Risk factors for Group B Streptococcus colonisation and disease in Gambian women and their infants

Recurrence of group B streptococcal infections in infants: a systematic review

INTRODUCTION

Group-B Streptococcus(GBS) infections may rarely recur after antibiotic treatment. We aimed to fill existing gaps on epidemiology, clinical features, and outcomes of GBS recurrences.

METHODS

A systematic search of PubMed and Embase was conducted, covering the period until 1 July 2024. The demographics, clinical characteristics, treatment, and outcomes of infants withGBS recurrence were analyzed. Recurrence was defined as > 1 episode of invasiveGBS infection (positive blood and/or cerebrospinal fluid culture), occurring after the completion of treatment for the initial episode.

RESULTS

Among the 213 recurrences, 146 reported individual data and were included in the analysis. GBS recurrences developed shortly after the completion of antibiotic treatment for the initial infection (median = 10 days 95%CI 6.0-18.8). Most infants were preterm (63.5%) and had received an adequately long course of antibiotics for the initial infection (median = 13 days, 95%CI 10-14). Serotype III waspredominant. Breast milk yielded GBS in most samples cultured (41/62, 66%); 5/15 (33%) infants who discontinued breastfeeding after recurrence had further GBS recurrence. Case fatalities were 3.7%.

CONCLUSIONS

Preterm birth is closely associated with GBS recurrences. Adequately long courses of antibiotics or withdrawal of breast milk may not be useful measures to prevent recurrences.

Epidemiology of Group B Streptococcus: Maternal Colonization and Infant Disease in Kampala, Uganda

Background

Child survival rates have improved globally, but neonatal mortality due to infections, such as group B Streptococcus (GBS), remains a significant concern. The global burden of GBS-related morbidity and mortality is substantial. However, data from low and middle-income countries are lacking. Vaccination during pregnancy could be a feasible strategy to address GBS-related disease burden.

Methods

We assessed maternal rectovaginal GBS colonization and neonatal disease rates in a prospective cohort of 6062 women-infant pairs. Surveillance for invasive infant disease occurred in parallel at 2 Kampala hospital sites. In a nested case-control study, we identified infants <90 days of age with invasive GBS disease (iGBS) (n = 24) and healthy infants born to mothers colonized with GBS (n = 72). We measured serotype-specific anticapsular immunoglobulin G (IgG) in cord blood/infant sera using a validated multiplex Luminex assay.

Results

We found a high incidence of iGBS (1.0 per 1000 live births) within the first 90 days of life across the surveillance sites, associated with a high case fatality rate (18.2%). Maternal GBS colonization prevalence was consistent with other studies in the region (14.7% [95% confidence interval, 13.7%-15.6%]). IgG geometric mean concentrations were lower in cases than controls for serotypes Ia (0.005 vs 0.12 µg/mL; P = .05) and III (0.011 vs 0.036 µg/mL; P = .07) and in an aggregate analysis of all serotypes (0.014 vs 0.05 µg/mL; P = .02).

Conclusions

We found that GBS is an important cause of neonatal and young infant disease in Uganda and confirmed that maternally derived antibodies were lower in early-onset GBS cases than in healthy exposed controls.

Vertical Transmission of Group B Streptococcus, Prevalence, Associated Factors, and Antimicrobial Susceptibility Profile among Newborns Delivered at Health Facilities in Jigjiga City, Ethiopia

Background

Group B Streptococcus (GBS) colonizes the rectovaginal area of women and vertically transmitted to neonates. This bacterium has been linked to severe neonatal complications including pneumonia, septicemia, and meningitis. GBS shows an increased resistance to commonly used antibiotics. Thus, we assessed the vertical transmission, contributing factors, and antimicrobial resistance patterns of GBS among newborns delivered at selected Hospitals in Jigjiga City.

Methods

Hospital-based cross-sectional study was conducted from 1st June 2022 to 30th April 2023. A total of 849 pregnant women admitted to delivery wards from two hospitals were screened for GBS colonization. Subsequently, 162 GBS-colonized pregnant women and their newborn babies were included. A semistructured questionnaire and a review of medical records were used to collect the sociodemographic and clinical characteristics of the study participants. Trained nurses collected swab samples from the vaginal-rectal area of pregnant women and the nasal, ear canal, and umbilical areas of newborn babies. Samples were inoculated on Todd Hewitt broth media supplemented with gentamycin and nalidixic acid and then subcultured on blood agar. Colony characteristics, Gram stain, and catalase test were used for identification. All gram-positive cocci, B-hemolytic, and catalase-negative isolates were further identified using Christie-Atkins-Munch-Petersen and a bacitracin test. The modified Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing. Data were analyzed using SPSS version 26. Logistic regression analysis was used to determine the factors associated with vertical transmission of GBS, and statistical significance was set at p values <0.05.

Result

The overall vertical transmission rate was 41.4% (67/162). History of preterm labor (Adjusted odds ratio (AOR) = 2.25; 95% CI: 1.11, 4.59), history of urinary tract infection (UTI) at current pregnancy (AOR = 2.25; 95% CI: 1.11, 4.59), and prolonged rupture of membranes greater than 18 hours (AOR = 2.23; 95% CI: 1.13, 4.4) were significantly associated with vertical transmission of GBS from previously colonized mothers to their newborn babies. Regarding GBS antibiotic susceptibility profile, a significant degree of resistance was observed to penicillin (29.9%), tetracycline (22.4%), ampicillin (20.9%), and clindamycin (19.4%).

Conclusion

Our study documented a high prevalence of vertical transmission rate of GBS from pregnant women to their babies, with an overall transmission rate of 41.4%. The study identified the presence of antimicrobial-resistant GBS to penicillin, ampicillin, clindamycin, ciprofloxacin, and chloramphenicol. The organism was susceptible to vancomycin, followed by azithromycin, ceftriaxone, and erythromycin. Our study also reported MDR at 13.4%. Based on our findings, there is a need for antenatal culture-based GBS screening, maternal vaccination, and large-scale epidemiological and serotype identification studies to be put into practice in the study area.

Antibody kinetics between birth and three months of life in healthy infants with natural exposure to Group B streptococcus: A UK cohort study

INTRODUCTION

Capsular polysaccharide (CPS) serotype-specific Immunoglobulin G (IgG) in cord blood has been proposed as a correlate of protection against invasive Group B Streptococcus (iGBS) disease. Although protective levels are required in infants throughout the window of vulnerability up to 3 months of age, little is known regarding the kinetics of GBS-specific IgG over this period.

METHODS

We enrolled 33 healthy infants born to mothers colonized with GBS. We collected cord blood and infant blood samples either at one (21-35 days), two (49-63 days), or three months of age (77-91 days). We measured GBS serotype-specific CPS IgG concentrations and calculated the decay rate using a mixed-effects model. We further explored whether the antibody kinetics were affected by common maternal and infant factors and estimated the correlation between IgG concentration at birth and one, two, and three months of age.

RESULTS

The half-life estimate of IgG concentration for homologous and non-homologous GBS serotypes in paired samples with detectable IgG levels at both time points was 27.4 (95 % CI: 23.5-32.9) days. The decay rate did not vary by maternal age (p = 0.7), ethnicity (p = 0.1), gravida (p = 0.1), gestation (p = 0.7), and infant sex (p = 0.1). Predicted IgG titres above the assay lower limit of quantification on day 30 strongly correlated with titres at birth (Spearman correlation coefficient 0.71 [95 % CI: 0.60-0.80]).

CONCLUSION

Our results provide a basis for future investigations into the use of antibody kinetics in defining a serocorrelate of protection against late-onset iGBS disease.

Maternal and neonatal group B streptococcus colonisation: A systematic review and the meta-analysis of matched-pair studies

AIM

To determine the prevalence of group B Streptococcus (GBS) carriage among parturient women and neonates, and the relative risk of vertical transmission, the relative risk of early and late-onset GBS and the pooled incidence of early-late-onset GBS infection.

METHODS

A systematic search of relevant cohort studies from three electronic databases to identify all relevant studies published up to 7 November 2022. The review was conducted in accordance with PRISMA guidelines. Estimates were pooled using random-effects meta-analyses.

RESULTS

A total of 54 articles with 355 787 matched pairs of parturient women and neonates from 30 countries were included in the analysis. The pooled prevalence of GBS colonisation was 17.1% among the pregnant women and 1.0% among neonates. The pooled prevalence of vertical transmission of GBS was 4.5% and the pooled relative risk of GBS colonisation of neonates born to mothers with GBS was 9.9.

