scholarly journals Molecular epidemiology of infections caused by group B Streptococcus in pregnant women and newborns, and development of preventive vaccines

2018 ◽  
Vol 67 (5) ◽  
pp. 62-73
Author(s):  
Vasilisa A. Vasilyeva ◽  
Elena V. Shipitsyna ◽  
Kira V. Shalepo ◽  
Alevtina M. Savicheva
Keyword(s):  
Capsular Polysaccharide ◽  
Vaccine Development ◽  
Current Knowledge ◽  
Group B Streptococcus ◽  
Epidemiological Data ◽  
Group B Streptococci ◽  
Group B ◽  
Sequence Types ◽  
Experimental Immunization ◽  
Selection Of

Hypothesis/aims of study. The present analysis was undertaken to summarize current knowledge about molecular properties of group B streptococci (GBS), emphasizing potential targets of vaccines against neonatal GBS infection. Study design, materials, and methods. This review is based on articles published mainly in the last ten years. Results. Epidemiological data on serotypes, multilocus sequence types, clonal complexes of GBS and their relationship are presented. Genetic events in GBS populations indicate significant obstacles to vaccine development. We described key properties of major GBS virulence factors, such as capsular polysaccharide, pili, and cell adhesion molecules, as well as results of experimental immunization on their basis. Conclusion. The population of invasive GBS strains is molecularly and genetically heterogeneous, which complicates selection of vaccine targets. Capsular switching, a low level of immunogenicity and variability of population composition are the most important factors that necessitate the accumulation and monitoring of molecular epidemiological data.

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

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1606
Author(s):  
Sarah Shabayek ◽  
Patricia Ferrieri ◽  
Barbara Spellerberg
Keyword(s):  
Group B Streptococcus ◽  
Epidemiological Data ◽  
Protein Vaccine ◽  
African Countries ◽  
Suitable Alternative ◽  
Promising Alternative ◽  
Molecular Sequence ◽  
Resource Limited ◽  
Group B ◽  
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.

scholarly journals Distribution of Pilus Islands in Streptococcus agalactiae That Cause Human Infections: Insights into Evolution and Implication for Vaccine Development

2012 ◽  
Vol 20 (2) ◽  
pp. 313-316 ◽  
Author(s):  
E. R. Martins ◽  
A. Andreu ◽  
J. Melo-Cristino ◽  
M. Ramirez
Keyword(s):  
Streptococcus Agalactiae ◽  
Vaccine Development ◽  
Group B Streptococcus ◽  
Human Pathogens ◽  
Content Type ◽  
The Stability ◽  
Group B ◽  
Human Infections ◽  
Sequence Types

ABSTRACTAt least one pilus island, PI-1 (70%), PI-2a (79%), or PI-2b (21%), was found among 898Streptococcus agalactiae(group B streptococcus [GBS]) isolates recovered from humans, supporting the use of pilus proteins in vaccines. The stability and dominance of PI-1 and PI-2a in multiple serotypes and founder multilocus sequence types disseminated worldwide suggest it could be the PI combination present in ancestral GBS human pathogens.

scholarly journals Evaluation of procedures for typing of group B Streptococcus: a retrospective study

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3105 ◽  
Author(s):  
Hans-Christian Slotved ◽  
Steen Hoffmann
Keyword(s):  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Latex Agglutination ◽  
Genotype Distribution ◽  
Group B Streptococci ◽  
The Difference ◽  
Group B ◽  
Streptococcus A ◽  
Precipitation Test ◽  
Latex Test

Background This study evaluates two procedures for typing of Streptococcus agalactiae (group B streptococci; GBS) isolates, using retrospective typing data from the period 2010 to 2014 with a commercial latex agglutination test (latex test) and the Lancefield precipitation test (LP test). Furthermore, the genotype distribution of phenotypically non-typable (NT) GBS isolates is presented. We also raise the awareness, that the difference in typing results obtained by phenotypical methods and genotype based methods may have implications on vaccine surveillance in case a GBS vaccine is introduced. Methods A total of 616 clinical GBS isolates from 2010 to 2014 were tested with both a latex test and the LP test. Among these, 66 isolates were genotyped by PCR, including 41 isolates that were phenotypically NT. Results The latex test provided a serotype for 83.8% of the isolates (95% CI [80.7–86.6]) compared to 87.5% (95% CI [84.6–90.0]) obtained by the LP method. The two assays provided identical capsular identification for all sero-typeable isolates (excluding NT isolates). The PCR assay provided a genotype designation to the 41 isolates defined as phenotypically NT isolates. Discussion We found that the latex test showed a slightly lower identification percentage than the LP test. Our recommendation is to use the latex agglutination as the routine primary assay for GBS surveillance, and then use the more labour intensive precipitation test on the NT isolates to increase the serotyping rate. A genotype could be assigned to all the phenotypically NT isolates, however, as a consequence genotyping will overestimate the coverage from possible future capsular polysaccharide based GBS vaccines.

