Burden of Invasive Group B Streptococcus Infection Among Omani Infants Less Than 90 Days Old: A Multicenter Study

BACKGROUND

Group B Streptococcus (GBS) infection is the leading cause of neonatal morbidity and mortality worldwide. This study aims to investigate the incidence of invasive GBS disease among infants less than 90 days old in Oman and to describe their risk factors, clinical presentations and clinical outcomes.

METHODS

We retrospectively collected the data of less than 90-day-old Omani infants with culture-positive GBS from sterile samples. This study was conducted in 3 tertiary hospitals in Oman from 2009 to 2018.

RESULTS

Over 10 years, we identified 92 cases of culture-confirmed invasive GBS infection from 178,285 live births in the 3 hospitals, giving an overall incidence of 0.53 per 1000 live births [95% confidence interval (CI): 0.4-0.7)]. Of those, 59 (64.1%) had early-onset neonatal GBS disease and 33 (35.9%) had late-onset neonatal GBS disease. The incidence of invasive GBS disease was significantly higher in the last 5 years from 2014 to 2018 (0.69 per 1000 live births, 95% CI: 0.5-0.9) compared to the previous years from 2009 to 2013 (0.36 per 1000 live births, 95% CI: 0.2‒0.5), ( P = 0.004). Infants with late-onset neonatal GBS disease had a higher risk of meningitis compared to infants with early-onset neonatal GBS disease (30.3% vs. 10.2%, P = 0.021). The mortality rate was 13.5%.

CONCLUSIONS

The incidence of invasive GBS disease in Oman is similar to what was reported worldwide, however, the burden of the disease in terms of mortality is high. In addition, a significant increase in the annual incidence of invasive GBS disease in Omani infants was found over the study period.

In Vitro, In Vivo, and In Silico Activities of Ginkgolic Acid C15:1 against Streptococcus agalactiae Clinical Isolates

Streptococcus agalactiae is the major cause of invasive neonatal infections and is a recognized pathogen associated with various diseases in nonpregnant adults. The emergence and spread of antibiotic-resistant S. agalactiae necessitate the development of a novel antibacterial agent. Here, the potential antibacterial activities and mechanisms of ginkgolic acid C15:1 (GA (15:1)) from Ginkgo biloba against clinical S. agalactiae are characterized. The MIC50 and MIC90 values for GA (15:1) against 72 clinical S. agalactiae isolates were 6.25 and 12.5 μM, respectively. GA (15:1) showed a strong bactericidal effect against both planktonic bacteria and bacteria embedded in biofilms as well as significant effectiveness in suppressing the growth of S. agalactiae biofilms. Moreover, GA (15:1) possesses intracellular antibacterial activity and could significantly decrease the bacterial burden in the intraperitoneal infection model of S. agalactiae. Mechanistic studies showed that GA (15:1) triggers membrane damage of S. agalactiae through a unique dual-targeting mechanism of action (MoA). First, GA (15:1) targets phospholipids in the bacterial cytoplasmic membrane. Second, by using mass-spectrometry-based drug affinity responsive target stability (DARTS) and molecular docking, lipoprotein signaling peptidase II (lspA) was identified as a target protein of GA (15:1), whose role is crucial for maintaining bacterial membrane depolarization and permeabilization. Our findings suggest a potential therapeutic strategy for developing GA (15:1) to combat S. agalactiae infections.

Neonatal invasive disease caused by Streptococcus agalactiae in Europe: the DEVANI multi-center study

PURPOSE

Group B streptococcus (GBS) remains a leading cause of invasive disease, mainly sepsis and meningitis, in infants < 3 months of age and of mortality among neonates. This study, a major component of the European DEVANI project (Design of a Vaccine Against Neonatal Infections) describes clinical and important microbiological characteristics of neonatal GBS diseases. It quantifies the rate of antenatal screening and intrapartum antibiotic prophylaxis among cases and identifies risk factors associated with an adverse outcome.

METHODS

Clinical and microbiological data from 153 invasive neonatal cases (82 early-onset [EOD], 71 late-onset disease [LOD] cases) were collected in eight European countries from mid-2008 to end-2010.

RESULTS

Respiratory distress was the most frequent clinical sign at onset of EOD, while meningitis is found in > 30% of LOD. The study revealed that 59% of mothers of EOD cases had not received antenatal screening, whilst GBS was detected in 48.5% of screened cases. Meningitis was associated with an adverse outcome in LOD cases, while prematurity and the presence of cardiocirculatory symptoms were associated with an adverse outcome in EOD cases. Capsular-polysaccharide type III was the most frequent in both EOD and LOD cases with regional differences in the clonal complex distribution.

CONCLUSIONS

Standardizing recommendations related to neonatal GBS disease and increasing compliance might improve clinical care and the prevention of GBS EOD. But even full adherence to antenatal screening would miss a relevant number of EOD cases, thus, the most promising prophylactic approach against GBS EOD and LOD would be a vaccine for maternal immunization.

Pathogens Identified by Minimally Invasive Tissue Sampling in India and Pakistan From Preterm Neonatal Deaths: The PURPOSE Study

BACKGROUND

We identified pathogens found in internal organs and placentas of deceased preterm infants cared for in hospitals in India and Pakistan.

METHODS

Prospective, observational study conducted in delivery units and neonatal intensive care units. Tissue samples from deceased neonates obtained by minimally invasive tissue sampling and placentas were examined for 73 different pathogens using multiplex polymerase chain reaction (PCR).

RESULTS

Tissue for pathogen PCR was obtained from liver, lung, brain, blood, cerebrospinal fluid, and placentas from 377 deceased preterm infants. Between 17.6% and 34.1% of each type of tissue had at least 1 organism identified. Organism detection was highest in blood (34.1%), followed by lung (31.1%), liver (23.3%), cerebrospinal fluid (22.3%), and brain (17.6%). A total of 49.7% of the deceased infants had at least 1 organism. Acinetobacter baumannii was in 28.4% of the neonates compared with 14.6% for Klebsiella pneumoniae, 11.9% for Escherichia coli/Shigella, and 11.1% for Haemophilus influenzae. Group B streptococcus was identified in only 1.3% of the neonatal deaths. A. baumannii was rarely found in the placenta and was found more commonly in the internal organs of neonates who died later in the neonatal period. The most common organism found in placentas was Ureaplasma urealyticum in 34% of the samples, with no other organism found in >4% of samples.

CONCLUSIONS

In organ samples from deceased infants in India and Pakistan, evaluated with multiplex pathogen PCR, A. baumannii was the most commonly identified organism. Group B streptococcus was rarely found. A. baumannii was rarely found in the placentas of these deceased neonates.

Pathogen Distribution and Antimicrobial Resistance of Early Onset Sepsis in Very Premature Infants: A Real-World Study

INTRODUCTION

Early onset sepsis (EOS) remains a potentially fatal newborn condition, especially in very preterm infants. Data on the pathogen distribution and antibiotic susceptibility patterns of EOS among very preterm infants are scarce but essential for the choice of empirical antibiotic administration. We sought to assess the epidemiologic characteristics and antibiotic susceptibility patterns of pathogens causing EOS among a cohort of very preterm infants in China.

METHODS

This prospective, observational study included a cohort of infants born at a gestational age (GA) less than 32 weeks of 32 newborn intensive care units (NICUs) in China between January 1, 2018 and December 31, 2020. EOS was defined by isolation of pathogenic species from blood culture within 72 h of birth.

RESULTS

A total of 108 EOS cases (18.4 per 1000 admissions) were identified among 5865 very preterm infants. Incidence of EOS increased with the decrease of GA and birthweight. Escherichia coli (n = 44, 40.7%) was the most common pathogen, followed by Klebsiella spp. (n = 10, 9.3%). The distribution and proportion of pathogenic bacteria varied significantly by GA. E. coli and Klebsiella spp. showed high resistance to ampicillin and third-generation cephalosporins, while they showed good susceptibility to carbapenem antibiotics and piperacillin-tazobactam.

CONCLUSION

Our data demonstrated that pathogens causing neonatal EOS showed high rates of resistance to ampicillin and third-generation cephalosporins. This raised questions about the best empirical antibiotic choice for preterm infants suspected of having EOS in low- and middle-income countries (LMICs).

Group B streptococcus infection during pregnancy and infancy: estimates of regional and global burden

BACKGROUND

Group B streptococcus (GBS) colonisation during pregnancy can lead to invasive GBS disease (iGBS) in infants, including meningitis or sepsis, with a high mortality risk. Other outcomes include stillbirths, maternal infections, and prematurity. There are data gaps, notably regarding neurodevelopmental impairment (NDI), especially after iGBS sepsis, which have limited previous global estimates. In this study, we aimed to address this gap using newly available multicountry datasets.