CONCLUSION

We support the implementation of targeted intrapartum antibiotic prophylaxis for all women who are positive for GBS as well as women with risks factors for early onset GBS in their infants regardless of their GBS colonisation status.

Vaccine value profile for Group B streptococcus

Group B streptococcus (GBS) is a major global cause of neonatal meningitis, sepsis and pneumonia, with an estimated 91,000 infant deaths per year and an additional 46,000 stillbirths. GBS infection in pregnancy is also associated with adverse maternal outcomes and preterm births. As such, the World Health Organization (WHO) prioritised the development of a GBS vaccine suitable for use in pregnant women and use in LMICs, where the burden of disease is highest. Several GBS vaccines are in clinical development. The WHO Defeating Meningitis by 2030 has set a target of 2026 for vaccine licensure. This 'Vaccine Value Profile' (VVP) for GBS is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations, and in collaboration with stakeholders from the WHO regions of AFR, AMR, EUR, WPR. All contributors have extensive expertise on various elements of the GBS VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Vaginal Carriage of Group B Streptococcus (GBS) in Pregnant Women, Antibiotic Sensitivity and Associated Risk Factors in Dakar, Senegal

The eradication of neonatal Group B Streptococcus (GBS) infections, considered as a major public health priority, necessarily requires a mastery of the data on vaginal carriage in pregnant women. The aims of this study were to determine the prevalence of vaginal carriage of GBS in pregnant women, antibiotic susceptibility, and associated risk factors. This was a cross-sectional, descriptive study conducted over a period of 9 months (July 2020 to March 2021) in pregnant women between 34 and 38 weeks of gestation (WG) followed at the Nabil Choucair health center in Dakar. Identification and antibiotic susceptibility of GBS isolates were performed on the Vitek 2 from vaginal swabs cultured on Granada medium. Demographic and obstetric interview data were collected and analyzed on SPSS (version 25). The level of significance for all statistical tests was set at P < .05. The search of GBS vaginal carriage had involved 279 women aged 16 to 46 years, with a median pregnancy age of 34 (34-37) weeks' gestation. GBS was found in 43 women, for a vaginal carriage rate of 15.4%. In 27.9% (12/43) of volunteers screened, this carriage was monomicrobial, while in 72.1% (31/43) of women, GBS was associated with other pathogens such as Candida spp. (60.5%), Trichomonas vaginalis (2.3%), Gardnerella vaginalis (34.9%) and/or Mobiluncus spp. (11.6%). The level of resistance was 27.9% (12/43) for penicillin G, 53.5% (23/43) for erythromycin, 25.6% (11/43) for clindamycin and 100% for tetracycline. However, the strains had retained fully susceptible to vancomycin and teicoplanin. The main risk factor associated with maternal GBS carriage were ectocervical inflammation associated with contact bleeding (OR = 3.55; P = .005). The high rate of maternal vaginal GBS carriage and the levels of resistance to the various antibiotics tested confirm the importance of continuous GBS surveillance in our resource-limited countries.

Distribution and Prevalence of Serotypes of Group B Streptococcus Isolated from Pregnant Women in 30 Countries: A Systematic Review

Objective

This review aimed to compile scientific data on the distribution and prevalence of group B Streptococcus (GBS) serotypes isolated from pregnant women across 30 countries from 2010 to 2019.

Methods

This was a systematic review that addresses the distribution and prevalence of GBS in pregnant women. The search included studies published between January 2010 and December 2019 in PubMed, Virtual Health Library (BVS), ScienceDirect, Scientific Electronic Library Online (SciELO), and LILACS databases. We also surveyed relevant articles published in English, Spanish, and Portuguese between February and April 2020. Original articles, communication, short report, theses, and dissertations were included. The prevalence of GBS colonization, method for capsular serotyping, antimicrobial resistance, distribution and prevalence of serotypes were extracted from each study.

Results

In all, 795 publications were identified. After applying the eligibility criteria, 48 articles were included for the final systematic analysis; most articles were from Asia and were published during the years 2014 to 2017. For the identification of serotypes, most studies used the polymerase chain reaction technique. There were records of all 10 GBS serotypes, namely, Ia, Ib, and II-IX, among the countries analyzed. GBS susceptibility and resistance to antibiotics were addressed in 37.5% of the publications analysed.

Conclusion

This review showed that GBS serotypes are distributed differently in the 30 analyzed countries, with serotypes Ia, Ib, and II to V being the most prevalent. Furthermore, our results highlighted the relationship of GBS with maternal colonization, implications for neonates, and antibiotic resistance.

Virulence Determinants, Serotypes, and Antimicrobial Resistance of Rectovaginal Isolates of Streptococcus agalactiae

Background & Objective

This study was designed to determine the prevalence of serotypes, virulence-associated genes, and antimicrobial resistance of Streptococcus agalactiae in pregnant volunteers attending a major maternity hospital in Iran.

Methods

The virulence determinants and antimicrobial resistance profiles of 270 Group B streptococcus (GBS) samples were assessed in the adult participants. The prevalence of GBS serotypes, virulence-associated genes, and antimicrobial resistance of the isolates was determined.

Results

The GBS prevalence in the vaginal, rectal, and urinal carrier rates were 8.9%, 4.44%, and 4.44%, respectively, with no concomitant colonization. The serotypes Ia, Ib, and II were at a 1:2:1 ratio. The rectal isolates, harboring CylE, lmb, and bca genes, were of serotype Ia, susceptible to vancomycin. The serotype Ib from urine samples carrying three distinct virulence genes was susceptible to Ampicillin. In comparison, the same serotype with two virulence genes of CylE and lmb exhibited sensitivity to both Ampicillin and Ceftriaxone. The vaginal isolates belonged to serotype II with the CylE gene or serotype Ib with CylE and lmb genes. These isolates harboring the CylE gene were resistant to Cefotaxime. The overall antibiotic susceptibility range was 12.5-56.25%.

Conclusion

The findings broaden our understanding of the pathogenicity of the prevailing GBS colonization and predict different clinical outcomes.

Prevalence of Group B Streptococcus maternal colonization, serotype distribution, and antimicrobial resistance in Sub-Saharan Africa: A systematic review and meta-analysis

OBJECTIVE

Group B Streptococcus (GBS)-associated maternal, perinatal, and neonatal mortality and morbidity disproportionately affects Sub-Saharan Africa (SSA). This systematic review and meta-analysis aimed to address the estimated prevalence, antimicrobial susceptibility, and serotype distribution of GBS isolates in SSA.

METHODS

This study was done according to PRISMA guidelines. MEDLINE/PubMed, CINAHL (EBSCO), Embase, SCOPUS, Web of Sciences databases, and Google Scholar were used to retrieve both published and unpublished articles. STATA software version 17 was used for data analysis. Forest plots using the random-effect model were used to present the findings. Heterogeneity was assessed using Cochrane chi-square (I²) statistics, while the Egger intercept was used to assess publication bias.

RESULTS

Fifty-eight studies that fulfilled the eligibility criteria were included for meta-analysis. The pooled prevalence of maternal rectovaginal colonization and vertical transmission of GBS were 16.06, 95% CI [13.94, 18.30] and 43.31%, 95% CI [30.75, 56.32], respectively. The highest pooled proportion of antibiotic resistance to GBS was observed in gentamicin (45.58%, 95% CI [4.12%, 91.23]), followed by erythromycin, (25.11%, 95% CI [16.70, 34.49]). The lowest antibiotic resistance was observed in vancomycin (3.84%, 95% CI [0.48, 9.22]). Our findings indicate that serotypes Ia/Ib/II/ III/and V cover almost 88.6% of serotypes in SSA.

CONCLUSIONS

The estimated high prevalence and resistance to different antibiotic classes observed in GBS isolates from SSA suggests the need for implementation of effective intervention efforts.

