitted neonates in Ethiopia: A systematic review and meta-analysis

BACKGROUND

More than one-third of the neonatal death in Ethiopia has been attributed to neonatal sepsis. However, there is no recent national evidence about the burden of neonatal sepsis and its association with antenatal urinary tract infection and intra-partum fever, which are commonly reported maternal morbidities in Ethiopia. Therefore, the aim of this systematic review and meta-analysis was to assess the pooled burden of neonatal sepsis and its association with antenatal urinary tract infection as well as intra-partum fever in the country.

METHODS

Primary studies were accessed through Google scholar, HINARI, SCOPUS and PubMed databases. The methodological and evidence quality of the included studies were critically appraised by the modified Newcastle-Ottawa quality assessment tool scale adapted for observational studies. From eligible studies, two authors extracted author/year, study region, study design, sample size, reported prevalence of neonatal sepsis, antenatal urinary tract infection and intrapartum fever on an excel spreadsheet. During critical appraisal and data extraction, disagreements between the two authors were resolved by the involvement of a third author. The extracted data were then exported to stata version 14. Effect sizes were pooled using the random inverse varience-effects model due to significant heterogeneity between studies (I2= 99.2%). Subgroup analysis was performed for evidence of heterogeneity. Sensitivity analyses were performed. Absence of publication bias was declared from symmetry of funnel plot and Egger's test (p = 0.244).

RESULTS

In this systematic review and meta-analysis, a total of 36,016 admitted neonates were included from 27 studies. Of these 27 studies, 23 employed cross-sectional design whereas 3 studies had case control type and only one study had cohort design. The prevalence of neonatal sepsis among admitted Ethiopian neonates at different regions of the country ranged from 11.7%-77.9%. However, the pooled prevalence of neonatal sepsis was 40.25% [95% CI: 34.00%, 46.50%; I2 = 99.2%]. From regional subgroup analysis, the highest prevalence was observed in the Oromiya region. Neonates born to mothers who had antenatal urinary tract infection were at 3.55 times (95% CI: 2.04, 5.06) higher risk of developing neonatal sepsis as compared to those neonates born to mothers who didn't have antenatal urinary tract infection. Moreover, neonates born to mothers having intra-partum fever were 3.63 times (95% CI: 1.64, 5.62) more likely to develop neonatal sepsis as compared to those born to mothers who were nonfebrile during intrapartum.

CONCLUSION

Neonatal sepsis has remained a problem of public health importance in Ethiopia. Both antenatal urinary tract infection and intra-partum fever were positively associated with neonatal sepsis. Therefore, preventing maternal urinary tract infection during pregnancy and optimizing the intra-partum care are recommended to mitigate the burden of neonatal sepsis in Ethiopia.

Vaccines for Perinatal and Congenital Infections-How Close Are We?

Congenital and perinatal infections are transmitted from mother to infant during pregnancy across the placenta or during delivery. These infections not only cause pregnancy complications and still birth, but also result in an array of pediatric morbidities caused by physical deformities, neurodevelopmental delays, and impaired vision, mobility and hearing. Due to the burden of these conditions, congenital and perinatal infections may result in lifelong disability and profoundly impact an individual's ability to live to their fullest capacity. While there are vaccines to prevent congenital and perinatal rubella, varicella, and hepatitis B infections, many more are currently in development at various stages of progress. The spectrum of our efforts to understand and address these infections includes observational studies of natural history of disease, epidemiological evaluation of risk factors, immunogen design, preclinical research of protective immunity in animal models, and evaluation of promising candidates in vaccine trials. In this review we summarize this progress in vaccine development research for Cytomegalovirus, Group B Streptococcus, Herpes simplex virus, Human Immunodeficiency Virus, Toxoplasma, Syphilis, and Zika virus congenital and perinatal infections. We then synthesize this evidence to examine how close we are to developing a vaccine for these infections, and highlight areas where research is still needed.

Association of sexually-transmitted infection and African-American race with Streptococcus agalactiae colonization in pregnancy

Background

Group B Streptococcus (GBS) remains a significant cause of neonatal infection, but the maternal risk factors for GBS colonization remain poorly defined. We hypothesized that there may be an association between antibiotic exposure during pregnancy and GBS colonization and/or the presence of inducible clindamycin resistance (iCLI-R) in GBS isolates from GBS-colonized pregnant women.

