Antibodies to Capsular Polysaccharides of Group B<i>Streptococcus</i>in Pregnant Canadian Women: Relationship to Colonization Status and Infection in the Neonate

Davies, H. Dele; Adair, Carol E.; McGeer, Allison; Ma, Doreen; Robertson, Sheila; Mucenski, Melissa; Kowalsky, Laura; Tyrell, Gregory J; Baker, Carol J.

doi:10.1086/322029

Cited by 102 publications

(82 citation statements)

References 45 publications

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“…Indeed, previous studies have reported that CPS type III GBS strains induce a lower maternal antibody response 34 and are more virulent. Since newborn infants rely on the transfer of maternal antibodies for defense against infections early in life, the low antibody response to type III strains could explain the high rate of type III infections.…”

Section: Cps Type Percent Survivalmentioning

confidence: 98%

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

et al. 2016

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Group B Streptococcus (GBS), a leading cause of neonatal sepsis and meningitis, asymptomatically colonizes up to 30% of women and can persistently colonize even after antibiotic treatment. Previous studies have shown that GBS resides inside macrophages, but the mechanism by which it survives remains unknown. Here, we examined the ability of 4 GBS strains to survive inside macrophages and then focused on 2 strains belonging to sequence type (ST)-17 and ST-12, to examine persistence in the presence of antibiotics. A multiple stress medium was also developed using several stressors found in the phagosome to assess the ability of 30 GBS strains to withstand phagosomal stress. The ST-17 strain was more readily phagocytosed and survived intracellularly longer than the ST-12 strain, but the ST-12 strain was tolerant to ampicillin unlike the ST-17 strain. Exposure to sub-inhibitory concentrations of ampicillin and erythromycin increased the level of phagocytosis of the ST-17 strain, but had no effect on the ST-12 strain. In addition, blocking acidification of the phagosome decreased the survival of the ST-17 strain indicating a pHdependent survival mechanism for the ST-17 strain. Congruent with the macrophage experiments, the ST-17 strain had a higher survival rate in the multiple stress medium than the ST-12 strain, and overall, serotype III isolates survived significantly better than other serotypes. These results indicate that diverse GBS strains may use differing mechanisms to persist and that serotype III strains are better able to survive specific stressors inside the phagosome relative to other serotypes.

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Section: Cps Type Percent Survivalmentioning

confidence: 98%

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

et al. 2016

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“…Alternatively (though less desirably), surrogate immunological measures of clinical efficacy based on maternal and neonatal serotype-specific IgG antibody may be sufficient endpoints. 25,48 RECOMMENDATIONS What is the best preventive strategy for the UK? Table 7 summarizes estimates of the numbers of deaths and cases of serious disability estimated to be prevented by each of the three preventive strategies.…”

Section: Conducting a Trialmentioning

confidence: 99%

The prevention of neonatal group B streptococcal disease: a report by a working group of the Medical Screening Society

et al. 2005

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Streptococcus agalactiae, or Lancefield group B streptococcus (GBS), is the most frequent cause of serious bacterial sepsis, including neonatal meningitis, in UK neonates. Early-onset neonatal GBS infection, but not late-onset, can be prevented by screening to identify high-risk pregnancies and administering penicillin during delivery. A vaccine has been developed as an alternative means of prevention but it is awaiting a randomized trial before being available for general use. In this review we examine the published literature to assess the morbidity and mortality attributable to neonatal GBS infection, quantify the screening performance of the two alternative modes of screening (microbiological and risk factor based), review the evidence on the efficacy of the vaccine, and estimate the numbers of deaths and cases of serious disability that each strategy in turn might prevent in the UK, in order to assess the most effective means of prevention for the UK.

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“…Maternal GBS colonization is a main risk factor for neonatal disease, and roughly 20 to 40% of pregnant women are colonized (14,23). Colonization rates of up to 31% and 34% have been documented in young men (4) and nonpregnant women (4,42), respectively, whereas a rate of 22% has been observed in individuals over 65 years of age (18).…”

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confidence: 99%

Selection, Recombination, and Virulence Gene Diversity among Group B Streptococcal Genotypes

Springman

Lacher²,

et al. 2009

J Bacteriol

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Transmission of group B Streptococcus (GBS) from mothers to neonates during childbirth is a leading cause of neonatal sepsis and meningitis. Although subtyping tools have identified specific GBS phylogenetic lineages that are important in neonatal disease, little is known about the genetic diversity of these lineages or the roles that recombination and selection play in the generation of emergent genotypes. Here, we examined genetic variation, selection, and recombination in seven multilocus sequence typing (MLST) loci from 94 invasive, colonizing, and bovine strains representing 38 GBS sequence types and performed DNA sequencing and PCR-based restriction fragment length polymorphism analysis of several putative virulence genes to identify gene content differences between genotypes. Despite the low level of diversity in the MLST loci, a neighbor net analysis revealed a variable range of genetic exchange among the seven clonal complexes (CCs) identified, suggesting that recombination is partly responsible for the diversity observed between genotypes. Recombination is also important for several virulence genes, as some gene alleles had evidence for lateral gene exchange across divergent genotypes. The CC-17 lineage, which is associated with neonatal disease, is relatively homogeneous and therefore appears to have diverged independently with an exclusive set of virulence characteristics. These data suggest that different GBS genetic backgrounds have distinct virulence gene profiles that may be important for disease pathogenesis. Such profiles could be used as markers for the rapid detection of strains with an increased propensity to cause neonatal disease and may be considered useful vaccine targets.Group B Streptococcus (GBS) is a leading cause of neonatal sepsis, pneumonia, and meningitis (51) and causes infections in pregnant women, nonpregnant adults, and the elderly with underlying medical conditions. Maternal GBS colonization is a main risk factor for neonatal disease, and roughly 20 to 40% of pregnant women are colonized (14, 23). Colonization rates of up to 31% and 34% have been documented in young men (4) and nonpregnant women (4, 42), respectively, whereas a rate of 22% has been observed in individuals over 65 years of age (18). GBS has also been identified as the cause of bovine mastitis in up to 45% of symptomatic bovines (30). Nine distinct polysaccharide capsule types (serotypes) are known, and the serotype distribution varies by population.The genetic diversity of GBS populations has been studied using a variety of different methods, including restriction fragment length polymorphism (RFLP) (24), ribotyping (5, 25), pulsed-field gel electrophoresis (49), multilocus enzyme electrophoresis (MLEE) (45), random amplification of polymorphic DNA (36), restriction digestion pattern (RDP) typing (53), and multilocus sequence typing (MLST) (28). By utilizing methods that focus on conserved genetic changes within GBS strains, virulent GBS clones that have diversified genetically can be identified. Both MLEE an...

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Antibodies to Capsular Polysaccharides of Group BStreptococcusin Pregnant Canadian Women: Relationship to Colonization Status and Infection in the Neonate

Cited by 102 publications

References 45 publications

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

The prevention of neonatal group B streptococcal disease: a report by a working group of the Medical Screening Society

Selection, Recombination, and Virulence Gene Diversity among Group B Streptococcal Genotypes

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