Associations between capsular serotype, multilocus sequence type, and macrolide resistance inStreptococcus agalactiaeisolates from Japanese infants with invasive infections

2013 ◽  
Vol 142 (4) ◽  
pp. 812-819 ◽  
Author(s):  
M. MOROZUMI ◽  
T. WAJIMA ◽  
Y. KUWATA ◽  
N. CHIBA ◽  
K. SUNAOSHI ◽  
...  
Keyword(s):  
Clonal Complex ◽  
Vaccine Development ◽  
Late Onset ◽  
Group B Streptococcus ◽  
Sequence Type ◽  
Macrolide Resistance ◽  
Invasive Infections ◽  
Resistant Strains ◽  
Group B ◽  
Sequence Types

SUMMARYStreptococcus agalactiae(group B streptococcus; GBS) isolates (n = 150) from infants with invasive infections between 2006 and 2011 were analysed for capsular serotype, multilocus sequence type, and antibiotic susceptibility. In cases with late-onset disease (n = 115), primary meningitis was predominant (62·6%), but represented only 39·1% in cases with early-onset disease (n = 23). The most common serotype was III (58·7%), followed by Ia (21·3%) and Ib (12·7%). Sequence types (STs) of serotype III strains included ST17 (50·0%), ST19 (26·1%), ST335 (18·2%), ST27 (4·5%), and ST1 (1·1%). Predominant STs of serotypes Ia and Ib were ST23 (81·3%) and ST10 (84·2%), respectively. No penicillin-resistant strains were detected, but 22·0% of strains hadmef(A/E),erm(A), orerm(B) genes, which mediate macrolide resistance. A new ST335, possessing anmef(A/E) gene belonging to clonal complex 19 gradually increased in frequency. Improved prevention of invasive GBS infections in infants requires timely identification, and ultimately vaccine development.

scholarly journals Immunization with C5a Peptidase or Peptidase-Type III Polysaccharide Conjugate Vaccines Enhances Clearance of Group B Streptococci from Lungs of Infected Mice

2002 ◽  
Vol 70 (11) ◽  
pp. 6409-6415 ◽  
Author(s):  
Qi Cheng ◽  
Steven Debol ◽  
Hong Lam ◽  
Ron Eby ◽  
Lorri Edwards ◽  
...  
Keyword(s):  
Tetanus Toxoid ◽  
Capsular Polysaccharide ◽  
Vaccine Development ◽  
Surface Protein ◽  
Histological Evaluation ◽  
Group B Streptococci ◽  
Type Iii ◽  
Rapid Clearance ◽  
Group B ◽  
The Impact

ABSTRACT Group B streptococci (GBS) are among the most common causes of life-threatening neonatal infections. Vaccine development since the late 1970s has focused on the capsular polysaccharides, but a safe, effective product is still not available. Our quest for a vaccine turned to the streptococcal C5a peptidase (SCPB). This surface protein is antigenically conserved across most if not all serotypes. A murine model was used to assess the impact of SCPB on clearance of GBS from the lungs of intranasally infected animals. Mutational inactivation of SCPB resulted in more-rapid clearance of streptococci from the lung. Immunization with recombinant SCPB alone or SCPB conjugated to type III capsular polysaccharide produced serotype-independent protection, which was evidenced by more-rapid clearance of the serotype VI strain from the lungs. Immunization of mice with tetanus toxoid-type III polysaccharide conjugate did not produce protection, confirming that protection induced by SCPB conjugates was independent of type III polysaccharide antigen. Histological evaluation of lungs from infected mice revealed that pathology in animals immunized with SCPB or SCPB conjugates was significantly less than that in animals immunized with a tetanus toxoid-polysaccharide conjugate. These experiments suggest that inclusion of C5a peptidase in a vaccine will both add another level to and broaden the spectrum of the protection of a polysaccharide vaccine.

scholarly journals Antibody against Surface-Bound C5a Peptidase Is Opsonic and Initiates Macrophage Killing of Group B Streptococci

2001 ◽  
Vol 69 (4) ◽  
pp. 2302-2308 ◽  
Author(s):  
Qi Cheng ◽  
Brian Carlson ◽  
Sub Pillai ◽  
Ron Eby ◽  
Lorri Edwards ◽  
...  
Keyword(s):  
Whole Blood ◽  
Capsular Polysaccharide ◽  
Vaccine Development ◽  
Primary Cultures ◽  
Surface Protein ◽  
Mouse Bone Marrow ◽  
Group B Streptococci ◽  
Protective Antibodies ◽  
Group B