Methods

A retrospective cohort study was performed at Louisiana State University Health Sciences Center – Shreveport including demographic and clinical data from 1513 pregnant women who were screened for GBS between July 1, 2009 and December 31, 2010.

Results

Among 526 (34.8%) women who screened positive for GBS, 124 (23.6%) carried GBS strains with iCLI-R (GBS-iCLI-R). While antibiotic exposure, race, sexually-transmitted infection (STI) in pregnancy, GBS colonization in prior pregnancy and BMI were identified as risk factors for GBS colonization in univariate analyses, the only independent risk factors for GBS colonization were African–American race (AOR = 2.142; 95% CI = 2.092–3.861) and STI during pregnancy (AOR = 1.309; 95% CI = 1.035–1.653). Independent risk factors for GBS-iCLI-R among women colonized with GBS were non-African–American race (AOR = 2.13; 95% CI = 1.20–3.78) and younger age (AOR = 0.94; 95% CI = 0.91–0.98). Among GBS-colonized women with an STI in the current pregnancy, the only independent risk factor for iCLI-R was Chlamydia trachomatis infection (AOR = 4.31; 95% CI = 1.78–10.41).

Conclusions

This study identified novel associations for GBS colonization and colonization with GBS-iCLI-R. Prospective studies will improve our understanding of the epidemiology of GBS colonization during pregnancy and the role of antibiotic exposure in alterations of the maternal microbiome.

Streptococcus agalactiae in childbearing age immigrant women in Comunitat Valenciana (Spain)

Streptococcus agalactiae (GBS) remains the leading cause of meningitis and neonatal sepsis in the world, and causes disease in pregnant and puerperal women. This is a retrospective study of GBS infections on women of childbearing age living in Comunitat Valenciana, Spain (years 2009-2014) and GBS colonization rate on pregnant women attending Hospital La Fe (years 2013-2015) according to their origin. An aggregated total of 6,641,960 women exposed during the study period had an average GBS isolation rate of 5.19‰ (5.14-5.25‰), geographical group rates being: Western Europe (2.2‰), North America (2.1‰), Australia (3.7‰), Spain (4.6‰), Latin America II (4.5‰), Eastern Europe (5.3‰), Asia (6.7‰), Latin America I (7.7‰), Middle East (7.9‰), Indian Subcontinent (17.2‰), North Africa (17.8‰), Sub-Saharan Africa (22.7‰). The 4532 pregnant women studied had an average GBS colonization rate of 12.47% (11.51-13.43) and geographical group rates varied similar to geographical isolation rates. Low GDP and high temperatures of the birth country were associated with higher colonization rates. Thus, differences in GBS colonization depend on the country of origin; Africa and the Indian subcontinent presented the highest, while Western Europe and North America had the lowest. This variability portrays a geographical pattern influenced by temperature and GDP.

Mucosal Vaccination with Lactococcus lactis-Secreting Surface Immunological Protein Induces Humoral and Cellular Immune Protection against Group B Streptococcus in a Murine Model

Group B Streptococcus (GBS) is the primary etiological agent of sepsis and meningitis in newborns and is associated with premature birth and stillbirth. The development of a licensed vaccine is one of the pending challenges for the World Health Organization. Previously, we showed that oral immunization with surface immune protein (SIP) decreases vaginal colonization of GBS and generates functional opsonizing antibodies, which was determined by opsonophagocytic assays (OPA) in vitro. We also showed that the protein has an adjuvant vaccine profile. Therefore, an oral vaccine based on SIP may be an attractive alternative to employ in the development of new vaccines against GBS. Lactococcus lactis is a highlighted oral vaccine probiotic inducer of the mucosal immune response. This bacterium could serve as an antigen-delivering vehicle for the development of an edible vaccine and has been used in clinical trials. In this study, we showed that an oral vaccine with a recombinant L. lactis strain secreting SIP from GBS (rL. lactis-SIP) can induce protective humoral and cellular immunity in an experimental model of GBS vaginal colonization in C57BL/6 mice. Mice immunized with rL. lactis-SIP were protected against clinical symptoms and bacterial colonization after GBS vaginal colonization. Our rL. lactis-SIP vaccine also induces an increase of immunoglobulin G (IgG) and immunoglobulin A (IgA) specifically against SIP. The adoptive transfer of serum from vaccinated mice to naïve mice generated protection against GBS vaginal colonization. Moreover, the rL.lactis-SIP strain induces the activation of SIP-specific T cells, which could decrease GBS vaginal colonization and generate protective antibodies when transferred to other mice. Our experimental observations strongly support the notion that rL. lactis-SIP induces protective humoral and cellular immunity and could be considered as a novel alternative in the development of vaccines for GBS.