METHODS

We collated and meta-analysed summary data, primarily identified in a series of systematic reviews published in 2017 but also from recent studies on NDI and stillbirths, using Bayesian hierarchical models, and estimated the burden for 183 countries in 2020 regarding: maternal GBS colonisation, iGBS cases and deaths in infants younger than 3 months, children surviving iGBS affected by NDI, and maternal iGBS cases. We analysed the proportion of stillbirths with GBS and applied this to the UN-estimated stillbirth risk per country. Excess preterm births associated with maternal GBS colonisation were calculated using meta-analysis and national preterm birth rates.

FINDINGS

Data from the seven systematic reviews, published in 2017, that informed the previous burden estimation (a total of 515 data points) were combined with new data (17 data points) from large multicountry studies on neurodevelopmental impairment (two studies) and stillbirths (one study). A posterior median of 19·7 million (95% posterior interval 17·9-21·9) pregnant women were estimated to have rectovaginal colonisation with GBS in 2020. 231 800 (114 100-455 000) early-onset and 162 200 (70 200-394 400) late-onset infant iGBS cases were estimated to have occurred. In an analysis assuming a higher case fatality rate in the absence of a skilled birth attendant, 91 900 (44 800-187 800) iGBS infant deaths were estimated; in an analysis without this assumption, 58 300 (26 500-125 800) infant deaths from iGBS were estimated. 37 100 children who recovered from iGBS (14 600-96 200) were predicted to develop moderate or severe NDI. 40 500 (21 500-66 200) maternal iGBS cases and 46 200 (20 300-111 300) GBS stillbirths were predicted in 2020. GBS colonisation was also estimated to be potentially associated with considerable numbers of preterm births.

INTERPRETATION

Our analysis provides a comprehensive assessment of the pregnancy-related GBS burden. The Bayesian approach enabled coherent propagation of uncertainty, which is considerable, notably regarding GBS-associated preterm births. Our findings on both the acute and long-term consequences of iGBS have public health implications for understanding the value of investment in maternal GBS immunisation and other preventive strategies.

FUNDING

Bill & Melinda Gates Foundation.

Early-Onset Neonatal Sepsis in Low- and Middle-Income Countries: Current Challenges and Future Opportunities

Neonatal sepsis is defined as a systemic infection within the first 28 days of life, with early-onset sepsis (EOS) occurring within the first 72h, although the definition of EOS varies in literature. Whilst the global incidence has dramatically reduced over the last decade, neonatal sepsis remains an important cause of neonatal mortality, highest in low- and middle-income countries (LMICs). Symptoms at the onset of neonatal sepsis can be subtle, and therefore EOS is often difficult to diagnose from clinical presentation and laboratory testing and blood cultures are not always conclusive or accessible, especially in resource limited countries. Although the World Health Organisation (WHO) currently advocates a ß-lactam, and gentamicin for first line treatment, availability and cost influence the empirical antibiotic therapy administered. Antibiotic treatment of neonatal sepsis in LMICs is highly variable, partially caused by factors such as cost of antibiotics (and who pays for them) and access to certain antibiotics. Antimicrobial resistance (AMR) has increased considerably over the past decade and this review discusses current microbiology data available in the context of the diagnosis, and treatment for EOS. Importantly, this review highlights a large variability in data availability, methodology, availability of diagnostics, and aetiology of sepsis pathogens.

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.

The effect of group B streptococcus on maternal and infants' prognosis in Guizhou, China

Group B Streptococcus (GBS) is a kind of opportunistic pathogenic bacteria and mainly strikes the lower digestive tract and genitourinary tract. It is a major risk factor for neonatal babies, seriously threatening their lives. In the present study, we aimed to detect the GBS colonization in late pregnant women, and to study the effect of GBS on maternal and infants’ prognosis. Pregnant women with a gestational age of 35–37 weeks were enrolled in the study. Real-time polymerase chain-reaction (RT-PCR) was used to detect the colonization of GBS in the vaginal and rectal secretions for late pregnant women according to the screening guidelines. Chi-square test was applied to analyze the relationship between GBS colonization and clinical characteristics. A follow-up of 6 weeks was performed on the puerpera and infants after delivery. The positive rate of GBS was 12.6% in late pregnant women. GBS carrier state was positively related to several pregnancy outcomes, including intrauterine infection, premature rupture of membranes, postpartum hemorrhage, fetal distress and puerperal infection, as well as to part neonatal outcomes, containing neonatal infection, neonatal pneumonia and neonatal sepsis (all P < 0.05). GBS infection in late pregnant women results in adverse effects on maternal and neonatal outcomes.

Neonatal sepsis: within and beyond China

Sepsis remains a significant cause of neonatal morbidity and mortality in China. A better understanding of neonatal sepsis in China as compared with other industrialized and non-industrialized countries may help optimize neonatal health care both regionally and globally. Literature cited in this review was retrieved from PubMed using the keywords "neonatal sepsis," "early-onset (EOS)" and "late-onset (LOS)" in English, with the focus set on population-based studies. This review provides an updated summary regarding the epidemiology, pathogen profile, infectious work-up, and empirical treatment of neonatal sepsis within and beyond China. The incidence of neonatal EOS and the proportion of Group B Streptococcus (GBS) within pathogens causing EOS in China seem to differ from those in developed countries, possibly due to different population characteristics and intrapartum/postnatal health care strategies. Whether to adopt GBS screening and intrapartum antibiotic prophylaxis in China remains highly debatable. The pathogen profile of LOS in China was shown to be similar to other countries. However, viruses as potential pathogens of neonatal LOS have been underappreciated. Growing antimicrobial resistance in China reflects limitations in adapting antibiotic regimen to local microbial profile and timely cessation of treatment in non-proven bacterial infections. This review stresses that the local epidemiology of neonatal sepsis should be closely monitored in each institution. A prompt and adequate infectious work-up is critically important in diagnosing neonatal sepsis. Adequate and appropriate antibiotic strategies must be overemphasized to prevent the emergence of multi-resistant bacteria in China.

Pathogenesis and in vivo interactions of human Streptococcus agalactiae isolates in the Galleria mellonella invertebrate model

Group B Streptococcus (GBS) is a gram positive bacterium colonizing the gastrointestinal and urogenital tracts in humans. However under certain conditions GBS invades leading to severe infections in neonates, pregnant women, immunocompromised patients and the elderly people. The precise mechanisms involved in the transition from colonizer to pathogen remain to be elucidated, however it has been suggested that environmental determinants may regulate gene expression resulting in GBS invasion. We have assessed the potential of the moth Galleria mellonella as a model to study the in vivo virulence and GBS interactions of invasive and noninvasive human isolates from our population. Temperature, pH and bacterial competition effects were examined in the model as well as the response of Galleria hemocytes to GBS infection. GBS strains were able to effectively grow and infect G. mellonella in a dose dependent manner with a (half-lethal dose) LD₅₀ 1 × 10⁷ CFU after 24 h. GBS infection induced larva melanization with hemocyte vacuolation and depletion. Larval killing increased with environmental conditions such as temperature (37 °C) and pH (≥5.5-7.2). Bacterial interference assays showed a remarkable antagonistic effect of Lactobacillus gasseri (cells and filtrates) on GBS infection and significantly improved Galleria survival. The protective effect of L. gasseri was observed even at ratios similar to those of GBS colonization suggesting that L. gasseri modulation by its metabolic products is relevant. Exposure to L. gasseri acidic filtrates induced growth inhibition and prevented larva killing after infection with the hypervirulent GBS clone (a multiresistant clinical ST 17 strain). We showed that mechanisms mediating these effects are mainly pH dependent, however other mechanisms may have a role depending on inocula. We also found that G. mellonella infected with invasive human GBS isolates showed differential killing curves with higher killing rates after 24 h when compared to those considered colonizers or noninvasive isolates. Overall it has been shown that G. mellonella may be a representative in vivo model for baseline GBS studies. Given the potential effects over the hypervirulent strain, our findings support the use of L. gasseri in the GBS control strategies based on Lactobacillus formulations.

Pan-GWAS of Streptococcus agalactiae Highlights Lineage-Specific Genes Associated with Virulence and Niche Adaptation

GBS is a leading cause of mortality in newborn babies in high- and low-income countries worldwide. Different strains of GBS are characterized by different degrees of virulence, where some are harmlessly carried by humans or animals and others are much more likely to cause disease. The genome sequences of almost 2,000 GBS samples isolated from both animals and humans in high- and low- income countries were analyzed using a pan-genome-wide association study approach. This allowed us to identify 279 genes which are associated with different lineages of GBS, characterized by a different virulence and preferred host. Additionally, we propose that the GBS now carried in humans may have first evolved in animals before expanding clonally once adapted to the human host. These findings are essential to help understand what is causing GBS disease and how the bacteria have evolved and are transmitted.