Gastrointestinal, vaginal, nasopharyngeal, and breast milk microbiota profiles and breast milk metabolomic changes in Gambian infants over the first two months of lactation: A prospective cohort study

Microbiota composition in breast milk affects intestinal and respiratory microbiota colonization and the mucosal immune system's development in infants. The metabolomic content of breast milk is thought to interact with the microbiota and may influence developing infant immunity. One hundred seven Gambian mothers and their healthy, vaginally delivered, exclusively breastfed infants were included in our study. We analyzed 32 breast milk samples, 51 maternal rectovaginal swabs and 30 infants' rectal swabs at birth. We also analyzed 9 breast milk samples and 18 infants' nasopharyngeal swabs 60 days post-delivery. We used 16S rRNA gene sequencing to determine the microbiota composition. Metabolomic profiling analysis was performed on colostrum and mature breast milk samples using a multiplatform approach combining 1-H Nuclear Magnetic Resonance Spectroscopy and Gas Chromatography-Mass Spectrometry. Bacterial communities were distinct in composition and diversity across different sample types. Breast milk composition changed over the first 60 days of lactation. α-1,4- and α-1,3-fucosylated human milk oligosaccharides, and other 33 key metabolites in breast milk (monosaccharides, sugar alcohols and fatty acids) increased between birth and day 60 of life. This study's results indicate that infant gut and respiratory microbiota are unique bacterial communities, distinct from maternal gut and breast milk, respectively. Breast milk microbiota composition and metabolomic profile change throughout lactation. These changes may contribute to the infant's immunological, metabolic, and neurological development and could consist the basis for future interventions to correct disrupted early life microbial colonization.

Group B Streptococcus (GBS) colonisation is dynamic over time, whilst GBS capsular polysaccharides-specific antibody remains stable

Group B Streptococcus (GBS) is a leading cause of adverse pregnancy outcomes due to invasive infection. This study investigated longitudinal variation in GBS rectovaginal colonization, serum and vaginal GBS capsular polysaccharide (CPS)-specific antibody levels. Non-pregnant women were recruited in the UK and were sampled every 2 weeks over a 12-week period. GBS isolates were taken from recto-vaginal swabs and serotyped by polymerase chain reaction. Serum and vaginal immunoglobulin G (IgG) and nasal immunoglobulin A (IgA) specific to CPS were measured by Luminex, and total IgG/A by ELISA. Seventy women were enrolled, of median age 26. Out of the 66 participants who completed at least three visits: 14/47 (29.8%) women that were GBS negative at screening became positive in follow-up visits and 16/19 (84.2%) women who were GBS positive at screening became negative. There was 50% probability of becoming negative 36 days after the first positive swab. The rate of detectable GBS carriage fluctuated over time, although serum, vaginal, and nasal CPS-specific antibody levels remained constant. Levels of CPS-specific antibodies were higher in the serum of individuals colonized with GBS than in non-colonized, but similar in the vaginal and nasal mucosa. We found correlations between antibody levels in serum and the vaginal and nasal mucosa. Our study demonstrates the feasibility of elution methods to retrieve vaginal and nasal antibodies, and the optimization of immunoassays to measure GBS-CPS-specific antibodies. The difference between the dynamics of colonization and antibody response is interesting and further investigation is required for vaccine development.

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.

Antimicrobial Resistance Profile and Associated Factors of Group B Streptococci Colonization among Pregnant Women Attending Antenatal Clinics in Jigjiga, Southeast Ethiopia

Background

Streptococcus agalactiae (group B Streptococcus, GBS) is one of the causes of maternal and neonatal morbidity and mortality in many parts of the world. It is associated with severe maternal and neonatal outcomes. The colonization rate, associated factors, and antimicrobial sensitivity (AST) profile of GBS among pregnant women in Eastern Ethiopia is less studied.

Methods

A cross-sectional study was conducted from 1^st  March to 30^th May, 2021 in Jigjiga. A total of 182 pregnant women with a gestational period of ≥36 weeks were included. A structured questionnaire was used to collect data on the participants' demographic and clinical history. Vaginal-rectal samples were collected by brushing the lower vagina and rectum with a sterile cotton swab for bacteriological culture. An antimicrobial sensitivity test (AST) was performed using the Kary-Bauer disk diffusion method. Data were entered and analyzed using SPSS version 25. The logistic regression model was used to find out factors associated with GBS colonization.

Results

GBS colonization among pregnant women attending antenatal care was at 15.9% (29/182). The AST result showed that the majority of the isolates were sensitive to vancomycin (96.6%), chloramphenicol (96.6%), ampicillin (93.1%) azithromycin (89.7%), and penicillin (86.2%). In contrast, the isolates were found to be resistant to ceftriaxone, erythromycin, ciprofloxacin, clindamycin, and tetracycline at 17.2%, 20.7%, 27.6%, 27.6%, and 34.5%, respectively. Multidrug resistance (MDR) was noted in 4 isolates (13.79%). GBS colonization was significantly associated a with history of preterm labor (<37 weeks of gestation) (AOR = 3.87, 95% CI = 1.36–10.9) and a history of prolonged ruptured membrane (>18 hr.) (AOR = 3.44, 95% CI = 1.34–8.83).

Conclusions

The colonization rate of GBS was considerably high among pregnant women attending antenatal care in the present study area. The observed antimicrobial resistance for the common drugs and the reported MDR level calls for routine screening of pregnant women for GBS and actions to minimize antimicrobial resistance (AMR) should be strengthened.

Group B Streptococci Vaginal-Recto Colonization, Vertical Transmission to Newborns, Antimicrobial Susceptibility Profile and Associated Factors in Selected Health Facilities of Bahir Dar City: A Cross-Sectional Study

BACKGROUND

Group B streptococci (GBS) is an important pathogen involved in stillbirths, neonatal deaths and neurological defects, and the occurrence of multi-drug resistance (MDR) is an alarming issue. This study determined the prevalence of GBS colonization in pregnant women and newborns, the proportion of vertical transmission, antimicrobial susceptibility profiles of isolates, and the factors associated with colonization and vertical transmission.

METHODS

A cross-sectional study was conducted from March 1, 2021 to June 30, 2021, at selected health facilities of Bahir Dar city. Vaginal-recto swabs from 292 pregnant women and pooled ear, nasal and umbilical swabs from 292 newborns were collected. GBS were identified following standard microbiological protocols. Antimicrobial susceptibility testing was performed using modified Kirby-Bauer disk diffusion method and interpreted by the accepted 2020 CLSI M100 guidelines. Logistic regression analysis was computed.

RESULTS

Overall, 54 (18.5%) of pregnant women and 22 (7.5%) of newborns had GBS colonization. The proportion of GBS vertical transmission was 22 (40.7%). Group B Streptococcus isolates scored susceptibility to penicillin, ampicillin and vancomycin with 88.9%, 90.7%, and 96.3% for pregnant women and 86.4%, 90.9% and 95.9% for newborns, respectively. A high percentage of non-susceptibility was found for clindamycin and erythromycin with 33.3% and 25.9% for pregnant women and 31.8% and 22.7% from newborns, respectively. Besides, 19 (35.2%) GBS from pregnant women and 8 (36.4%) from newborns were MDR. Group B streptococci colonization was significantly associated with delivery before 37th week of gestation (AOR=2.77, 95% CI 1.14-6.68) and history of stillbirth (AOR=3.13, 95% CI 1.13-8.70).

CONCLUSION

Pregnant women vaginal-recto GBS colonization and transmission to newborns connected with MDR are a matter of concerns. Although non-susceptible GBS isolates are obtained, penicillin and vancomycin are relatively effective. The use of clindamycin, erythromycin and ceftriaxone should be guided by antimicrobial susceptibility testing. Genetic analysis is recommended to exactly identify the epidemiology of GBS strains, vertical transmission and antimicrobial resistance at the country level.

Group B Streptococcal Colonization in African Countries: Prevalence, Capsular Serotypes, and Molecular Sequence Types

Streptococcus agalactiae or group B streptococcus (GBS) is a commensal of the gastrointestinal and genitourinary tracts of healthy women and an important cause of neonatal invasive infections worldwide. Transmission of bacteria to the newborn occurs at birth and can be prevented by intrapartum antibiotic prophylaxis. However, this not available in resource limited settings in Africa, which carries a particular high burden of disease. Serotype based vaccines are in development and present a suitable alternative to prevent neonatal infections. To be able to assess vaccine efficacy, knowledge and surveillance of GBS epidemiological data are required. This review summarizes investigations about the serotype distribution and the multi-locus sequence types (MLST) found in different African countries. While most serotypes and MLST data are comparable to findings from other continents, some specific differences exist. Serotype V is predominant among colonizing maternal strains in many different African countries. Serotypes that are rarely detected in western industrialized nations, such as serotypes VI, VII and IX, are prevalent in studies from Ghana and Egypt. Moreover, some specific MLST sequence types that seem to be more or less unique to Africa have been detected. However, overall, the data confirm that a hexavalent vaccine can provide broad coverage for the African continent and that a protein vaccine could represent a promising alternative.