Intrapartum beta-lactam antibiotics for preventing group B streptococcal early-onset disease: can we abandon the concept of 'inadequate' intrapartum antibiotic prophylaxis?

Introduction: Neonatal sepsis remains a serious and potentially fatal illness. Intrapartum antibiotic prophylaxis (IAP) prevents group B streptococcal (GBS) early-onset sepsis. The optimal duration of IAP (adequate IAP) to reduce vertical transmission of GBS has been debated. Understanding the mechanism of action of IAP may help in minimizing neonatal evaluation and unnecessary antibiotic use.Areas covered: In recent years, several studies on pharmacokinetics and clinical use of IAP have been published. Although penicillin and ampicillin are the most preferred antibiotics, the clinical efficacy of non-beta-lactam antibiotics, including clindamycin and vancomycin, used in cases of penicillin anaphylaxis-associated allergy, remains debatable. This is a narrative review of the literature regarding the impact of 'inadequate' IAP on the clinical management of women and newborns.Expert opinion: Recent evidence suggests that 'inadequate' IAP with beta-lactams is more effective in preventing vertical transmission of GBS than previously thought. Newborns exposed to intrapartum beta-lactams and who are asymptomatic at birth are likely uninfected, irrespective of IAP duration before delivery. Hence, we may abandon the concept of 'inadequate' IAP with beta-lactams in early-onset GBS sepsis, relying primarily on clinical signs observed at birth for managing IAP-exposed neonates.

Emerging serotype III sequence type 17 group B streptococcus invasive infection in infants: the clinical characteristics and impacts on outcomes

BACKGROUND

Group B Streptococcus (GBS) is an important pathogen that causes high mortality and morbidity in young infants. However, data on clinical manifestations between different GBS serotypes and correlation with molecular epidemiology are largely incomplete. The aim of this study was to determine the serotype distribution, antimicrobial resistance, clinical features and molecular characteristics of invasive GBS isolates recovered from Taiwanese infants.

METHODS

From 2003 to 2017, 182 non-duplicate GBS isolates that caused invasive disease in infants less than one year of age underwent serotyping, multilocus sequence typing (MLST) and antibiotic susceptibility testing. The clinical features of these infants with GBS disease were also reviewed.

RESULTS

Of the 182 patients with invasive GBS disease, 41 (22.5%) were early-onset disease, 121 (66.5%) were late-onset disease and 20 (11.0%) were late late-onset disease (> 90 days of age). All these patients were treated with effective antibiotics on time. Among them, 51 (28.0%) had meningitis, 29 (16.0%) had neurological complications, 12 (6.6%) died during hospitalization, and 15 (8.8%) out of 170 patients who survived had long-term neurological sequelae at discharge. Serotype III GBS strains accounted for 64.8%, followed by serotype Ia (18.1%) and Ib (8.2%). MLST analysis revealed 11 different sequence types among the 182 isolates and ST-17 was the most dominant sequence type (56.6%). The correlation between serotype III and ST17 was evident, as ST17 accounted for 87.3% of all serotype III isolates. There was an obvious increasing trend of type III/ST-17 GBS that caused invasive disease in infants. All isolates were susceptible to penicillin, cefotaxime, and vancomycin, while 68.1 and 65.9% were resistant to erythromycin and clindamycin, respectively.

CONCLUSIONS

Despite timely and appropriate antibiotic treatment, a significant proportion of invasive GBS disease still inevitably causes adverse outcomes. Further study to explore preventive strategies and development of serotype-based vaccines will be necessary in the future.

Characterization of group B Streptococcus colonization in full-term and Late-Preterm neonates in Taiwan

BACKGROUND

Group B streptococcus (GBS) infections can be life-threatening in newborns. This study aimed to analyze GBS carriage status and genotypic diversity in healthy neonates after implementation of intrapartum antibiotic prophylaxis (IAP) in Taiwan.

METHODS

Newborns carrying GBS were identified from a screen of 500 newborns and followed up until their cultures turned negative. Their mothers' GBS screening data were reviewed. Molecular methods, including capsular serotyping, multilocus sequence typing and pulsed-field gel electrophoresis (PFGE), were used to analyze GBS isolates.

