Prevalence of Group B Streptococcus Colonization and Potential for Transmission by Casual Contact in Healthy Young Men and Women

Manning, Shannon D.; Neighbors, Katie; Tallman, Patricia; Gillespie, Brenda W.; Marrs, Carl F.; Borchardt, Stephanie M.; Baker, Carol J.; Pearlman, Mark D.; Foxman, Betsy

doi:10.1086/422321

Cited by 80 publications

(69 citation statements)

References 15 publications

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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). GBS has also been identified as the cause of bovine mastitis in up to 45% of symptomatic bovines (30).…”

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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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confidence: 99%

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

Springman

Lacher²,

et al. 2009

J Bacteriol

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“…Despite a recent decline in incidence, GBS remains a leading cause of neonatal mortality and morbidity in the United States (2,7,29,30). GBS colonizes the genitourinary and gastrointestinal tracts of about a third of healthy adult women (24). Neonatal disease results from transmission of the organism from the pregnant mother to the neonate.…”

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confidence: 99%

Population Structure of Invasive and Colonizing Strains of Streptococcus agalactiae from Neonates of Six U.S. Academic Centers from 1995 to 1999

Bohnsack¹,

Whiting²,

Gottschalk

et al. 2008

J Clin Microbiol

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The purpose of this study was to describe the population structure of group B streptococci (GBS) isolated from infected and colonized neonates during a prospective active-surveillance study of early-onset disease in six centers in the United States from July 1995 to June 1999 and to examine its relationship to bovine strains of GBS. The phylogenetic lineage of each GBS isolate was determined by multilocus sequence typing, and isolates were clustered into clonal complexes (CCs) using the eBURST software program. A total of 899 neonatal GBS isolates were studied, of which 129 were associated with invasive disease. Serotype Ia, Ib, and V isolates were highly clonal, with 92% to 96% of serotype Ia, Ib, and V isolates being confined to single clonal clusters. In contrast, serotype II and III isolates were each comprised of two major clones, with 39% of serotype II and 41% of serotype III isolates in CC 17 and 41% of serotype II and 54% of serotype III isolates in CC 19. Further analysis demonstrates that the CC 17 serotype II and III GBS are closely related to a previously described "ancestral" lineage of bovine GBS. While 120 (93%) of invasive GBS were confined to the same lineages that colonized neonates, 9 (7%) of the invasive GBS isolates were from rare lineages that comprised only 2.7% of colonizing lineages. These results are consistent with those for other geographic regions that demonstrate the highly clonal nature of GBS infecting and colonizing human neonates.Streptococcus agalactiae (group B streptococci [GBS]), a primary cause of bovine mastitis, emerged in the 1960s as a significant human pathogen that causes neonatal sepsis and meningitis (1). Despite a recent decline in incidence, GBS remains a leading cause of neonatal mortality and morbidity in the United States (2,7,29,30). GBS colonizes the genitourinary and gastrointestinal tracts of about a third of healthy adult women (24). Neonatal disease results from transmission of the organism from the pregnant mother to the neonate. Heavy colonization of the neonate and maternal chorioamnionitis are known risk factors for neonatal infection (10,20).GBS can be divided into nine serotypes based on the immunologic reactivity of the capsular polysaccharide. The structure of GBS capsular polysaccharide is determined by genes in the cps locus which encode enzymes responsible for the synthesis of the polysaccharides (8,34,35). Investigators using a variety of techniques have demonstrated that the population of GBS that colonizes and infects humans is comprised of a relatively small number of lineages (4, 12-16, 23, 26, 28, 31, 32). Each serotype is usually distributed among several different lineages, and each lineage may contain several different serotypes, indicating that serotype alone is not a sufficient marker to identify a phylogenetic lineage and suggesting that serotype switching occurs within lineages, presumably by horizontal transfer of cps genes (4,16,23).Multilocus sequence typing (MLST) has become the standard method for determining the population s...

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“…GBS is a common commensal organism in the female vaginal tract, where it is held in check by as yet unknown mechanisms [34,35]. When GBS comes in contact with epithelial or mucosal surfaces in a relatively immunocompromised host, such as a neonate or an elderly or diabetic adult, it has the capacity to mount an invasive infection.…”

Section: Discussionmentioning

confidence: 99%

Role of Toll-like receptor 2 in innate resistance to Group B Streptococcus

Asplin

Carl

Way

et al. 2008

Microbial Pathogenesis

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The Gram-positive bacterium Group B Streptococcus (GBS) is an important cause of serious neonatal and adult infections. Toll-like receptor 2 (TLR2) recognizes components of the cell wall of Grampositive bacteria and is critical for defense against certain invasive pathogens. In GBS, penicillinbinding protein 1a (PBP1a), encoded by ponA, is required for virulence. PBPs participate in cell wall synthesis and in previous studies; the absence of PBP1a was shown to result in subtle changes in the cell wall ultrastructure. Here, we examine the role of TLR2 in defense against GBS infection and the impact of mutation of ponA on TLR2-mediated host responses. We demonstrate TLR2-recognition of both WT GBS and the ponA mutant in vitro. TLR2 −/− mice were significantly more susceptible than WT mice to infection with either strain of GBS, indicating a crucial role for TLR2 in defense against GBS. Additionally, the ponA mutant was severely attenuated for virulence in both strains of mice. The mutation in ponA did not affect cytokine expression by WT or TLR2 −/− mice. These data indicate that TLR2 is required for host defense against GBS and this response is unaffected by the absence of PBP1a and the resultant changes in cell wall ultrastructure.

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Prevalence of Group B Streptococcus Colonization and Potential for Transmission by Casual Contact in Healthy Young Men and Women

Cited by 80 publications

References 15 publications

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

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

Population Structure of Invasive and Colonizing Strains of Streptococcus agalactiae from Neonates of Six U.S. Academic Centers from 1995 to 1999

Role of Toll-like receptor 2 in innate resistance to Group B Streptococcus

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