Streptococcus agalactiae (group B streptococcus; GBS) is a colonizer of the gastrointestinal and urogenital tracts, and an opportunistic pathogen of infants and adults. The worldwide population of GBS is characterized by clonal complexes (CCs) with different invasive potentials. CC17, for example, is a hypervirulent lineage commonly associated with neonatal sepsis and meningitis, while CC1 is less invasive in neonates and more commonly causes invasive disease in adults with comorbidities. The genetic basis of GBS virulence and the extent to which different CCs have adapted to different host environments remain uncertain. We have therefore applied a pan-genome-wide association study (GWAS) approach to 1,988 GBS strains isolated from different hosts and countries. Our analysis identified 279 CC-specific genes associated with virulence, disease, metabolism, and regulation of cellular mechanisms that may explain the differential virulence potential of particular CCs. In CC17 and CC23, for example, we have identified genes encoding pilus, quorum-sensing proteins, and proteins for the uptake of ions and micronutrients which are absent in less invasive lineages. Moreover, in CC17, carriage and disease strains were distinguished by the allelic variants of 21 of these CC-specific genes. Together our data highlight the lineage-specific basis of GBS niche adaptation and virulence.

The genome sequences of almost 2,000 GBS samples isolated from both animals and humans in high- and low- income countries were analyzed using a pan-genome-wide association study approach. This allowed us to identify 279 genes which are associated with different lineages of GBS, characterized by a different virulence and preferred host. Additionally, we propose that the GBS now carried in humans may have first evolved in animals before expanding clonally once adapted to the human host.

These findings are essential to help understand what is causing GBS disease and how the bacteria have evolved and are transmitted.

Clinical and Molecular Epidemiology of Invasive Group B Streptococcus Disease among Infants, China

Invasive group B Streptococcus (GBS) remains a leading cause of illness and death among infants globally. We conducted prospective and retrospective laboratory-based surveillance of GBS-positive cultures from infants <3 months of age in 18 hospitals across China during January 1, 2015-December 31, 2017. The overall incidence of GBS was 0.31 (95% CI 0.27-0.36) cases/1,000 live births; incidence was 0-0.76 cases/1,000 live births across participating hospitals. The case-fatality rate was 2.3%. We estimated 13,604 cases of GBS and 1,142 GBS-associated deaths in infants <90 days of age annually in China. GBS isolates were most commonly serotype III (61.5%) and clonal complex 17 (40.6%). Enhanced active surveillance and implementation of preventive strategies, such as maternal GBS vaccination, warrants further investigation in China to help prevent these infections.

Aetiology of invasive bacterial infection and antimicrobial resistance in neonates in sub-Saharan Africa: a systematic review and meta-analysis in line with the STROBE-NI reporting guidelines

BACKGROUND

Aetiological data for neonatal infections are essential to inform policies and programme strategies, but such data are scarce from sub-Saharan Africa. We therefore completed a systematic review and meta-analysis of available data from the African continent since 1980, with a focus on regional differences in aetiology and antimicrobial resistance (AMR) in the past decade (2008-18).

METHODS

We included data for microbiologically confirmed invasive bacterial infection including meningitis and AMR among neonates in sub-Saharan Africa and assessed the quality of scientific reporting according to Strengthening the Reporting of Observational Studies in Epidemiology for Newborn Infection (STROBE-NI) checklist. We calculated pooled proportions for reported bacterial isolates and AMR.

FINDINGS

We included 151 studies comprising data from 84 534 neonates from 26 countries, almost all of which were hospital-based. Of the 82 studies published between 2008 and 2018, insufficient details were reported regarding most STROBE-NI items. Regarding culture positive bacteraemia or sepsis, Staphylococcus aureus, Klebsiella spp, and Escherichia coli accounted for 25% (95% CI 21-29), 21% (16-27), and 10% (8-10) respectively. For meningitis, the predominant identified causes were group B streptococcus 25% (16-33), Streptococcus pneumoniae 17% (9-6), and S aureus 12% (3-25). Resistance to WHO recommended β-lactams was reported in 614 (68%) of 904 cases and resistance to aminoglycosides in 317 (27%) of 1176 cases.

INTERPRETATION

Hospital-acquired neonatal infections and AMR are a major burden in Africa. More population-based neonatal infection studies and improved routine surveillance are needed to improve clinical care, plan health systems approaches, and address AMR. Future studies should be reported according to standardised reporting guidelines, such as STROBE-NI, to aid comparability and reduce research waste.

FUNDING

Uduak Okomo was supported by a Medical Research Council PhD Studentship.

Genomic Insights Into the Distribution and Evolution of Group B Streptococcus

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a bacteria with truly protean biology. It infects a variety of hosts, among which the most commonly studied are humans, cattle, and fish. GBS holds a singular position in the history of bacterial genomics, as it was the substrate used to describe one of the first major conceptual advances of comparative genomics, the idea of the pan-genome. In this review, I describe a brief history of GBS and the major contributions of genomics to understanding its genome plasticity and evolution as well as its molecular epidemiology, focusing on the three hosts mentioned above. I also discuss one of the major recent paradigm shifts in our understanding of GBS evolution and disease burden: foodborne GBS can cause invasive infections in humans.

Prevalence of group B streptococcus among pregnant women and newborns at Hawassa University comprehensive specialized hospital, Hawassa, Ethiopia

BACKGROUND

Group B streptococcus (GBS) is reported as the leading cause of neonatal sepsis and meningitis. Newborns from GBS colonized pregnant women are at high risk of infection.

METHOD

A Hospital based cross-sectional study was conducted at Hawassa University Comprehensive Specialized Hospital from November 05, 2014 to March 25, 2015. A total of 280 pregnant women along with their newborns were screened for GBS using standard method recommended by Center of Disease Control and Prevention. GBS strains were serotyped by using serotype specific antisera. A structured questionnaire was used to collect sociodemographic, obstetrics and clinical data of pregnant women and newborns. Data was analyzed by using chi-square and logistic regression to determine factors associated with prevalence of GBS among pregnant women and newborns. Descriptive statistics was used to determine prevalence of GBS among pregnant women and newborns. P value less than 0.05 was considered statistically significant.

RESULT

Prevalence of GBS among pregnant women, newborns and vertical transmission rate at Hawassa University Comprehensive Specialized Hospital were 44(15.7%), 26(8.9%) and 59.1% respectively. Among 26 GBS colonized newborns one developed sign and symptoms of early onset disease. Serotype distribution of GBS isolates collected from pregnant women and newborns was Ia 13(18.6%), Ib 9(12.9%), II 24(34.3%), III 8(11.4%), V 14(20%), and NT 2 (2.9%).

CONCLUSION

In our study we found relatively high prevalence of GBS among pregnant women and vertical transmission rate. The most prevalent GBS serotypes identified in this study were serotype II followed by V, Ia and Ib. Therefore, appropriate prevention strategies such as intrapartum antibiotic prophylaxis and vaccine development should be considered.

Baby survival in Zambia: stillbirth and neonatal death in a local hospital setting

Background

Globally, 2.6 million stillbirths occur every year. Of these, 98% occur in developing countries. According to the United Nations Children’s Fund, the neonatal mortality rate in Zambia in 2014 was 2.4%. In 2016, the World Health Organization released the International Classification of Diseases - Perinatal Mortality (ICD-PM) as a globally applicable and comparable system for the classification of the causes of perinatal deaths. However, data for developing countries are scarce. The aim of this study was to evaluate the rates and causes of stillbirths and neonatal deaths at a local hospital in Zimba, Zambia to identify opportunities for preventive interventions.

Methods

All cases of stillbirths and neonatal deaths at Zimba Mission Hospital in Zambia in 2017 were included in this study. Outborn neonates who were transferred to the hospital and later died were also included in the study. Causes of stillbirths and neonatal deaths were analyzed and classified according to ICD-PM.

Results

In total, 1754 babies were born via 1704 deliveries at the hospital, and 28 neonates were transferred to the hospital after birth. The total number of perinatal deaths was 75 (4.2%), with 7 deaths in the antepartum, 25 deaths in the intrapartum, and 43 deaths in the neonatal period. Most antepartum deaths (n = 5; 71.4%) were classified as fetal deaths of unspecified causes. Intrapartum deaths were due to acute intrapartum events (n = 21; 84.0%) or malformations, deformations, or chromosomal abnormalities (n = 4; 16.0%). Neonatal deaths were related primarily to complications from intrapartum events (n = 19; 44.2%); low birth weight or prematurity (n = 16; 37.2%); or infection (n = 3; 7.0%).