RESULTS

GBS colonization was detected at either the nose or anus in 11 of 500 healthy neonates (2.2%). In this group of 11 neonates, 4 had GBS serotypes II and III for 4-6 months, 1 had serotype V for 2 months, 6 had serotypes Ia, II, V, and VI for less than 1 month, and 1 had 2 different serotypes (serotypes V and II) at different times. The most prevalent serotype was II (33.3%), followed by Ia (25.0%), III (16.7%), V (16.7%), and VI (8.3%). The main sequence type was ST1 (50.0%), followed by ST19 (16.7%), ST23 (8.3%), ST24 (8.3%), ST103 (8.3%), and ST 231 (8.3%). All isolates were grouped into 5 PFGE clusters F, G, J, X, and Y, and all were susceptible to β-lactam antimicrobial agents.

CONCLUSIONS

GBS was carried in 2.2% (11/500) healthy newborns and persisted for 6 months in 3 neonates. This study makes clearer our understanding of GBS colonization, serotype distribution, and genotype distribution in healthy neonates.

Prevalence of colonisation by group B streptococcus in pregnant patients in Taguatinga, Federal District, Brazil: a cross-sectional study

PROPOSE

Group B streptococcus is responsible for severe infections in neonates resulting from vertical transmission from pregnant women colonized in the anal, perineal or vaginal regions. The identification of colonized patients and use of intrapartum prophylaxis may reduce the risk of neonatal infection.

METHODS

A cross-sectional study of pregnant women of gestational age between 35 and 37 weeks was conducted. Material was collected from patients for laboratory identification of group B streptococcus. Epidemiological data, including weight, height, body mass index, antibiotic use during pregnancy, pathologies during pregnancy (diabetes, hypertensive diseases, and hypothyroidism), twinning, and others, were also collected from patients.

RESULTS

The sample consisted of 501 pregnant women, and the prevalence of group B streptococcus was 14%. The mean age was 29 years, and the mean BMI was 30.7. During pregnancy, 204 patients had some type of infection, and 201 used antibiotics. Ninety-five patients were diagnosed with gestational diabetes mellitus and 74 with some type of hypertensive disease.

CONCLUSIONS

The prevalence of group B streptococcus observed did not differ from that observed in other studies. None of the factors studied can be considered as risk or protective factors for maternal colonization by group B streptococcus.

Perinatal Streptococcus agalactiae Epidemiology and Surveillance Targets

Streptococcus agalactiae, or group B streptococcus (GBS), is a major neonatal pathogen. Recent data have elucidated the global prevalence of maternal and neonatal colonization, but gaps still remain in the epidemiology of this species. A number of phenotypic and genotypic classifications can be used to identify the diversity of GBS strains, and some are more discriminatory than others. This review explores the main schemes used for GBS epidemiology and further details the targets for epidemiological surveillance. Current screening practices across the world provide a unique opportunity to gain detailed information on maternal colonizing strains and neonatal disease-causing strains, which is vital for monitoring and therapeutics, if sufficient detail can be extracted. Deciphering which isolates are circulating within specific populations and recording targets within invasive strains are crucial steps in monitoring the implementation of therapeutics, such as vaccines, as well as developing novel therapies against prevalent GBS strains. Having a detailed understanding of global GBS epidemiology will prove invaluable for understanding the pathogenesis of this organism and equipping future prevention strategies for success.

Group B streptococcal colonization in mothers and infants in western China: prevalences and risk factors

BACKGROUND

The epidemiology of maternal and infant Group B streptococcus (GBS) colonization is poorly understood in China. The aim of this study is to explore the prevalence and risk factors associated with maternal and infant GBS colonization in Western China.

METHODS

From January 2017 to June 2017, a prospective study was conducted to estimate the maternal and infant GBS colonization rate by maternal rectovaginal and infant nasopharynx, ear canal and umbilical swab culture. Patient demographics, clinical characteristics and outcomes were collected. Chi-square and logistic regression analyses were used to examine the risk factors associated with GBS colonization of mothers and infants.