Group B Streptococcus colonisation, prevalence, associated risk factors and antimicrobial susceptibility pattern among pregnant women attending antenatal care at Dschang District Hospital, West Region of Cameroon: A hospital-based cross-sectional study

BACKGROUND

Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a Gram-positive bacterium known for its ability to colonise the vaginal and rectal areas of the mother and is a leading cause of neonatal mortality and morbidity. This study aimed at determining the prevalence, associated risk factors and antimicrobial susceptibility of GBS colonisation among pregnant women attending antenatal care (ANC) at Dschang District Hospital.

METHODS

This hospital-based cross-sectional study used a multistage sampling method to recruit a total of 621 consented pregnant women who attended ANC in Dchang District Hospital. The 621 Participants at 23.5 ± 6.4 weeks gestation each completed a questionnaire and vaginal swabs were collected for GBS analysis.

RESULTS

Among the 621 pregnant women that were included in this study, the colonisation rate of GBS was found to be 8.69%. Induced abortion (odds ratio [CI] = 3.09, 95% [1.56-6.21]), Spontaneous abortions (OR = 2.82, 95% CI 1.14-7.29), Stillbirth (OR [CI] = 7.75, 95% [2.61-21.71]), Fever (OR [CI] = 0.37, 95% [0.19-0.71]) and anaemia (OR [CI] = 0.22, 95% [0.12-0.43]) were found to be factors associated with GBS colonisation.

CONCLUSION

Our findings suggest that we found that, induce abortion, spontaneous abortions and stillbirths were highly associated rates of GBS colonisation, while fever and anaemia were associated with lower rates of GBS colonisation. Further longitudinal research is needed to establish the causal relationship and its biological mechanisms.

Group B streptococcus neonatal umbilical colonization managed by dry cord care in nurseries: A retrospective cohort study

BACKGROUND

Screening-based intrapartum antibiotic prophylaxis (IAP) has reduced the prevalence of early-onset group B Streptococcus (GBS) infection in newborns. Nevertheless, early-onset disease still occurs despite IAP, and IAP is not effective in preventing late-onset disease. This study aimed to determine the prevalence and risk factors of GBS neonatal umbilical colonization managed by dry cord care in Japan.

METHODS

Of 735 healthy newborns in the well-baby nursery at Saitama City Hospital, 353 from whom umbilical bacterial swabs were obtained before discharge were included in the analysis. Maternal and neonatal clinical characteristics were retrospectively reviewed.

RESULTS

GBS was detected in 4.2% (15/353) of umbilical swabs; 13/15 (86.8%) were born to GBS-negative mothers. The median (IQR) age at umbilical swab collection was 4.0 (4.0-5.0) days. Comparison of clinical characteristics between GBS-positive and negative neonates revealed a significant difference in the proportion of vaginal deliveries (15/15 [100%] in GBS-positive neonates vs. 115/338 [34.0%] in GBS-negative neonates, p < 0.0001). Of 15 GBS-positive neonates, 10 (66.7%) were also co-colonized with other enteric bacteria such as Escherichia coli.

CONCLUSION

Vaginal delivery was a risk factor associated with GBS neonatal umbilical colonization in Japanese neonates. Co-colonization with multiple enteric bacterial species implicates vertical transmission of GBS from undetected carrier mothers during passage through the birth canal.

Prevalence, Resistance Profile and Virulence Genes of Streptococcus agalactiae Colonizing Near-term Pregnant Women Attending Ain Shams University Hospital

Group B streptococcus (GBS) is a common cause of infections in pregnant females and non-pregnant adults with chronic diseases (such as diabetes and cancer), also it is the main reason of septicaemia and meningitis in infants. The aim of this study was to figure out how common GBS is in pregnant women, the antimicrobial sensitivity pattern of the isolated GBS colonies and check the presence of scpB and rib virulence genes in these isolates. We screened 203 pregnant women attending the Maternity Hospital of Ain Shams University using vaginal sampling. Isolation was done on CHROMagarTM Strep B and sheep blood agar plates then identified via colony characters, Gram stain, test for catalase production, Christie–Atkins–Munch-Petersen (CAMP) test, test for hippurate hydrolysis and latex agglutination test. This was followed by an antibiotic susceptibility test. Finally, Detection of scpB and rib virulence genes by conventional PCR was done. Our study detected that the prevalence rate of GBS in involved pregnant women was 11.33%. A statistically significant association between colonization and history of spontaneous abortion and preterm labor was observed. CHROMagar™ StrepB showed the same sensitivity of sheep blood agar with extensive effort to isolate suspected GBS colonies from blood agar. GBS was 100% sensitive to levofloxacin, linezolid, cefepime, ceftaroline and ceftriaxone. Also, it was highly sensitive to vancomycin (91.3%). Sensitivity to clindamycin, azithromycin, penicillin and ampicillin was (21.70%, 21.70%,47.80%, 47.80%) respectively. The least sensitivity of GBS was to erythromycin ( 8.7%). All isolates possessed the scpB gene (100%) while only 18 isolates (78.26%) had the rib gene.

Prevalence, serotype and antibiotic susceptibility of Group B Streptococcus isolated from pregnant women in Jakarta, Indonesia

Group B Streptococcus (GBS) is a bacterial pathogen which is a leading cause of neonatal infection. Currently, there are limited GBS data available from the Indonesian population. In this study, GBS colonization, serotype distribution and antimicrobial susceptibility profile of isolates were investigated among pregnant women in Jakarta, Indonesia. Demographics data, clinical characteristics and vaginal swabs were collected from 177 pregnant women (mean aged: 28.7 years old) at 29–40 weeks of gestation. Bacterial culture identification tests and latex agglutination were performed for GBS. Serotyping was done by conventional multiplex PCR and antibiotic susceptibility testing by broth microdilution. GBS colonization was found in 53 (30%) pregnant women. Serotype II was the most common serotype (30%) followed by serotype III (23%), Ia and IV (13% each), VI (8%), Ib and V (6% each), and one non-typeable strain. All isolates were susceptible to vancomycin, penicillin, ampicillin, cefotaxime, daptomycin and linezolid. The majority of GBS were resistant to tetracycline (89%) followed by clindamycin (21%), erythromycin (19%), and levofloxacin (6%). The serotype III was more resistant to erythromycin, clindamycin, and levofloxacin and these isolates were more likely to be multidrug resistant (6 out of 10) compared to other serotypes. This report provides demographics of GBS colonization and isolate characterization in pregnant women in Indonesia. The results may facilitate preventive strategies to reduce neonatal GBS infection and improve its treatment.

Prevalence, antimicrobial susceptibility patterns, serotypes and risk factors for group B streptococcus rectovaginal isolates among pregnant women at Kenyatta National Hospital, Kenya; a cross-sectional study

BACKGROUND

Estimates of Group B Streptococcus (GBS) disease burden, antimicrobial susceptibility, and serotypes in pregnant women are limited for many resource-limited countries including Kenya. These data are required to inform recommendations for prophylaxis and treatment of infections due to GBS.

METHODS

We evaluated the prevalence, antimicrobial susceptibility patterns, serotypes, and risk factors associated with rectovaginal GBS colonization among pregnant women receiving antenatal care at Kenyatta National Hospital (KNH) between August and November 2017. Consenting pregnant women between 12 and 40 weeks of gestation were enrolled. Interview-administered questionnaires were used to assess risk factors associated with GBS colonization. An anorectal swab and a lower vaginal swab were collected and cultured on Granada agar for GBS isolation. Positive colonies were tested for antimicrobial susceptibility to penicillin G, ampicillin, vancomycin, and clindamycin using the disk diffusion method. Serotyping was performed by latex agglutination. Logistic regression was used to identify factors associated with GBS colonization.

RESULTS

A total of 292 women were enrolled. Median age was 30 years (Interquartile range {IQR} 26-35) and a median gestational age of 35 weeks (IQR 30-37). Overall GBS was identified in 60/292 (20.5%) of participants. Among the positive isolates, resistance was detected for penicillin G in 42/58 (72.4%) isolates, ampicillin in 32/58 (55.2%) isolates, clindamycin in 14/46 (30.4%) isolates, and vancomycin in 14/58 (24.1%) isolates. All ten GBS serotypes were isolated, and 37/53 (69.8%) of GBS positive participants were colonized by more than one serotype. None of the risk factors was associated with GBS colonization.

CONCLUSION

The prevalence of GBS colonization was high among antenatal women at KNH. In addition, a high proportion of GBS isolates were resistant to commonly prescribed intrapartum antibiotics. Hence, other measures like GBS vaccination is a potentially useful approaches to GBS prevention and control in this population. Screening of pregnant mothers for GBS colonization should be introduced and antimicrobial susceptibility test performed on GBS positive samples to guide antibiotic prophylaxis.