Conclusions

Perinatal deaths were associated with acute intrapartum events and considered preventable in 40 cases (53.3%). Effective interventions to prevent perinatal deaths are needed.

Bacterial Infections in Neonates, Madagascar, 2012-2014

Severe bacterial infections are a leading cause of death among neonates in low-income countries, which harbor several factors leading to emergence and spread of multidrug-resistant bacteria. Low-income countries should prioritize interventions to decrease neonatal infections; however, data are scarce, specifically from the community. To assess incidence, etiologies, and antimicrobial drug–resistance patterns of neonatal infections, during 2012–2014, we conducted a community-based prospective investigation of 981 newborns in rural and urban areas of Madagascar. The incidence of culture-confirmed severe neonatal infections was high: 17.7 cases/1,000 live births. Most (75%) occurred during the first week of life. The most common (81%) bacteria isolated were gram-negative. The incidence rate for multidrug-resistant neonatal infection was 7.7 cases/1,000 live births. In Madagascar, interventions to improve prevention, early diagnosis, and management of bacterial infections in neonates should be prioritized.

Is a positive Christie-Atkinson-Munch-Peterson (CAMP) test sensitive enough for the identification of Streptococcus agalactiae?

Background

For a long time, the Christie-Atkinson-Munch-Peterson (CAMP) test has been a standard test for the identification of Streptococcus agalactiae, and a positive result for S.agalactiae has been considered sensitive enough.

Methods

To confirm whether a positive CAMP test is a requirement for the identification of S.agalactiae, five suspected CAMP-negative S.agalactiae isolates from two hospitals, confirmed as Gram-positive and catalase-negative streptococci, were verified by the CAMP test in three batches of plates from two manufacturers and identified by the Phoenix system, MALDI-TOF MS, the PCR assay and the 16S rDNA gene sequencing.

Results

All five suspected strains were S.agalactiae, four of which were CAMP-negative and one of which was not S.agalactiae by the PCR assay.

Conclusions

A positive CAMP test was lacking sensitivity for the identification of S.agalactiae, and the question of whether the cfb gene is worthy of targeting should be further studied.

Changes in the incidence and epidemiology of neonatal group B Streptococcal disease over the last two decades in Crete, Greece

Group B streptococcus (GBS) remains a leading cause of neonatal disease. However, GBS rates and prevention strategies vary considerably worldwide. Herein, we investigated the burden and epidemiological trends of neonatal GBS infections in our area (Greece) over the last two decades. We conducted a multicenter retrospective study that includes all cases of culture-proven GBS disease in infants <90 days old in the last 22 years. Neonatal GBS incidence was 0.17/1000 live births (95%CI: 0.11-0.21). A significant increase was noted during the second decade (0.23 vs 0.10/1000, P<0.05). Late onset disease (LOD) significantly increased during the second decade (0.08 vs 0.02, P<0.05). Infants in the LOD group had a higher risk of meningitis (RR 1.8, 95%CI: 1.23-2.71). Long-term neurological sequelae were reported in 42.8% of meningitis cases. The mortality rate was 8%. The incidence of neonatal GBS disease in our area is among the lowest reported, but an increase was noted the last decade mainly due a rise in the LOD. The burden of LOD, the mortality and long-term disability are still substantial, thus effective prevention strategies − including maternal vaccination for neonatal GBS − are needed.

Group B Streptococcus Serotypes in Pregnant Women From the Western Cape Region of South Africa

Background: Maternal colonization of Group B streptococci (GBS) during pregnancy is an important risk factor for neonatal morbidity and mortality. The aim of this study was to determine the prevalence and serotype distribution of GBS isolated from a cohort of pregnant women in the Western Cape, South Africa. Methods: Two ano-vaginal swabs were collected from 301 women at 28-37 weeks of gestation. Participants were recruited from four different antenatal clinics in the Western Cape, South Africa. GBS were detected by culture and PCR and serotypes confirmed by latex agglutination tests. Antibiotic sensitivity was performed using disc diffusion. Results: The GBS colonization rate was 16.6%. Serotype distribution revealed serotype V as the predominant serotype (66.67%) followed by serotype III (21.05%). Serotypes Ia, II, IV, and IX constituted 1.75% each and 3 GBS isolates were non-typeable. Serotype V demonstrated resistance to most of the antibiotics tested, while serotype III demonstrated better susceptibility, except for tetracycline. No significant differences were observed for GBS colonization or serotype distribution according to HIV status. Conclusion: Predominating serotypes differed from those previously reported from other regions in South Africa. Global surveillance of serotype distribution plays an important role in informing vaccine development and antibiotic prophylaxis.

Assessment of conventional PCR and real-time PCR compared to the gold standard method for screening Streptococcus agalactiae in pregnant women

Group B Streptococcus is a causative agent of invasive neonatal infections. Maternal colonization by Streptococcus agalactiae is a necessary condition for vertical transmission, with efficient screening of pregnant women playing an essential role in the prevention of neonatal infections. In this study, we aimed to compare the performance of conventional polymerase chain reaction and real-time PCR assays as screening methods for S. agalactiae in pregnant women against the microbiological culture method considered as the gold-standard. A total of 130 samples from pregnant women were analyzed for sensitivity, specificity, positive predictive value, and negative predictive value. Statistical analysis was performed using the SPSS software, version 20.0. The verified colonization rate was 3.8% with the gold-standard, 17.7% with conventional PCR assay, and 29.2% with the real-time PCR test. The trials with conventional PCR and real-time PCR had a sensitivity of 100% and a specificity of 85.6% and 73.6%, respectively. The real-time PCR assay had a better performance compared to the gold-standard and a greater detection rate of colonization by S. agalactiae compared to conventional PCR assay. With its quick results, it would be suitable for using in routine screenings, contributing to the optimization of preventive approaches to neonatal S. agalactiae infection.

Aetiology of neonatal sepsis in Nigeria, and relevance of Group b streptococcus: A systematic review

BACKGROUND

Group B Streptococcus (GBS) causes invasive infections in neonates and has been implicated as a cause of prelabour rupture of membranes, preterm delivery and stillbirths. The success of phase II trials of polyvalent polysaccharide GBS vaccines indicates that these infections are potentially preventable. Nigeria is the most populous country in Africa with one of the highest birth rates, one of the highest neonatal sepsis incidence rates and one of the highest mortality rates in the world. Therefore, before the possible introduction of preventive strategies such as intrapartum antibiotic prophylaxis or GBS vaccine into Nigeria, it is vital that there is accurate data on the aetiology of neonatal sepsis and on the incidence of GBS neonatal sepsis in particular. The objective of this study was to determine the incidence and aetiology of neonatal sepsis in Nigeria with a focus on GBS sepsis and also to assess the potential impact of a GBS vaccine.

METHODS

A literature search was conducted on the databases of African journals online, PubMed and Google Scholar for works conducted between 1987 to 2017. Case reports, reviews, and studies not stating specific culture methods or specific bacteria isolated were excluded. Data extracted included; incidence of neonatal sepsis, method of blood culture, blood volume, sample size, bacterial agents isolated and history of antibiotic use. PRISMA guidelines were followed and modified Down's and Black criteria used to evaluate the quality of studies.

RESULTS

A total of 5,114 studies were reviewed for neonatal sepsis out of which 24 consisting of a total of 2,280 cases were selected for final review. Nine studies met criteria for assessment of hospital based incidence of neonatal sepsis representing 31,305 hospital births. The incidence of neonatal sepsis was 18.2/1000 livebirths with range from 7-55/1000 livebirths while the GBS incidence was 0.06/1000 livebirths with range from 0-2/1000 live births. We discovered various limitations such as identification techniques that could result in underestimation of the true incidence of GBS sepsis. Pathogens such as Klebsiella pneumoniae and Staphylococcus aureus were more commonly isolated than GBS.

IMPLICATIONS OF KEY FINDINGS

The hospital based incidence of neonatal sepsis was high at 18.2/1000 live births while that due to GBS was 0.06/1000 live births. The burden of neonatal sepsis, including that attributable to GBS is substantial and could be reduced by preventive strategies such as intrapartum antibiotic prophylaxis or GBS vaccine. There is however very sparse meaningful data currently. Well planned prospective studies with larger sample sizes, more advanced isolation and identification techniques and those following up invasive disease cases for possible short and long term sequelae are needed-not only prior to possible introduction of the vaccine to determine the baseline epidemiology, but also thereafter to monitor its impact on the population. Strategies need to be developed to also reduce the morbidity and mortality attributable to other bacteria that have an incidence even greater than that of GBS.