RESULTS

The GBS colonization rate in mothers and infants was 6.1 and 0.7%, respectively. The vertical transmission rate was 7.6%. The early onset GBS infection rate was 0.58 per 1000 live births and mortality was 0.29 per 1000 live births. Age younger than 40 years (p = 0.040) and minority ethnic status (p = 0.049) were associated with higher GBS colonization rate in pregnant women. Positive GBS status in the mother prior to delivery (p < 0.001) as well as longer duration of membrane rupture (≥12 h) (p < 0.001) and longer labor (≥4 h) (p < 0.001) were all significant risk factors for GBS colonization in infants. Compared to infants without GBS colonization, infants colonized with GBS were more likely to have had a temperature of ≥38 °C (p < 0.001), developed early onset infection (EOD) (p < 0.001), and been prescribed antibiotics (p < 0.001). Furthermore, infants with GBS were more likely to have been admitted to neonatal intensive unit (NICU) (p < 0.001) with a longer hospital length of stay (LOS) (p < 0.001).

CONCLUSIONS

Maternal GBS colonization, longer duration of membrane rupture and labor were all major risk factors associated with GBS colonization in Chinese infants. Infant GBS colonization was associated with increased risk of EOD and NICU admission as well as longer LOS.

Vertical transmission of group B Streptococcus and associated factors among pregnant women: a cross-sectional study, Eastern Ethiopia

Background

Vertically transmitted group B Streptococcus (GBS) causes fetal and neonatal infections. However, there is limited information on the vertical transmission of GBS in low-income countries. This study, therefore, aimed to determine the rate of vertical transmission of GBS and associated factors among pregnant women in Eastern Ethiopia.

Subjects and methods

A cross-sectional, facility-based study was conducted among pregnant women in Harar town, Eastern Ethiopia, from June to October, 2016. GBS positivity of pregnant women was confirmed by culture of rectovaginal swab. Vertical transmission at birth was confirmed by culture on swabs taken from the ear canal, umbilicus, axilla, groin, and nose within 6 hours after birth. Prevalence ratio (PR) along with 95% CI was estimated to examine factors associated with vertical transmission using log binomial regression analysis.

Results

Out of 231 GBS-colonized pregnant women at delivery, 104 births were identified as GBS colonized with a vertical transmission rate of 45.02% and 95% CI: 38.49, 51.68. Of 104 vertical transmission cases, 65 (62.50%) received no intrapartum antibiotic prophylaxis (IAP), 28 (26.92%) received it <4 hours before delivery, and 11 (10.58%) received it ≥4 hours before delivery. Pre-labor rupture of membranes at term (PR: 1.93; 95% CI: 1.04, 3.57), prolonged rupture of the membrane ≥18 hours (PR: 1.76; 95% CI: 1.13, 2.74), intrapartum maternal fever (PR: 1.40; 95% CI: 1.13, 1.75), and IAP received ≥4 hours (PR: 0.17; 95% CI: 0.09, 0.30) were significantly associated with vertical transmission of GBS.

Conclusion

The magnitude of vertical transmission of GBS was very high. However, the rate of adequate IAP received by mothers was very low. Efforts need to be strengthened to screen pregnant women during antenatal care and IAP should be used as necessary. Furthermore, maternal vaccination may provide a feasible strategy to reduce the vertical transmission.

Are postnatal ampicillin levels actually related to the duration of intrapartum antibiotic prophylaxis prior to delivery? A pharmacokinetic study in 120 neonates

OBJECTIVE

To assess ampicillin levels according to the duration of intrapartum antibiotic prophylaxis (IAP).

DESIGN

Prospective cohort single-centre study.

SETTING

Tertiary care centre (Modena, Italy).

PATIENTS

120 neonates≥35 weeks' gestation exposed to IAP.

INTERVENTIONS

Neonates were divided into four groups, according to the duration of IAP prior to delivery: group 1 (n=30; <1 hour), group 2 (n=30; ≥1 and <2 hours), group 3 (n=30; ≥2 and <4 hours) and group 4 (n=30; ≥2 doses, ≥4 hours).

MAIN OUTCOME MEASURES

Blood samples were collected at delivery (from the umbilical cord) and at age 4 hours (from a peripheral vessel).