Proportion of Streptococcus agalactiae vertical transmission and associated risk factors among Ethiopian mother-newborn dyads, Northwest Ethiopia

Group B Streptococcus (GBS) vertical transmission causes fetal and neonatal colonization and diseases. However, there is scarcity of data in low-income countries including Ethiopia. We conducted a cross-sectional study on 98 GBS positive mothers, and their newborns to find proportion of vertical transmission. GBS was identified from swabs by using recommended methods and vertical transmission at birth was confirmed by the culture of body surface swabs of newborns within 30 minutes following birth. GBS positivity among swabbed specimens collected for other purposes was 160/1540 (10.4%); 98 were from 385 recto-vaginal swabs of pregnant women, and 62 were from 1,155 swabs of the 385 births. Of the 98 GBS positive cases, 62 newborns were GBS colonized with vertical transmission proportion of 63.3%(95% CI: 54.1–72.4%). We identified that the proportion of vertical transmission in this study was within the range of other many global studies, but higher than recently published data in Ethiopia. Maternal educational level, employment and lower ANC visit were significantly associated risk factors to GBS vertical transmission. Efforts need to be made to screen pregnant women during antenatal care and to provide IAP to GBS positive cases to reduce mother to newborn vertical transmission.

WHO consultation on group B Streptococcus vaccine development: Report from a meeting held on 27-28 April 2016

Globally, group B Streptococcus (GBS) remains a leading cause of sepsis and meningitis in infants in the first 90days of life. Intrapartum antibiotic prophylaxis (IAP) for women at increased risk of transmitting GBS to their newborns has been effective in reducing part, but not all, of the GBS disease burden in many high income countries (HICs). In low- and middle-income countries (LMICs), IAP use is low. Immunization of pregnant women with a GBS vaccine represents an alternative strategy to protecting newborns and young infants, through transplacental antibody transfer and potentially by reducing new vaginal colonization. This vaccination strategy was first suggested in the 1970s and several potential GBS vaccines have completed phase I/II clinical trials. During the 2015 WHO Product Development for Vaccines Advisory Committee meeting, GBS was identified as a high priority for the development of a vaccine for maternal immunization because of the major public health burden posed by GBS in LMICs, and the high technical feasibility for successful development. Following this meeting, the first WHO technical consultation on GBS vaccines was held on the 27th and 28th of April 2016, to consider development pathways for such vaccines, focused on their potential role in reducing newborn and young infant deaths and possibly stillbirths in LMICs. Discussion topics included: (1) pathophysiology of disease; (2) current gaps in the knowledge of global disease burden and serotype distribution; (3) vaccine candidates under development; (4) design considerations for phase III trials; and (5) pathways to licensure, policy recommendations and use. Efforts to address gaps identified in each of these areas are needed to establish the public health need for, the development and deployment of, efficacious GBS vaccines. In particular, more work is required to understand the global disease burden of GBS-associated stillbirths, and to develop quality-assured standardized antibody assays to identify correlates of protection.

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.

Group B streptococcus colonisation and associated risk factors among pregnant women: A hospital-based study and implications for primary care

BACKGROUND

Group B streptococcus (GBS), which asymptomatically colonises the vaginal and rectal areas of women, is a leading cause of neonatal mortality and morbidity. This study aimed to determine the prevalence and factors associated with GBS colonisation among pregnant women in Shenzhen, China.

METHODS

A hospital-based cross-sectional survey was conducted, using a multistage sampling method. Pregnant women at ≥28 weeks' gestation completed a questionnaire and vaginal swabs were obtained for GBS analysis. Data were analysed by chi-squared tests and logistic regression models.

RESULTS

The colonisation rate of GBS among pregnant women was 4.9%. The influencing factors associated with GBS colonisation included body mass index before pregnancy (odds ratio [OR] = 3.79, 95% CI 1.28-11.26), gestational age (OR = 5.81, 95% CI 1.20-28.15), induced abortion (OR = 0.63, 95% CI 0.40-0.98) and lotion use before pregnancy (OR = 1.59, 95% CI 1.04-2.44).

CONCLUSIONS

Our findings suggest that obesity, gestational age, induced abortion and lotion use were significantly associated with GBS colonisation. Further longitudinal research is needed to establish the causal relationship and its biological mechanisms.

Outcome of a screening program for the prevention of neonatal early-onset group B Streptococcus infection: a population-based cohort study in Inner Mongolia, China

PURPOSE

Invasive early-onset group B Streptococcus infection (EOGBS) is an important cause of severe neonatal complications but study on comprehensive GBS screening is lacking in China. This study aims to investigate the outcome of a regional anterpartum screening program for EOGBS prevention and to estimate the pros and cons of a new GBS screening strategy employed.

METHODS

We performed an optimized hospital strategy for GBS screening, which targeted expectant mothers (including those with preterm births) from January 2016 to December 2016 in a population-based cohort. Three common screening strategies were simulated to estimate the availability of the hospital strategy used in this study.

RESULTS

Altogether, 9770 eligible women were tested and the rate of GBS carriage was 2.7  % (266/9770). In total, 198 of the 266 maternal GBS carriers accepted intrapartum antibiotic prophylaxis (IAP) treatment. Among the 9860 neonates of 9770 mothers, four cases of EOGBS infection were identified and one case was missed (EOGBS incidence with screening and IAP: 0.5/1000). Risk factors for maternal GBS colonization included preterm birth (between 35 and 37 weeks) [odds ratio (OR)=1.7 (95  % confidence interval: 1.22-2.33)], region of origin, resident areas, maternal age (older than 34 years) [OR=1.5 (1.06-2.09)], prelabour rupture of membranes [OR=1.8 (1.34-2.35)], gestational diabetes mellitus [OR=1.6 (1.14-2.28)] and maternal mild anemia (Hb: 90-110 g dl^-1) [OR=1.5 (1.16-2.06)]. This new screening strategy resulted in less antibiotic exposure and least number of cases missed.

CONCLUSIONS

Our findings illustrate that this perinatal screening (including preterm births) for prevention of EOGBS infection can be implemented in the Inner Mongolian area.

Risk Factors for Infant Colonization by Hypervirulent CC17 Group B Streptococcus: Toward the Understanding of Late-onset Disease

The hypervirulent group B Streptococcus clone CC17 accounts for the majority of infant late-onset disease (LOD). We provide evidence that the high incidence of CC17 in LOD is likely due to an enhanced post-delivery mother-to-infant transmission.

Streptococcus agalactiae maternal colonization, antibiotic resistance and serotype profiles in Africa: a meta-analysis

Background

Maternal rectovaginal colonization with Streptococcus agalactiae (Group B Streptococcus or GBS) is the most common route for the GBS disease in the perinatal period. The knowledge of maternal colonization, antibiotic resistance and serotype profiles is substantially needed to formulate the broad vaccine. However, it has not been estimated in Africa. This meta-analysis was aimed to determine the pooled prevalence of colonization, antibiotic resistance and serotype profiles of GBS reported in Africa.

Methods

Potentially relevant studies from 1989 to 31th January, 2019 were retrieved from the Medline/PubMed, EMBASE, HINARI online databases, periodicals and by requesting authors. Unpublished studies retrieved from grey literature through Google and Google Scholar. Pooled estimates were calculated using the random effect model. Subgroup analysis was done to investigate the burden of colonization across sub-regions, sampling site and countries. Summary estimates were presented using words, Forest plots and Tables. Heterogeneity was assessed using the I² statistic.

Results

Eighty-three articles were assessed, of which 57 studies conducted in five sub-regions with 21 countries (22,206 pregnant women) met pre-specified inclusion criteria. The overall estimate of recto-vaginal colonization was 19.3% (95% CI 16.9, 21.7). The highest estimate was observed in Southern Africa, 23.8% (95% CI 18.7, 28.9), followed by Northern Africa, 22.7% (95% CI 18.2, 27.2) while the lowest was driven from the Eastern Africa, 15.4% (95% CI 12.1, 18.7). Considerable heterogeneity across and within regions, sampling site, screening methods and countries (I² > 75%); and the publication bias were observed (p = 0.031). GBS showed the highest resistance to tetracycline. Resistance to penicillin, amoxicillin, chloramphenicol, ampicillin, ceftriaxone, ciprofloxacin, erythromycin, vancomycin and clindamycin also observed. The V, III, Ia, Ib, and II serotypes altogether were accounted 91.8% in the African studies.