Prevalence, antimicrobial resistance and serotype distribution of group B streptococcus isolated among pregnant women and newborns in Rabat, Morocco

Purpose. Group B streptococcus (GBS) is an important cause of neonatal sepsis worldwide. Data on the prevalence of maternal GBS colonization, risk factors for carriage, antibiotic susceptibility and circulating serotypes are necessary to tailor adequate locally relevant public health policies.Methodology. A prospective study including pregnant women and their newborns was conducted between March and July 2013 in Morocco. We collected clinical data and vagino-rectal and urine samples from the recruited pregnant women, together with the clinical characteristics of, and body surface samples from, their newborns. Additionally, the first three newborns admitted every day with suspected invasive infection were recruited for a thorough screening for neonatal sepsis. Serotypes were characterized by molecular testing.Results. A total of 350 pregnant women and 139 of their newborns were recruited. The prevalence of pregnant women colonized by GBS was 24 %. In 5/160 additional sick newborns recruited with suspected sepsis, the blood cultures were positive for GBS. Gestational hypertension and vaginal pruritus were significantly associated with a vagino-rectal GBS colonization in univariate analyses. All of the strains were susceptible to penicillin, while 7 % were resistant to clindamycin and 12 % were resistant to erythromycin. The most common GBS serotypes detected included V, II and III.Conclusion. In Morocco, maternal GBS colonization is high. Penicillin can continue to be the cornerstone of intrapartum antibiotic prophylaxis. A pentavalent GBS vaccine (Ia, Ib, II, III and V) would have been effective against the majority of the colonizing cases in this setting, but a trivalent one (Ia, Ib and III) would only prevent 28 % of the cases.

Epidemiology of invasive group B streptococcal disease in infants from urban area of South China, 2011-2014

Background

Group B Streptococcus (GBS) is a leading cause of morbidity and mortality in infants in both developed and developing countries. To our knowledge, only a few studies have been reported the clinical features, treatment and outcomes of the GBS disease in China. The severity of neonatal GBS disease in China remains unclear. Population-based surveillance in China is therefore required.

Methods

We retrospectively collected data of <3 months old infants with culture-positive GBS in sterile samples from three large urban tertiary hospitals in South China from Jan 2011 to Dec 2014. The GBS isolates and their antibiotic susceptibility were routinely identified in clinical laboratories in participating hospitals. Serotyping and multi-locus sequence typing (MLST) were also conducted for further analysis of the neonatal GBS disease.

Results

Total 70 cases of culture-confirmed invasive GBS infection were identified from 127,206 live births born in studying hospitals, giving an overall incidence of 0.55 per 1000 live births (95% confidence interval [CI] 0.44–0.69). They consisted of 49 with early-onset disease (EOD, 0.39 per 1000 live births (95% CI 0.29–0.51)) and 21 with late-onset disease (LOD, 0.17 per 1000 live births (95% CI 0.11–0.25)). The incidence of EOD increased significantly over the studying period. Five infants (4 EOD and 1 LOD) died before discharge giving a mortality rate of 7.1% and five infants (7.1%, 2 EOD and 3 LOD) had neurological sequelae. Within 68 GBS isolates from GBS cases who born in the studying hospitals or elsewhere, serotype III accounted for 77.9%, followed by Ib (14.7%), V (4.4%), and Ia (2.9%). MLST analysis revealed the presence of 13 different sequence types among the 68 GBS isolates and ST-17 was the most frequent sequence type (63.2%). All isolates were susceptible to penicillin, ceftriaxone, vancomycin and linezolid, while 57.4% and 51.5% were resistant to erythromycin and clindamycin, respectively.

Conclusions

This study gains the insight into the spectrum of GBS infection in south China which will facilitate the development of the guidance for reasonable antibiotics usage and will provide evidence for the implementation of potential GBS vaccines in the future.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2811-0) contains supplementary material, which is available to authorized users.

Incidence and serotype characterisation of Streptococcus agalactiae in a Portuguese hospital

AIMS

Streptococcus agalactiae, commonly known as group B Streptococcus (GBS), has been recognised as a worldwide causative pathogenic agent of neonatal sepsis, meningitis and pneumonia. To better understand the behaviour of S. agalactiae in pregnant women from a hospital from the North of Portugal, retrospective analyses were performed to describe epidemiological, clinical and microbiological characteristics of the isolates obtained.

METHODS

Based on laboratorial records and the hospital's patient files, a 6-year retrospective study was performed to analyse S. agalactiae isolates from screened pregnant women between 35 and 37 weeks of gestation and hospitalised neonates from pregnant women between 24 and 41 weeks of gestation admitted in Hospital Pedro Hispano. Serotype characterisation was also performed in 67 GBS strains.

RESULTS

In 6692 pregnant women between 35 and 37 weeks of gestation screened between 2011 and 2016, a total of 1377 S. agalactiae isolates (21%) were found. A high percentage (40%) of unknown colonisation status among hospitalised neonates from pregnant women between 24 and 41 weeks of gestations was also found. The incidence of neonatal sepsis was 8.7 (95% CI 7.0 to 10.8) cases per 1000 live births. Regarding serotype characterisation, serotype III (22.4%) was the most frequent, followed by serotype Ia (19.4%) and serotypes Ib and V (both with 17.9%).

CONCLUSION

High epidemiological values of GBS colonisation and incidence were found in this study. In Portugal studies on the epidemiology and behaviour of S. agalactiae remain limited, reinforcing the importance and need for S. agalactiae screening across the country.

Carriage and serotype distribution of Streptococcus agalactiae in third trimester pregnancy in southern Ghana

BACKGROUND

The aim of this study was to determine the prevalence of Streptococcus agalactiae (group B streptococci, GBS) among healthy, pregnant women attending antenatal care at different study sites in the Greater Accra Region, Ghana.

METHODS

Between 2010 and June 2013, recto-vaginal swab samples were collected from pregnant women attending antenatal care from two study sites in southern Ghana. The samples were collected within 35 and 37 weeks of the gestation period. These were inoculated into Todd-Hewitt broth followed by sub-culturing onto a sheep-blood agar plate. Identification was performed on a single subcultured colony. Gram staining was performed, and isolates were evaluated for beta-haemolytic reactions. Furthermore, the isolates were serotyped using the GBS latex serotyping kit.

RESULTS

The carriage rates were found to be 25.5% (95% CI: 19.6-32.1) to 28.0% (95% CI: 21.9-34.8) for the two collection sites. The most common serotypes were serotypes VII and IX. The data showed that women below 20 years of age or above 30 years of age have a significantly (p = 0.037) higher risk of carrying GBS compared to women from the age group of 20 to 30 years.

CONCLUSIONS

The findings of this study revealed that prevalence of GBS colonization in pregnant women in Greater Accra region is high and comparable to rates observed in South Africa and Western countries. The most prevalent serotypes were serotypes VII and IX, which have not been observed before in West Africa.

Group B streptococcus and respiratory syncytial virus immunisation during pregnancy: a landscape analysis

Group B streptococcus and respiratory syncytial virus are leading causes of infant morbidity and mortality worldwide. No licensed vaccines are available for either disease, but vaccines for both are under development. Severe respiratory syncytial virus disease can be prevented by passively administered antibody. The presence of maternal IgG antibody specific to respiratory syncytial virus is associated with reduced prevalence and severity of respiratory syncytial virus disease in the first few weeks of life, whereas maternal serotype-specific anticapsular antibody is associated with protection against both early-onset and late-onset group B streptococcus disease. Therefore, vaccination in pregnancy might protect infants against both diseases. This report describes what is known about immune protection against group B streptococcus and respiratory syncytial virus, identifies knowledge gaps regarding the immunobiology of both diseases, and aims to prioritise research directions in maternal immunisation.

Group B Streptococcal Colonization Among Pregnant Women in Delhi, India

BACKGROUND

Little is known regarding maternal group B streptococcal (GBS) colonization prevalence and capsular (CPS) serotype distribution among pregnant women in India. The objective of this prospective cohort study was to determine GBS recto-vaginal colonization prevalence in pregnant women at Dr. Ram Manohar Lohia Hospital in Delhi, India.

METHODS

Literature review identified reports from India assessing GBS colonization prevalence in pregnant women. Rectal and vaginal swabs were inoculated into Strep B Carrot Broth (Hardy Diagnostics, Santa Maria, CA) and subcultured onto GBS Detect plates (Hardy Diagnostics, Santa Maria, CA). Isolates were serotyped using ImmuLex Strep-B latex kits (Statens Serum Institut, Copenhagen, Denmark).