RESULTS

Median duration of IAP was 121 min (range 7-2045 min). Median ampicillin levels in umbilical cord blood were 10.4 µg/mL (IQR 6.4-14.9) and in peripheral blood were 4.7 µg/mL (IQR 2.8-6.4µg/mL). Umbilical cord blood levels reached a peak approximately 30 min after IAP and then declined significantly (p<0.001). Peripheral blood levels did not differ among study groups. Neonates exposed to a full loading dose (n=115) had peripheral blood levels 2.5-70 times higher than the minimal inhibitory concentration for group B streptococcus. There was no relationship between neonatal ampicillin concentrations and the duration of IAP prior to delivery (β=-0.0003, 95% CI -0.02 to 0.001, p=0.680).

CONCLUSIONS

Ampicillin levels reach a peak in the umbilical cord blood within 30 min of intrapartum administration. After a full loading dose, bactericidal levels persist for at least 4 hours after birth and seem independent of the duration of IAP prior to delivery.

Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches

Group B Streptococcus (GBS) colonizes the gastrointestinal and vaginal epithelium of a significant percentage of healthy women, with potential for ascending intrauterine infection or transmission during parturition, creating a risk of serious disease in the vulnerable newborn. This review highlights new insights on the bacterial virulence determinants, host immune responses, and microbiome interactions that underpin GBS vaginal colonization, the proximal step in newborn infectious disease pathogenesis. From the pathogen perspective, the function GBS adhesins and biofilms, β-hemolysin/cytolysin toxin, immune resistance factors, sialic acid mimicry, and two-component transcriptional regulatory systems are reviewed. From the host standpoint, pathogen recognition, cytokine responses, and the vaginal mucosal and placental immunity to the pathogen are detailed. Finally, the rationale, efficacy, and potential unintended consequences of current universal recommended intrapartum antibiotic prophylaxis are considered, with updates on new developments toward a GBS vaccine or alternative approaches to reducing vaginal colonization.

A novel one-step real-time multiplex PCR assay to detect Streptococcus agalactiae presence and serotypes Ia, Ib, and III

Streptococcus agalactiae is the leading cause of early-onset neonatal sepsis. Culture-based screening methods lack the sensitivity of molecular assays and do not indicate serotype; a potentially important virulence marker. We aimed to develop a multiplex PCR to detect S. agalactiae while simultaneously identifying serotypes Ia, Ib, and III; commonly associated with infant disease. Primers were designed to target S. agalactiae serotype-specific cps genes and the dltS gene. The assay was validated with 512 vaginal specimens from pregnant women. 112 (21.9%) were dltS positive, with 14.3%, 0.9%, and 6.3% of these identified as cps Ia, Ib, and III, respectively. Our assay is a specific and sensitive method to simultaneously detect S. agalactiae and serotypes Ia, Ib, and III in a single step. It is of high significance for clinical diagnostic applications and also provides epidemiological data on serotype, information that may be important for vaccine development and other targeted non-antibiotic therapies.

Group B streptococcal infections in the newborn infant and the potential value of maternal vaccination

Group B Streptococcus (GBS) is a leading cause of neonatal bacterial infections in developed countries. Early-onset disease (EOD) occurs at day 0-6 and late-onset disease occurs at day 7-89. Currently, the prevention of EOD relies upon intrapartum antibiotic prophylaxis (IAP) given to women who are GBS positive at prenatal screening or women with risk factors for EOD. Although successfully implemented, IAP has not fully eradicated EOD, and incidence rates of late-onset disease remain unchanged. Furthermore, antibiotic resistance may result from widespread antibiotic use. New prophylactic strategies are therefore of critical importance. A vaccine active against GBS, administered during pregnancy and combined with targeted IAP, could overcome these problems and reduce the mortality and morbidity associated with invasive diseases.

Maternal group B Streptococcus and the infant gut microbiota

Early patterns of gut colonization may predispose children to adult disease. Exposures in utero and during delivery are associated with the infant gut microbiome. Although ~35% of women carry group B strep (GBS; Streptococcus agalactiae) during pregnancy, it is unknown if GBS presence influences the infant gut microbiome. As part of a population-based, general risk birth cohort, stool specimens were collected from infant's diapers at research visits conducted at ~1 and 6 months of age. Using the Illumina MiSeq (San Diego, CA) platform, the V4 region of the bacterial 16S rRNA gene was sequenced. Infant gut bacterial community compositional differences by maternal GBS status were evaluated using permutational multivariate analysis of variance. Individual operational taxonomic units (OTUs) were tested using a zero-inflated negative binomial model. Data on maternal GBS and infant gut microbiota from either 1 (n=112) or 6-month-old stool (n=150) specimens was available on 262 maternal-child pairs. Eighty women (30.5%) were GBS+, of who 58 (72.5%) were given intrapartum antibiotics. After adjusting for maternal race, prenatal antifungal use and intrapartum antibiotics, maternal GBS status was statistically significantly associated with gut bacterial composition in the 6 month visit specimen (Canberra R 2=0.008, P=0.008; Unweighted UniFrac R 2=0.010, P=0.011). Individual OTU tests revealed that infants of GBS+ mothers were significantly enriched for specific members of the Clostridiaceae, Ruminococcoceae, and Enterococcaceae in the 6 month specimens compared with infants of GBS- mothers. Whether these taxonomic differences in infant gut microbiota at 6 months lead to differential predisposition for adult disease requires additional study.