Conclusions

The pooled estimate of the maternal colonization with GBS was 19.3% which is equivalent with other many primary and review reports worldwide. The most antibiotic resistance estimate was recorded in the tetracycline followed by penicillin. Five serotypes were the most prevalent in Africa and more data on the antibiotic résistance and serotype distribution patterns are needed from developing countries to devise the effective preventive measures. In addition, the antibiotic susceptibility test methods used in the Africa shall be assessed for its quality.

Trial registration Prospero Registration Number CRD42018094525

Surface Structures of Group B Streptococcus Important in Human Immunity

The surface of the Gram-positive opportunistic pathogen Streptococcus agalactiae, or group B Streptococcus (GBS), harbors several carbohydrate and protein antigens with the potential to be effective vaccines. Capsular polysaccharides of all clinically-relevant GBS serotypes coupled to immunogenic proteins of both GBS and non-GBS origin have undergone extensive testing in animals that led to advanced clinical trials in healthy adult women. In addition, GBS proteins either alone or in combination have been tested in animals; a fusion protein construct has recently advanced to human clinical studies. Given our current understanding of the antigenicity and immunogenicity of the wide array of GBS surface antigens, formulations now exist for the generation of viable vaccines against diseases caused by GBS.

Prevalence and capsular type distribution of Streptococcus agalactiae isolated from pregnant women in Namibia and South Africa

Background

Streptococcus agalactiae or Group B Streptococcus (GBS) is the leading cause of neonatal morbidity and mortality resulting in septicaemia, bacteraemia and meningitis. Long term problems in children range from loss of hearing to mental retardation. While Intrapartum Antibiotic Prophylaxis (IAP) has reduced the incidence of S. agalactiae infection, it still remains the leading cause of disease in neonates. GBS has ten capsular types whose distribution varies across the world. Therefore, this study sought to determine the prevalence of GBS in Namibia and South Africa amongst pregnant women between 35 and 37 weeks gestation and elucidate the capsular types.

Methods

Lower vaginal and rectal swabs were collected from pregnant women between 35 and 37 weeks gestation. Five hundred and thirty pregnant women were recruited into the study in Windhoek, Namibia while one hundred pregnant women were recruited in the Eastern Cape, South Africa. The swabs were cultured on 5% sheep blood agar (Biomerieux, New Jersey, USA) for isolation of GBS. Presumptive isolates were confirmed using both the Vitek (2) and molecular techniques targeting the scpB gene. Capsular typing was performed in a multiplex PCR with capsular specific primer pairs.

Results

The prevalence of GBS in Namibia was 13.6 and 37% in South Africa respectively. In both countries most women were dually colonised with GBS. Capsular types II, III and V were the most prevalent.

Conclusions

The prevalence of GBS in Namibia was lower than in South Africa in this study. The prevalence in both countries was not different from those reported in other African countries and around the world. The predominant capsular types in this study are the ones commonly associated with adverse maternal outcomes.

Evaluation of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the Identification of Group B Streptococcus

Objective

Group B Streptococcus (GBS) is a leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotics given to women carrying GBS are an effective means of reducing disease in the first week of life. Rapid and reliable tests are needed to accurately identify GBS from these women for timely intrapartum antibiotic administration to prevent neonatal disease. Many laboratories now use matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) by direct plating or cell lysis for the identification of GBS isolates. The cell lysis step increases time to results for clinical samples and is more complex to perform. Therefore, we seek to evaluate the sensitivity and specificity of the quicker and more rapid direct plating method in identifying GBS.

Results

We directly compared swab isolates analysed by both direct plating and cell lysis method and demonstrated that direct plating has a sensitivity and specificity of 0.97 and 1, respectively, compared to an additional cell lysis step. We demonstrated that MALDI-TOF MS can be successfully used for batch processing by the direct plating method which saves time. These results are reassuring for laboratories worldwide who seek to identify GBS from swabs samples as quickly as possible.

Streptococcus agalactiae from Ethiopian pregnant women; prevalence, associated factors and antimicrobial resistance: alarming for prophylaxis

Background

Maternal Streptococcus agalactiae (Group B Streptococcus, GBS) colonization rates and its antibiotic resistance patterns provide important information useful in guiding prevention strategies. There is a paucity of evidence about GBS in the Amhara National Regional State, Ethiopia.

Objective

To determine colonization prevalence, associated risk factors, and antibiotics resistance including inducible clindamycin resistance patterns of GBS among Ethiopian pregnant women.

Methods

A prospective cross-sectional study was conducted from 1st December 2016 to 30th November 2017 at the University of Gondar Referral hospital delivery ward. Combined recto-vaginal swabs were collected from 385 pregnant women and analyzed at the University of Gondar Bacteriology Laboratory by using LIM broth and 5% defibrinated sheep blood agar culture methods. Isolates were identified by using colony morphology, gram reaction, hemolysis, and CAMP test. Antibiotic susceptibility test was done using the disc diffusion method. Double disc diffusion method was used to identify inducible clindamycin resistance isolates. Data were analyzed by SPSS version 20 software. p ≤ 0.05 was considered as statistically significant.

Results

The overall prevalence of maternal GBS colonization was 25.5% (95% CI 21–29.5%). Experiencing meconium stained amniotic fluid (AOR = 3.018, 95% CI 1.225, 7.437), and longer duration of premature rupture of membrane (AOR = 1.897, 95% CI 1.014, 3.417) were statistically significant to maternal colonization. Furthermore, GBS resistant to 0 (8.2%), 1 (25.5%) and 3 (39.8%) or more antibiotics were identified. A D-test showed 15.2% inducible clindamycin resistant GBS. Constitutive macrolide lincosamide–streptogramin_B, L-, and M-phenotypes were also detected.

Conclusions

Maternal GBS colonization rate in this study was higher compared to the previous reports in Ethiopia. This much prevalence and antibiotics resistance results are the clue to which attention shall be given to this bacterium during management of pregnant women and the newborns.

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.

Serial Clustering of Late-Onset Group B Streptococcal Infections in the Neonatal Unit: A Genomic Re-evaluation of Causality

Background

Invasive Group B streptococcus (GBS) is a major cause of serious neonatal infection. Current strategies to reduce early-onset GBS disease have no impact on late-onset disease (LOD). Although GBS LOD is viewed as a sporadic event in the community, LOD arising within the neonatal intensive care unit (ICU) raises questions about mode of acquisition.

Methods

Following a cluster of 4 GBS LOD cases, enhanced surveillance for all GBS LOD was undertaken over 2 years in the neonatal ICU supported by neonatal rectal screening. GBS isolates were serotyped and genome-sequenced.

Results

Twelve late -onset invasive GBS episodes were identified (incidence 0.6/1000 live births). Genomic analysis revealed that 11/12 GBS isolates (92%) were linked to at least one other LOD isolate. Isolates from the first cluster were serotype V, resistant to macrolides and lincosamides, and sequencing confirmed isolates were indistinguishable, or distinguishable by only one SNP difference, from each other. Rectal carriage was rare. Prospective surveillance identified three further clusters of LOD due to serotypes Ia (3 cases), Ib (2 cases), and III (2 cases), that would not have been identified without surveillance and genome sequencing, leading to a re-evaluation of interventions required to prevent GBS LOD.

Conclusion

Acquisition routes for LOD GBS in the neonatal ICU are poorly understood; cases may not necessarily be sporadic. Within this neonatal ICU, our data suggest that a single case of LOD GBS sepsis should be considered a potential nosocomial transmission event warranting prompt investigation, heightened infection prevention vigilance and action where required.

Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay

BACKGROUND

Streptococcus Group B (GBS) colonization in pregnant women is the most important risk factor for newborn disease due to vertical transmission during delivery. GBS colonization during pregnancy has been implicated as a leading cause of perinatal infections. Traditionally, pregnant women are screened for GBS between 35 and 37 weeks of gestation. However, antenatal culture-based screening yields no information on GBS colonization status and offers low predictive value for GBS colonization at delivery. Numerous assays have been evaluated for GBS screening in an attempt to validate a fast and efficient method. The aim of this study was to compare bacteria isolation by culture and two qPCR techniques, targeting sip and cfb genes, respectively, for detecting colonizing GBS.

METHODS

Cultures - the gold-standard technique, a previous qPCR technique targeting the sip gene, and a new proposed qPCR assay targeting the cfb gene were evaluated as diagnostic tools on 320 samples.

RESULTS

Considering cultures as the gold standard, the evaluated qPCR method detected 75 out of 78 samples, representing a sensitivity of 93.58% (95% confidence interval (CI), 90.89-96.27) and specificity of 94.62% (95% CI, 91.78-97.46). However, an additional analysis was performed for true positives that included not only samples showing positives by culture but samples showing positive for both qPCR assays. The sensitivity and specificity were recalculated including these discrepant samples and a total of 89 samples were considered as positive, giving a prevalence of 27.81%. With this new analysis, the qPCR targeting the cfb gene showed a sensitivity of 95.5% (95% CI, 88.65-98.59) and specificity of 99.13% (95% CI, 96.69-99.97).