RESULTS

Thirteen studies were identified citing GBS colonization prevalence during pregnancy as 0.47%-16%. Among 300 pregnant women (mean age: 26.9 years; mean gestation: 34 weeks) enrolled (August 2015 to April 2016), GBS colonization prevalence was 15%. Fifteen percent of women had vaginal only, 29% had rectal only and 56% had both sites colonized. CPS types were Ia (13.3%), Ib (4.4%), II (20%), III (22.2%), V (20%) and VII (6.7%); 13.3% were nontypable. Fetal loss in a prior pregnancy at ≥20-weeks gestation was more common in colonized than noncolonized women (15.6% vs. 3.5%; P = 0.004). Employing recent census data for the birth cohort and estimating that 1%-2% of neonates born to colonized women develop early-onset disease, at least 39,000 cases of early-onset disease may occur yearly in India.

CONCLUSIONS

Using optimal methods, 15% of third trimester pregnant women in India are GBS colonized. A multivalent vaccine containing 6 CPS types (Ia, Ib, II, III, V and VII) would encompass ~87% of GBS carried by pregnant women in India.

Group B Streptococcus among Pregnant Women and Newborns in Mirzapur, Bangladesh: Colonization, Vertical Transmission, and Serotype Distribution

Group B streptococcus (GBS) infection is a leading cause of death among newborns in developed countries. Data on the burden of GBS in Asian countries are lacking. This study aimed to understand (i) the rate of maternal rectovaginal GBS carriage, (ii) the rate of vertical transmission of GBS, as determined by culturing ear, umbilicus, and nasal swabs, and (iii) the distribution of GBS serotypes. This prospective observational study was conducted between September 2012 and November 2013 at Kumudini Women's Medical College Hospital, a secondary-level hospital in Mirzapur, Bangladesh. The study enrolled pregnant women who visited the outpatient clinic for antenatal care (ANC) and/or delivered a child in the inpatient department of Kumudini Women's Medical College Hospital and the babies born to those mothers. Among 1,151 enrolled pregnant women, 172 (15% [95% confidence interval [CI], 13 to 17%]) carried GBS; among 68 babies born to mothers with carriage, 26 (38% [95% CI, 27 to 51%]) had GBS on their body surfaces, indicating vertical transmission. Typing of the isolates (n = 172) identified all 10 GBS serotypes, most commonly types Ia (40% [69/172 isolates]), V (23% [40/172 isolates]), II (14% [24/172 isolates]), and III (12% [20/172 isolates]). This study shows that Bangladesh has all of the ingredients for invasive GBS disease, including colonization of mothers by invasive serotypes and vertical transmission to babies.

The global health impact of vaginal dysbiosis

The most common dysbiosis of the vaginal microbiome (defined here as a vaginal microbiome not dominated by lactobacilli) is bacterial vaginosis, an anaerobic polybacterial dysbiosis. Other dysbiotic states of importance to global health are vaginal microbiota with a high abundance of streptococci, staphylococci or Enterobacteriaceae, vaginal candidiasis and trichomoniasis. Knowledge about the different types of dysbiosis and their relationship to urogenital and reproductive disease burden has increased in recent years by applying non-culture-based techniques, but is far from complete. The burden of bacterial vaginosis is highest in sub-Saharan Africa and in women of sub-Saharan African descent living elsewhere. Vaginal dysbiosis has been associated with increased susceptibility to and transmission of HIV and other sexually transmitted infections and increased risk of pelvic inflammatory disease, preterm birth and maternal and neonatal infections. In this review, we summarize the contribution of vaginal dysbiosis to the global burden of each of these and highlight areas that require more research.

Group B streptococcal disease in infants in the first year of life: a nationwide surveillance study in Japan, 2011-2015

PURPOSE

This study aimed to describe the epidemiology of childhood group B streptococcus (GBS) disease including late late-onset disease (LLOD) and to clinically characterize recurrent cases and twin-sibling cases in Japan.

METHODS

We collected information on infants (<1 year of age) with invasive GBS disease and institutional information about births and transfers through a nationwide questionnaire between 2011 and 2015.

RESULTS

We identified 133 infants with early-onset disease (EOD), 274 late-onset disease (LOD), and 38 LLOD from 149 institutes. The case fatality rate (CFR) of EOD, LOD, and LLOD was 4.5, 4.4, and 0%, respectively. CFR in EOD was significantly (P < 0.001) associated with preterm birth, but not that in LOD and LLOD. Twenty-nine percent of infants with meningitis (49/169) had neurologic sequelae. We showed clinical details of 12 recurrent cases that accounted for 2.8% of the total patients, and 4 sets of both twins affected; 4 of 12 recurrent cases and 3 of 4 twin-sibling sets were also associated with preterm birth. Based on the livebirth number of 581,488, the instituted-based incidence of EOD, LOD, and LLOD was estimated as 0.09 (95% CI 0.06-0.11), 0.12 (95% CI 0.11-0.14), and 0.01 (95% CI 0.01-0.02) per 1000 livebirths, respectively.

CONCLUSIONS

CFR of EOD and LOD in Japan is comparable with that in high-income European countries or the United States, and their incidence is much lower. Our findings also describe the clinical details of LLOD, recurrent infections, and infections in twin siblings. This study is the largest among Asian childhood GBS studies ever reported.

Challenges in reducing group B Streptococcus disease in African settings

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis in high-income settings and is associated with high rates of neonatal mortality and morbidity. There is now increasing evidence to suggest that there is a high GBS disease burden in resource-limited countries, and it is therefore critically important to identify suitable and practical preventive strategies. In Europe and North America, intrapartum antibiotic prophylaxis (IAP) has led to a dramatic reduction of early-onset GBS disease. However, the methods for identifying pregnant women who should receive IAP and how to reduce late-onset GBS disease are not without controversy and are challenging for most sub-Saharan African countries. GBS vaccines are approaching phase III trials but are still under development. This review aims to explore the current evidence related to strategies for reducing invasive GBS disease in an African setting, the development of a GBS vaccine and whether preventative measures against GBS disease can be practically implemented.

Temporal Changes in Invasive Group B Streptococcus Serotypes: Implications for Vaccine Development

INTRODUCTION

There is a paucity of longitudinal data on the serotype-specific burden of invasive group B Streptococcus (GBS) disease from low-middle income countries, which could inform selection of vaccine epitopes.

METHODS

From 2005 to 2014, infants less than 90 days of age with invasive GBS disease were identified through sentinel laboratory and hospital admission surveillance at Chris Hani Baragwanath Academic Hospital in Soweto, South Africa.

RESULTS

We identified 820 cases of invasive GBS disease, including 55% among newborns <7 days age (i.e. early-onset disease; EOD). The overall incidence (per 1,000 live births) of invasive GBS disease was 2.59 (95% CI: 2.42-2.77), including 1.41 (95% CI: 1.28-1.55) for EOD and 1.18 (95% CI: 1.06-1.30) in infants 7-89 days age (late-onset disease). Year-on-year, from 2005 to 2014, we observed a 9.4% increase in incidence of serotype Ia invasive disease (RR: 1.09; 95% CI: 1.04-1.15; p<0.001), and a 7.4% decline in serotype III invasive disease (RR: 0.93; 95% CI: 0.90-0.96; p<0.001). Overall, serotypes Ia (28.2%), III (55.4%) and V (7.9%) were the commonest disease causing serotypes.

CONCLUSIONS

The incidence of invasive GBS disease has remained persistently high in our setting, with some changes in serotype distribution, albeit mainly involving the same group of dominant serotypes.

Prevalence, Serotype Distribution and Mortality Risk Associated With Group B Streptococcus Colonization of Newborns in Rural Bangladesh

BACKGROUND

Group B Streptococcus (GBS) is a predominant cause of early-onset neonatal sepsis globally; however, the impact of this organism on the health of newborns in South Asia is debated, due in part to a paucity of community-based assessments. We estimated the prevalence and serotypes of GBS colonization of the umbilical cord stump and the association of colonization with mortality in a population-based cohort of newborns in rural Sylhet District, Bangladesh.

METHODS

Umbilical cord swabs were collected from 646 newborns up to 3 times within the first week after birth (ages <24 hours, ~3 days, ~6 days) and processed to identify GBS serotypes.

RESULTS

GBS was isolated from 6.3% (41/646) of newborns. Sixty-one percent of the GBS colonization occurred in neonates within 24 hours of delivery. Serotypes VII (37.1%, n = 13/36) and Ia (33.3%, n = 12/36) were the most predominant colonizing GBS isolates. Other detected serotypes were Ib (11.1%, n = 4/36), II (11.1%, n = 4/36), V (5.6%, n = 2/36) and VI (2.8%, n = 1/36). Mortality risk among newborns with GBS colonization was 6.6 (95% confidence interval: 2.1-20.4) times higher than for those without GBS.