Characteristics of neonates with culture-proven bloodstream infection who have low levels of C-reactive protein (≦10 mg/L)

Background

Elevated C-reactive protein (CRP) level is widely used in clinical practice as a marker to distinguish between neonates with or without sepsis. However, some neonates with bacteremia have a CRP level within the normal range and they are not well characterized.

Methods

All episodes of neonatal culture-proven bloodstream infections (BSIs) between July 2004 and June 2012 were enrolled. Patients characteristics were compared for three CRP groups (low, ≤ 10 mg/L; intermediate, 11–100 mg/L; and high, > 100 mg/L) using the Chi-square test and one-way ANOVA. The sepsis-attributable mortality rates were compared using logistic regression analyses.

Results

Of 986 episodes of neonatal BSI, 247 (25.1 %) had CRP ≤10 mg/L at the onset of clinical sepsis. In the low CRP group, patients had lower gestational age and birth weight, and an earlier occurrence of BSI. Patients with underlying gastrointestinal pathology, renal disorders, cholestasis, and pulmonary hypertension had a non-significant elevated CRP level at the onset of sepsis. In the blood culture of the low CRP group, coagulase-negative staphylococci (CoNS) were relatively more common (55.9 %, p < 0.001) than the other two groups, although one-fourth were infected with gram-negative bacilli (19.0 %), fungi (2.8 %), or polymicrobial pathogens (3.6 %). Of the BSIs with initial low CRP, 29.1 % were treated with inadequate antibiotics, 13.0 % progressed to septic shock, and 5.3 % had infectious complications. The sepsis-attributable mortality rate was lower in the low CRP group (4.9 %) than in the high CRP group (13.6 %).

Conclusions

A considerable proportion of neonatal BSIs had a normal or low initial CRP level (≤10 mg/L), which was more likely to occur in low birth weight or extremely preterm infants, those with earlier onset of sepsis, and those infected with CoNS. Plasma CRP level should not be used to rule out severe culture-proven sepsis or guide the empirical choice of antibiotics.

Streptococcus salivarius K12 Limits Group B Streptococcus Vaginal Colonization

Streptococcus agalactiae (group B streptococcus [GBS]) colonizes the rectovaginal tract in 20% to 30% of women and during pregnancy can be transmitted to the newborn, causing severe invasive disease. Current routine screening and antibiotic prophylaxis have fallen short of complete prevention of GBS transmission, and GBS remains a leading cause of neonatal infection. We have investigated the ability of Streptococcus salivarius, a predominant member of the native human oral microbiota, to control GBS colonization. Comparison of the antibacterial activities of multiple S. salivarius strains by use of a deferred-antagonism test showed that S. salivarius strain K12 exhibited the broadest spectrum of activity against GBS. K12 effectively inhibited all GBS strains tested, including disease-implicated isolates from newborns and colonizing isolates from the vaginal tract of pregnant women. Inhibition was dependent on the presence of megaplasmid pSsal-K12, which encodes the bacteriocins salivaricin A and salivaricin B; however, in coculture experiments, GBS growth was impeded by K12 independently of the megaplasmid. We also demonstrated that K12 adheres to and invades human vaginal epithelial cells at levels comparable to GBS. Inhibitory activity of K12 was examined in vivo using a mouse model of GBS vaginal colonization. Mice colonized with GBS were treated vaginally with K12. K12 administration significantly reduced GBS vaginal colonization in comparison to nontreated controls, and this effect was partially dependent on the K12 megaplasmid. Our results suggest that K12 may have potential as a preventative therapy to control GBS vaginal colonization and thereby prevent its transmission to the neonate during pregnancy.