CONCLUSIONS

The new qPCR method is a sensitive and specific assay for detecting GBS colonization and represents a valuable tool for identifying candidates for intrapartum antibiotic prophylaxis. Cultures should be retained as the reference and the routine technique because of its specificity and cost analysis ratio, but it would be convenient to introduce PCR techniques to check negative culture samples or when an urgent detection is required to reduce risk of infection among infants.

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.

Infant Group B Streptococcal Disease Incidence and Serotypes Worldwide: Systematic Review and Meta-analyses

Background

Group B Streptococcus (GBS) remains a leading cause of neonatal sepsis in high-income contexts, despite declines due to intrapartum antibiotic prophylaxis (IAP). Recent evidence suggests higher incidence in Africa, where IAP is rare. We investigated the global incidence of infant invasive GBS disease and the associated serotypes, updating previous estimates.

Methods

We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus) and sought unpublished data regarding invasive GBS disease in infants aged 0–89 days. We conducted random-effects meta-analyses of incidence, case fatality risk (CFR), and serotype prevalence.

Results

We identified 135 studies with data on incidence (n = 90), CFR (n = 64), or serotype (n = 45). The pooled incidence of invasive GBS disease in infants was 0.49 per 1000 live births (95% confidence interval [CI], .43–.56), and was highest in Africa (1.12) and lowest in Asia (0.30). Early-onset disease incidence was 0.41 (95% CI, .36–.47); late-onset disease incidence was 0.26 (95% CI, .21–.30). CFR was 8.4% (95% CI, 6.6%–10.2%). Serotype III (61.5%) dominated, with 97% of cases caused by serotypes Ia, Ib, II, III, and V.

Conclusions

The incidence of infant GBS disease remains high in some regions, particularly Africa. We likely underestimated incidence in some contexts, due to limitations in case ascertainment and specimen collection and processing. Burden in Asia requires further investigation.

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.

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.

Neonatal colonization of group B Streptococcus in China: Prevalence, antimicrobial resistance, serotypes, and molecular characterization

BACKGROUND

Group B Streptococcus (GBS) remains a leading cause of neonatal mortality and morbidity. This study aimed to determine the prevalence, antimicrobial susceptibility, serotypes, and molecular characterization of GBS colonized in neonates.

METHODS

A cross-sectional study was conducted using a multistage sampling method. Swabs for GBS identification were taken from infants' ear, oral cavity, and umbilicus immediately after birth. All GBS isolates were tested for antimicrobial susceptibility, resistance genes, serotyping, multilocus sequence typing, and virulence genes.

RESULTS

Of the 1,814 neonates, 1.3% tested positive for GBS, with 66.7% tested as multidrug resistant. All GBS isolates were susceptible to penicillin, but rates of resistance to tetracycline and erythromycin were high (70.8%), with the predominant resistance genes being tetM and ermB. The predominant serotype was III, followed by Ia and Ib, and the most common genotypes were sequence type (ST) 19, ST10, and ST485. Notably, we found that ST19 and ST17 isolates were associated with serotype III, resistant to tetracycline, erythromycin, and clindamycin, and carrying ermB, tetM, and rib; ST10 and ST12 isolates were associated with serotype Ib, resistant to erythromycin and clindamycin, and carrying ermB and alphaC; and ST485 isolates were associated with serotype Ia and carrying mefA/E, tetM, and epsilon.

CONCLUSIONS

These findings indicate a high prevalence of multidrug-resistant GBS and specific phenotype-genotype combinations for GBS clones.

Breast Milk Cytokines and Early Growth in Gambian Infants

Background: Breast milk provides nutrition for infants but also delivers other bioactive factors that have key protective and developmental benefits. In particular, cytokines are thought to play a role in immunomodulation, although little is known about their impact on health outcomes in early life. Objective: The purpose of this pilot study was to evaluate the relationship between cytokines in breast milk and infant growth outcomes in a low-income setting. Methods: 100 mother-infant pairs were followed up to 2-3 months postpartum as part of a prospective longitudinal cohort study in urban Gambia, West Africa. The concentrations of 9 pro-inflammatory cytokines (IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL-13, IFN-γ, TNFα), IGF-1 and TGFβ2 were measured in colostrum within 12 h of birth and in breast milk at the final visit, scheduled between day 60 and 89 postpartum. Infant weight was recorded and converted to weight-for-age Z-scores (WAZ) at the same time points. Growth outcomes were defined in our study as (a) change in WAZ between birth and final visit (b) WAZ at final visit. Linear regression analysis was used to determine the ability of colostrum and breast milk cytokine concentrations to predict growth outcomes up to 2-3 months postpartum. Results: Gambian infants demonstrated growth faltering across the first 2-3 months postpartum. There was no significant relationship between cytokines in colostrum and subsequent change in WAZ between birth and the final visit, in either unadjusted or adjusted models. However, cytokines in mature breast milk, TNFα, IFNγ, IL1β, IL2, IL4, and IL6, were weak negative predictors of WAZ scores at the final visit, in unadjusted models (p < 0.05). When adjusted for maternal anemia (as a proxy for maternal nutrition), TNFα and IL6 remained significant predictors (p < 0.05). Conclusions: Variations in breast milk cytokine levels do not play a substantial role in the growth faltering observed across early infancy. The potential contribution of other factors, such as micronutrients, hormones or human milk oligosaccharides, must be elucidated. Cytokine levels in mature breast milk were weakly predictive of poor infant growth, possibly reflecting a "read-out" of suboptimal maternal health and nutrition.

Maternal Colonization With Group B Streptococcus and Serotype Distribution Worldwide: Systematic Review and Meta-analyses

BACKGROUND

Maternal rectovaginal colonization with group B Streptococcus (GBS) is the most common pathway for GBS disease in mother, fetus, and newborn. This article, the second in a series estimating the burden of GBS, aims to determine the prevalence and serotype distribution of GBS colonizing pregnant women worldwide.

METHODS

We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus), organized Chinese language searches, and sought unpublished data from investigator groups. We applied broad inclusion criteria to maximize data inputs, particularly from low- and middle-income contexts, and then applied new meta-analyses to adjust for studies with less-sensitive sampling and laboratory techniques. We undertook meta-analyses to derive pooled estimates of maternal GBS colonization prevalence at national and regional levels.

RESULTS

The dataset regarding colonization included 390 articles, 85 countries, and a total of 299924 pregnant women. Our adjusted estimate for maternal GBS colonization worldwide was 18% (95% confidence interval [CI], 17%-19%), with regional variation (11%-35%), and lower prevalence in Southern Asia (12.5% [95% CI, 10%-15%]) and Eastern Asia (11% [95% CI, 10%-12%]). Bacterial serotypes I-V account for 98% of identified colonizing GBS isolates worldwide. Serotype III, associated with invasive disease, accounts for 25% (95% CI, 23%-28%), but is less frequent in some South American and Asian countries. Serotypes VI-IX are more common in Asia.

CONCLUSIONS

GBS colonizes pregnant women worldwide, but prevalence and serotype distribution vary, even after adjusting for laboratory methods. Lower GBS maternal colonization prevalence, with less serotype III, may help to explain lower GBS disease incidence in regions such as Asia. High prevalence worldwide, and more serotype data, are relevant to prevention efforts.

Group B Streptococcal Disease Worldwide for Pregnant Women, Stillbirths, and Children: Why, What, and How to Undertake Estimates?

Improving maternal, newborn, and child health is central to Sustainable Development Goal targets for 2030, requiring acceleration especially to prevent 5.6 million deaths around the time of birth. Infections contribute to this burden, but etiological data are limited. Group B Streptococcus (GBS) is an important perinatal pathogen, although previously focus has been primarily on liveborn children, especially early-onset disease. In this first of an 11-article supplement, we discuss the following: (1) Why estimate the worldwide burden of GBS disease? (2) What outcomes of GBS in pregnancy should be included? (3) What data and epidemiological parameters are required? (4) What methods and models can be used to transparently estimate this burden of GBS? (5) What are the challenges with available data? and (6) How can estimates address data gaps to better inform GBS interventions including maternal immunization? We review all available GBS data worldwide, including maternal GBS colonization, risk of neonatal disease (with/without intrapartum antibiotic prophylaxis), maternal GBS disease, neonatal/infant GBS disease, and subsequent impairment, plus GBS-associated stillbirth, preterm birth, and neonatal encephalopathy. We summarize our methods for searches, meta-analyses, and modeling including a compartmental model. Our approach is consistent with the World Health Organization (WHO) Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER), published in The Lancet and the Public Library of Science (PLoS). We aim to address priority epidemiological gaps highlighted by WHO to inform potential maternal vaccination.