CONCLUSIONS

The overall prevalence of GBS colonization was lower than in settings, where GBS is a predominant etiology of neonatal illness. In addition, the GBS serotype distribution differed from that reported in the developed part of the world. However, further studies are needed to understand the true burden of GBS-related illness. Mortality risk was substantially increased in the presence of GBS on the umbilical stump, providing support for chlorhexidine antisepsis to the cord to prevent colonization of invasive pathogens.

Neonatal bloodstream infections in a Ghanaian Tertiary Hospital: Are the current antibiotic recommendations adequate?

Background

Diagnosis of bloodstream infections (BSI) in neonates is usually difficult due to minimal symptoms at presentation; thus early empirical therapy guided by local antibiotic susceptibility profile is necessary to improve therapeutic outcomes.

Methods

A review of neonatal blood cultures submitted to the microbiology department of the Korle-Bu Teaching Hospital was conducted from January 2010 through December 2013. We assessed the prevalence of bacteria and fungi involved in BSI and the susceptibility coverage of recommended empiric antibiotics by Ghana Standard Treatment guidelines and the WHO recommendations for managing neonatal sepsis. The national and WHO treatment guidelines recommend either ampicillin plus gentamicin or ampicillin plus cefotaxime for empiric treatment of neonatal BSI. The WHO recommendations also include cloxacillin plus gentamicin. We described the resistance profile over a 28-day neonatal period using multivariable logistic regression analysis with linear or restricted cubic splines.

Results

A total of 8,025 neonatal blood culture reports were reviewed over the four-year period. Total blood culture positivity was 21.9 %. Gram positive organisms accounted for most positive cultures, with coagulase negative staphylococci (CoNS) being the most frequently isolated pathogen in early onset infections (EOS) (59.1 %) and late onset infections (LOS) (52.8 %). Susceptibility coverage of early onset bacterial isolates were 20.7 % to ampicillin plus cefotaxime, 32.2 % to the combination of ampicillin and gentamicin, and 71.7 % to cloxacillin plus gentamicin. For LOS, coverage was 24.6 % to ampicillin plus cefotaxime, 36.2 % to the combination ampicillin and gentamicin and 63.6 % to cloxacillin plus gentamicin. Cloxacillin plus gentamicin remained the most active regimen for EOS and LOS after exclusion of BSI caused by CoNS. For this regimen, the adjusted odds of resistance decreased between 12-34 % per day from birth to day 3 followed by the slowest rate of resistance increase, compared to the other antibiotic regimen, thereafter until day 28. The trend in resistance remained generally unchanged after excluding data from CoNS. Multidrug resistant isolates were significantly (p-value <0.001) higher in LOS (62.4 %, n = 555/886) than in EOS (37.3 %, n = 331/886).

Conclusions

There is low antibiotic susceptibility coverage for organisms causing neonatal bloodstream infections in Korle-Bu Teaching Hospital when the current national and WHO recommended empiric antibiotics were assessed. A continuous surveillance of neonatal BSI is required to guide hospital and national antibiotic treatment guidelines for neonatal sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1913-4) contains supplementary material, which is available to authorized users.

Group B Streptococcus vaccine development: present status and future considerations, with emphasis on perspectives for low and middle income countries

Globally, group B Streptococcus (GBS) remains the leading cause of sepsis and meningitis in young infants, with its greatest burden in the first 90 days of life. Intrapartum antibiotic prophylaxis (IAP) for women at risk of transmitting GBS to their newborns has been effective in reducing, but not eliminating, the young infant GBS disease burden in many high income countries. However, identification of women at risk and administration of IAP is very difficult in many low and middle income country (LMIC) settings, and is not possible for home deliveries. Immunization of pregnant women with a GBS vaccine represents an alternate pathway to protecting newborns from GBS disease, through the transplacental antibody transfer to the fetus in utero. This approach to prevent GBS disease in young infants is currently under development, and is approaching late stage clinical evaluation. This manuscript includes a review of the natural history of the disease, global disease burden estimates, diagnosis and existing control options in different settings, the biological rationale for a vaccine including previous supportive studies, analysis of current candidates in development, possible correlates of protection and current status of immunogenicity assays. Future potential vaccine development pathways to licensure and use in LMICs, trial design and implementation options are discussed, with the objective to provide a basis for reflection, rather than recommendations.

Prevalence of maternal colonisation with group B streptococcus: a systematic review and meta-analysis

BACKGROUND

The most important risk factor for early-onset (babies younger than 7 days) invasive group B streptococcal disease is rectovaginal colonisation of the mother at delivery. We aimed to assess whether differences in colonisation drive regional differences in the incidence of early-onset invasive disease.

METHODS

We did a systematic review of maternal group B streptococcus colonisation studies by searching MEDLINE, Embase, Pascal Biomed, WHOLIS, and African Index Medicus databases for studies published between January, 1997, and March 31, 2015, that reported the prevalence of group B streptococcus colonisation in pregnant women. We also reviewed reference lists of selected studies and contacted experts to identify additional studies. Prospective studies in which swabs were collected from pregnant women according to US Centers for Disease Control and Prevention guidelines that used selective culture methods were included in the analyses. We calculated mean prevalence estimates (with 95% CIs) of maternal colonisation across studies, by WHO region. We assessed heterogeneity using the I(2) statistic and the Cochran Q test.

FINDINGS

221 full-text articles were assessed, of which 78 studies that included 73 791 pregnant women across 37 countries met prespecified inclusion criteria. The estimated mean prevalence of rectovaginal group B streptococcus colonisation was 17·9% (95% CI 16·2-19·7) overall and was highest in Africa (22·4, 18·1-26·7) followed by the Americas (19·7, 16·7-22·7) and Europe (19·0, 16·1-22·0). Studies from southeast Asia had the lowest estimated mean prevalence (11·1%, 95% CI 6·8-15·3). Significant heterogeneity was noted across and within regions (all p≤0·005). Differences in the timing of specimen collection in pregnancy, selective culture methods, and study sample size did not explain the heterogeneity.

INTERPRETATION

The country and regional heterogeneity in maternal group B streptococcus colonisation is unlikely to completely explain geographical variation in early-onset invasive disease incidence. The contribution of sociodemographic, clinical risk factor, and population differences in natural immunity need further investigation to understand these regional differences in group B streptococcus maternal colonisation and early-onset disease.

FUNDING

None.

Genomic Analysis Reveals Multi-Drug Resistance Clusters in Group B Streptococcus CC17 Hypervirulent Isolates Causing Neonatal Invasive Disease in Southern Mainland China

Neonatal invasive disease caused by group B Streptococcus (GBS) represents a significant public health care concern globally. However, data related to disease burden, serotype distribution, and molecular epidemiology in China and other Asian countries are very few and specifically relative to confined regions. The aim of this study was to investigate the genetic characteristics of GBS isolates recovered from neonates with invasive disease during 2013–2014 at Guangzhou and Changsha hospitals in southern mainland China. We assessed the capsular polysaccharide type, pilus islands (PIs) distribution and hvgA gene presence in a panel of 26 neonatal clinical isolates, of which 8 were recovered from Early Onset Disease and 18 from Late Onset Disease (LOD). Among 26 isolates examined, five serotypes were identified. Type III was the most represented (15 cases), particularly among LOD strains (n = 11), followed by types Ib (n = 5), V (n = 3), Ia (n = 2) and II (n = 1). We performed whole-genome sequencing analysis and antimicrobial susceptibility testing on the 14 serotype III isolates belonging to the hypervirulent Clonal Complex 17 (serotype III-CC17). The presence of PI-2b alone was associated with 13 out of 14 serotype III-CC17 strains. Genome analysis led us to identify two multi-drug resistance gene clusters harbored in two new versions of integrative and conjugative elements (ICEs), carrying five or eight antibiotic resistance genes, respectively. These ICEs replaced the 16 kb-locus that normally contains the PI-1 operon. All isolates harboring the identified ICEs showed multiple resistances to aminoglycoside, macrolide, and tetracycline antibiotic classes. In conclusion, we report the first whole-genome sequence analysis of 14 GBS serotype III-CC17 strains isolated in China, representing the most prevalent lineage causing neonatal invasive disease. The acquisition of newly identified ICEs conferring multiple antibiotic resistance could in part explain the spread of this specific clone among Chinese neonatal isolates and underlines the need for a constant epidemiological surveillance.