ABSTRACT The capsular polysaccharides of group B streptococci (GBS) are a primary focus of vaccine development. Immunogenicity and long-lasting protection are best achieved by conjugating polysaccharides to a T-cell-dependent protein antigen. Streptococcal C5a peptidase (SCPB) is a conserved surface protein that is expressed by all streptococcal serotypes tested to date, and it is a possible carrier protein that could itself induce a protective immune response. Clearance of GBS from lungs, mucosal surfaces, or blood probably depends on the opsonophagocytic response of tissue-specific macrophages and polymorphonuclear leukocytes (PMNs). In this study, we examined the potential of antibody directed against SCPB from a serotype II strain to enhance the capacity of mouse bone marrow macrophages (from primary cultures) and human PMNs in whole blood to kill GBS in vitro. Our experiments demonstrated that Streptococcus serotypes Ia, Ib, II, III, and V, preopsonized with anti-SCPB antibody, were killed more rapidly by cultured macrophages and PMNs in whole blood than were nonopsonized GBS. The increased rate of killing was accompanied by an increased macrophage oxidative burst. Furthermore, opsonization was serotype transparent. Immunization with SCPB conjugated to capsular polysaccharide type III produced polysaccharide-specific antibodies. It is interesting that this antiserum promoted serotype-independent killing of streptococci. These data support the use of SCPB in a GBS polysaccharide conjugate vaccine. SCPB not only enhanced the immunogenicity of polysaccharide components of the vaccine, but it might also induce additional serotype-independent protective antibodies.

scholarly journals Development and Validation of Enzyme-Linked Immunosorbent Assay for Group B Streptococcal Polysaccharide Vaccine

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 545
Author(s):  
A-Yeung Jang ◽  
Min-Joo Choi ◽  
Yong Zhi ◽  
Hyun-Jung Ji ◽  
Ji-Yun Noh ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Large Scale ◽  
Capsular Polysaccharide ◽  
Vaccine Development ◽  
Group B Streptococcus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Igg Antibody ◽  
Logistic Method ◽  
Group B

Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of neonatal sepsis and meningitis in infants. Limitations of prenatal GBS screening and intrapartum antibiotic prophylaxis render developing GBS vaccines a high priority. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) for the practical and large-scale evaluation of GBS capsular polysaccharide (PS) vaccine immunogenicity against three main serotypes, Ia, III, and V. GBS-ELISA was developed and subsequently validated using a standardized curve-fitting four-parameter logistic method. Specificity was measured using adsorption of serum with homologous and heterologous PS. Homologous adsorption showed a ≥75% inhibition of all three serotypes, whereas with heterologous PS, IgG GBS-ELISA inhibited only ≤25% of serotypes III and V. However, with serotype Ia, IgG antibody levels decreased by >50%, even after adsorption with heterologous PS (III or V). In comparison, the inhibition opsonophagocytic killing assay (OPA) of serotypes Ia GBS exhibited a reduction in opsonophagocytic activity of only 20% and 1.1% for serotypes III and V GBS, respectively. The precision of the GBS-ELISA was assessed in five independent experiments using four serum samples. The coefficient of variation was <5% for all three serotypes. This standardized GBS-ELISA would be useful for GBS vaccine development and its evaluation.

scholarly journals Trends in molecular characteristics and antimicrobial resistance of group B streptococci: a multicenter study in Serbia, 2015–2020

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dusan Kekic ◽  
Ina Gajic ◽  
Natasa Opavski ◽  
Milan Kojic ◽  
Goran Vukotic ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Late Onset ◽  
Group B Streptococcus ◽  
Neonatal Morbidity ◽  
Disease Rate ◽  
Molecular Characteristics ◽  
Group B Streptococci ◽  
Live Births ◽  
Invasive Infections ◽  
Group B

AbstractGroup B Streptococcus (GBS) is a major cause of neonatal morbidity and mortality. Serbia has not fully implemented preventive measures against GBS neonatal diseases. Therefore, we aimed to assess the maternal GBS colonisation and invasive neonatal disease rate, to reveal the trends of antimicrobial resistance and serotype distribution of GBS from various patient groups. Randomly selected non-invasive (n = 991) and all invasive GBS (n = 80) collected throughout Serbia from 2015 to 2020 were tested for antimicrobial susceptibility, capsular typing, and hvgA detection. Overall, 877/5621 (15.6%) pregnant women were colonised with GBS. Invasive GBS infections incidence in infants (0.18/1000 live births) showed a decreasing trend (0.3 to 0.1/1000 live births). Type III was overrepresented in infants with invasive infections (n = 35, 58.3%), whereas type V predominated among colonised adults (n = 224, 25.5%) and those with noninvasive (n = 37, 32.5%) and invasive infections (n = 8, 40%). The hypervirulent clone III/ST17 was highly associated with invasive infections (n = 28, 35%), particularly late-onset disease (n = 9, 47.4%), showing an increase from 12.3 to 14.8%. The GBS resistance to erythromycin and clindamycin was 26.7% and 22.1%, respectively, with an upward trend. The emergence of the hypervirulent clone III/ST17 and the escalation in GBS resistance highlight an urgent need for continuous monitoring of GBS infections.

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