Effects of Intrapartum Antibiotic Prophylaxis on Neonatal Acquisition of Group B Streptococci

OBJECTIVES

To assess the incidence of colonization with group B streptococci (GBS) among neonates as influenced by maternal GBS carriage and intrapartum antibiotic prophylaxis (IAP).

STUDY DESIGN

Between October 2014 and May 2015, nasopharyngeal and rectal swab samples were collected from 730 neonates at 1 week and 1 month after birth. GBS and capsular serotype were identified by real-time polymerase chain reaction and by culture. IAP at delivery was determined retrospectively from hospital records.

RESULTS

Sixty-four neonates (8.8%) were GBS-positive by real-time polymerase chain reaction and culture. Among neonates born to mothers who were GBS carriers (n = 107), 94.4% (101/107) had maternal IAP; 19.6% nonetheless were GBS-positive, compared with 6.5% of neonates born to noncarrier mothers (P <.01). Among neonates born to mothers receiving IAP, more were positive only at 1 month of age than at both 1 week and 1 month. The frequency of GBS in neonates born to mothers receiving IAP was significantly lower than that in neonates born to mothers not receiving IAP (P <.05). Capsular serotypes V (25%) and III (23.4%) were common, followed by Ib (15.6%), Ia (14.1%), II (7.8%), IV (6.3%), nontypeable (4.7%), and VI and VIII (each 1.6%).

CONCLUSIONS

Delayed colonization with GBS occurs in infants born to GBS carrier mothers receiving IAP. GBS should be considered in all infants at 1 month after birth with signs of infection.

SIgA, TGF-β1, IL-10, and TNFα in Colostrum Are Associated with Infant Group B Streptococcus Colonization

Background

Group B Streptococcus (GBS) is a major cause of mortality and morbidity in infants and is associated with transmission from a colonized mother at birth and via infected breastmilk. Although maternal/infant colonization with GBS is common, the majority of infants exposed to GBS remain unaffected. The association between breastmilk immune factors and infant colonization and disease prevention has not been elucidated.

Objectives

We have investigated the association between SIgA and cytokines in breastmilk and infant GBS colonization and clearance.

Methods

Mother/infant GBS colonization was determined in a prospective cohort of 750 Gambian mother/infant pairs followed to day 89 of life. Anti-GBS secretory IgA bound to the surface of whole bacteria was assessed by flow cytometry and a panel of 12 cytokines quantified by mesoscale discovery in colostrum, breastmilk and serum.

Results

Compared with infants receiving low anti-GBS SIgA in colostrum, infants receiving high anti-GBS SIgA were at decreased risk of GBS colonization for serotypes III and V. Infants colonized at day 6 were twice as likely to receive colostrum with high TGF-β1, TNFα, IL10, and IL-6 compared to uncolonized infants. Infants receiving high colostral TGF-β1, TNFα, and IL-6 had two-fold enhanced GBS clearance between birth and day 89.

Conclusion

Our results suggest that the infant GBS colonization risk diminishes with increasing anti-GBS SIgA antibody in breastmilk and that key maternally derived cytokines might contribute to protection against infant colonization. These findings might be leveraged to develop interventions including maternal vaccination that may reduce infant GBS colonization.

Group B Streptococcus causes severe sepsis in term neonates: 8 years experience of a major Chinese neonatal unit

BACKGROUND

In contrast to industrialized countries, the clinical characteristics of neonatal sepsis caused by Group B Streptococcus (GBS) are largely unexplored in China.

METHODS

A retrospective case series study was performed at a high-capacity neonatal unit in Shanghai, China from January 2008 to December 2015. Clinical characteristics of neonates with culture-proven GBS sepsis and antibiotic susceptibility of isolated strains were analyzed.

RESULTS

Forty-three term neonates were included during the study period. The majority (74.4%) had early-onset sepsis with symptoms of respiratory distress. Meningitis was significantly more common in lateonset sepsis than in early-onset sepsis (81.5% vs. 18.8%, P<0.0001). Approximately one third of all patients (n=16) developed severe sepsis, defined as sepsis with organ dysfunctions, and respiratory dysfunction/failure was the most common (32.6%). The in-hospital mortality rate of GBS sepsis was 4.7%. Neonates who progressed to severe sepsis had significantly lower pH level at the onset of symptoms than those who did not (7.26±0.12 vs. 7.39±0.05, P=0.006). Treatment of severe GBS sepsis required lots of medical resources including extracorporeal membrane oxygenation. All tested GBS strains were susceptible to penicillin, but the rate of resistance to clindamycin (84.0%) and erythromycin (88.0%) was high.

CONCLUSIONS

GBS as a pathogen for neonatal sepsis has been receiving little attention in China. Our data demonstrated that GBS sepsis was likely to be fulminant. Early recognition followed by antibiotics and adequate supportive therapies was critical for successful treatment. Chinese clinicians should be aware of GBS infection when treating neonatal sepsis, especially in the absence of universal maternal GBS screening.

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.

Maternal colonization with Staphylococcus aureus and Group B streptococcus is associated with colonization in newborns

OBJECTIVES

Although Staphylococcus aureus and Group B streptococcus (GBS) are major causes of neonatal sepsis in sub-Saharan Africa, it is unclear how these bacteria are transmitted to the neonate.

METHODS

In a cohort of 377 Gambian women and their newborns, nasopharyngeal swabs were collected at delivery (day 0), and 3, 6, 14 and 28 days later. Breast milk samples and vaginal swabs were collected from the mother. Staphylococcus aureus and GBS were isolated using conventional microbiological methods.

RESULTS

Most women were carriers of S. aureus (264 out of 361 with all samples collected, 73.1%) at some point during follow up and many were carriers of GBS (114 out of 361, 31.6%). Carriage of S. aureus was common in all three maternal sites and GBS was common in the vaginal tract and breast milk. Among newborns, carriage of S. aureus peaked at day 6 (238 out of 377, 63.1%) and GBS at day 3 (39 out of 377, 10.3%). Neonatal carriage of S. aureus at day 6 was associated with maternal carriage in the breast milk adjusted OR 2.54; 95% CI 1.45-4.45, vaginal tract (aOR 2.55; 95% CI 1.32-4.92) and nasopharynx (aOR 2.49; 95% CI 1.56-3.97). Neonatal carriage of GBS at day 6 was associated with maternal carriage in the breast milk (aOR 3.75; 95% CI 1.32-10.65) and vaginal tract (aOR 3.42; 95% CI 1.27-9.22).

CONCLUSIONS

Maternal colonization with S. aureus or GBS is a risk factor for bacterial colonization in newborns.

Association between functional antibody against Group B Streptococcus and maternal and infant colonization in a Gambian cohort

BACKGROUND

Vertical transmission of Group B Streptococcus (GBS) is a prerequisite for early-onset disease and a consequence of maternal GBS colonization. Disease protection is associated with maternally-derived anti-GBS antibody. Using a novel antibody-mediated C3b/iC3b deposition flow cytometry assay which correlates with opsonic killing we developed a model to assess the impact of maternally-derived functional anti-GBS antibody on infant GBS colonization from birth to day 60-89 of life.

METHODS

Rectovaginal swabs and cord blood (birth) and infant nasopharyngeal/rectal swabs (birth, day 6 and day 60-89) were obtained from 750 mother/infant pairs. Antibody-mediated C3b/iC3b deposition with cord and infant sera was measured by flow cytometry.

RESULTS

We established that as maternally-derived anti-GBS functional antibody increases, infant colonization decreases at birth and up to three months of life, the critical time window for the development of GBS disease. Further, we observed a serotype (ST)-dependent threshold above which no infant was colonized at birth. Functional antibody above the upper 95th confidence interval for the geometric mean concentration was associated with absence of infant GBS colonization at birth for STII (p<0.001), STIII (p=0.01) and STV (p<0.001). Increased functional antibody was also associated with clearance of GBS between birth and day 60-89.

CONCLUSIONS

Higher concentrations of maternally-derived antibody-mediated complement deposition are associated with a decreased risk of GBS colonization in infants up to day 60-89 of life. Our findings are of relevance to establish thresholds for protection following vaccination of pregnant women with future GBS vaccines.