Recognising early onset neonatal sepsis: an essential step in appropriate antimicrobial use

Early diagnosis and timely treatment of early onset neonatal sepsis (EOS) are essential to prevent life threatening complications. Subtle, nonspecific clinical presentation and low predictive values of biomarkers complicate early diagnosis. This uncertainty commonly results in unnecessary and prolonged empiric antibiotic treatment. Annually, approximately 395,000 neonates (7.9% of live term births) are treated for suspected EOS in the European Union, while the incidence of proven EOS varies between 0.01 and 0.53 per 1000 live births. Adherence to guidelines for the management of suspicion of EOS is poor. Pragmatic approaches to minimise overtreatment in neonates with suspected EOS, using combined stratified risk algorithms, based on maternal and perinatal risk factors, clinical characteristics of the neonate and sequential biomarkers are promising.

Invasive Group B Streptococcal Disease in South Africa: Importance of Surveillance Methodology

Data on neonatal group B streptococcal (GBS) invasive disease burden are needed to refine prevention policies. Differences in surveillance methods and investigating for cases can lead to varying disease burden estimates. We compared the findings of laboratory-based passive surveillance for GBS disease across South Africa, and for one of the provinces compared this to a real-time, systematic, clinical surveillance in a population-defined region in Johannesburg, Soweto. Passive surveillance identified a total of 799 early-onset disease (EOD, <7 days age) and 818 LOD (late onset disease, 7-89 days age) cases nationwide. The passive surveillance provincial incidence varied for EOD (range 0.00 to 1.23/1000 live births), and was 0.03 to 1.04/1000 live births for LOD. The passive surveillance rates for Soweto, were not significantly different compared to those from the systematic surveillance (EOD 1.23 [95%CI 1.06-1.43] vs. 1.50 [95%CI 1.30-1.71], respectively, rate ratio 0.82 [95%CI 0.67-1.01]; LOD 1.04 [95% CI 0.90-1.23] vs. 1.22 [95%CI 1.05-1.42], rate ratio 0.85 [95% CI 0.68-1.07]). A review of the few cases missed in the passive system in Soweto, suggested that missing key identifiers, such as date of birth, resulted in their omission during the electronic data extraction process. Our analysis suggests that passive surveillance provides a modestly lower estimate of invasive GBS rates compared to real time sentinel-site systematic surveillance, however, this is unlikely to be the reason for the provincial variability in incidence of invasive GBS disease in South Africa. This, possibly reflects that invasive GBS disease goes undiagnosed due to issues related to access to healthcare, poor laboratory capacity and varying diagnostic procedures or empiric antibiotic treatment of neonates with suspected sepsis in the absence of attempting to making a microbiological diagnosis. An efficacious GBS vaccine for pregnant women, when available, could be used as a probe to better quantify the burden of invasive GBS disease in low-middle resourced settings such as ours. From our study passive systems are important to monitor trends over time as long as they are interpreted with caution; active systems give better detailed information and will have greater representivity when expanded to other surveillance sites.

Streptococcus agalactiae infection in cancer patients: a five-year study

Although the highest burden of Streptococcus agalactiae infections has been reported in industrialized countries, studies on the characterization and epidemiology are still limited in developing countries and implementation of control strategies remains undefined. The aim of this retrospective study was to assess the epidemiological, clinical, and microbiological aspects of S. agalactiae infections in cancer patients treated at a Reference Brazilian National Cancer Institute - INCA, Rio de Janeiro, Brazil. We reviewed the clinical and laboratory records of all cancer patients identified as having invasive S. agalactiae disease during 2010-2014. The isolates were identified by biochemical analysis and tested for antimicrobial susceptibility. A total of 263 strains of S. agalactiae were isolated from cancer patients who had been clinically and microbiologically classified as infected. S. agalactiae infections were mostly detected among adults with solid tumors (94 %) and/or patients who have used indwelling medical devices (77.2 %) or submitted to surgical procedures (71.5 %). Mortality rates (in-hospital mortality during 30 days after the identification of S. agalactiae) related to invasive S. agalactiae infections (n = 28; 31.1 %) for the specific category of neoplasic diseases were: gastrointestinal (46 %), head and neck (25 %), lung (11 %), hematologic (11 %), gynecologic (4 %), and genitourinary (3 %). We also found an increase in S. agalactiae resistance to erythromycin and clindamycin and the emergence of penicillin-less susceptible isolates. A remarkable number of cases of invasive infections due to S. agalactiae strains was identified, mostly in adult patients. Our findings reinforce the need for S. agalactiae control measures in Brazil, including cancer patients.

Status of vaccine research and development of vaccines for GBS

Streptococcus agalactiae (group B streptococcus (GBS)) is the leading cause of neonatal sepsis and meningitis in many countries. Intrapartum antibiotic strategies have reduced the incidence of early-onset neonatal GBS in a number of countries but have had no impact on late onset GBS infection (LOD). In low/middle income settings, the disease burden remains uncertain although in several countries of Southern Africa appears comparable to or higher than that of high-income countries. As disease may be rapidly fulminating cases can be missed before appropriate samples are obtained and this may lead to underestimation of the true burden. Given the rapid onset and progression within hours of birth as well as the deficiencies in IAP strategies and absence of a solution for preventing LOD, it is clear that administration of a suitable vaccine in pregnancy could provide a better solution in all settings; it should also be cost effective. The current leading vaccine candidates are CPS-protein conjugate vaccines but protein-based vaccines are also in development and one has recently commenced clinical trials.

Group B streptococcus vaccination in pregnant women with or without HIV in Africa: a non-randomised phase 2, open-label, multicentre trial

Background

Neonates born to women infected with HIV are at increased risk for invasive group B streptococcus (GBS) disease. We aimed to compare safety and immunogenicity of trivalent glycoconjugate GBS vaccine in pregnant women with and without HIV in Malawi and South Africa.

Methods

In our non-randomised phase 2, open-label, multicentre study, we recruited pregnant women attending two antenatal clinics, one in Blantyre, Malawi, and one in Soweto, Johannesburg, South Africa. Participants were divided into three groups on the basis of their HIV infection status (no infection, infection and high CD4 cell count [>350 cells per μL], and infection and low CD4 cell count [>50 to ≤350 cells per μL]) and received a 5 μg dose of glycoconjugate GBS vaccine (serotypes Ia, Ib, and III, with CRM₁₉₇ [Novartis Vaccines, Siena, Italy]) intramuscularly at 24–35 weeks' gestation. GBS serotype-specific antibody concentrations were measured before vaccination (day 1), day 15, day 31, and at delivery, and in infants at birth and day 42 of life. The primary outcomes were safety in mothers and infants and the amount of placental transfer of GBS serotype-specific antibodies from mothers to their infants. All immunogenicity and safety analyses were done on the full analysis set, including participants who, or whose mother, correctly received the vaccine and who provided at least one valid assessable serum sample. This study is registered with ClinicalTrials.gov, number NCT01412801.

Findings

270 women and 266 infants were enrolled between Sept 26, 2011, and Dec 4, 2012 (90 women and 87 infants without HIV, 89 and 88 with HIV and high CD4 cell counts, and 91 and 91 with HIV and low CD4 cell counts, respectively). Seven women were lost to follow-up, six withdrew consent, one died, and two relocated. Eight infants died or were stillborn and two were lost to follow-up. Across serotypes, fold change in antibody concentrations were higher for the HIV-uninfected group than the HIV-infected groups. Transfer ratios were similar across all three groups (0·49–0·72; transfer ratio is infant geometric mean antibody concentration in blood collected within 72 h of birth divided by maternal geometric mean antibody concentration in blood collected at delivery); however, at birth, maternally derived serotype-specific antibody concentrations were lower for infants born to women infected with HIV (0·52–1·62 μg/mL) than for those born to women not infected with HIV (2·67–3·91 μg/mL). 151 (57%) of 265 women reported at least one solicited adverse reaction: 39 (45%) of 87 women with HIV and low CD4 cell counts, 52 (59%) of 88 women with HIV and high CD4 cell counts, and 60 (67%) of 90 women in the HIV-uninfected group. 49 (18%) of 269 women had at least one adverse event deemed possibly related to the vaccine (six [7%] in the HIV and low CD4 cell count group, 12 [13%] in the HIV and high CD4 cell count group, and 21 [23%] in the HIV-uninfected group), as did three (1%) of 266 neonates (zero, two [1%], and one [1%]); none of these events was regarded as serious.

Interpretation

The vaccine was less immunogenic in women infected with HIV than it was in those not infected, irrespective of CD4 cell count, resulting in lower levels of serotype-specific maternal antibody transferred to infants, which could reduce vaccine protection against invasive GBS disease. A validated assay and correlate of protection is needed to understand the potential protective value of this vaccine.

Funding

Novartis Vaccines and Diagnostics division (now part of the GlaxoSmithKline group of companies), Wellcome Trust UK, Medical Research Council: Respiratory and Meningeal Pathogens Research Unit.