scholarly journals Infection-Derived Enterococcus faecalisStrains Are Enriched in esp, a Gene Encoding a Novel Surface Protein

1999 ◽  
Vol 67 (1) ◽  
pp. 193-200 ◽  
Author(s):  
Viswanathan Shankar ◽  
Arto S. Baghdayan ◽  
Mark M. Huycke ◽  
Gunnar Lindahl ◽  
Michael S. Gilmore
Keyword(s):  
Surface Protein ◽  
Group B Streptococci ◽  
Gene Encoding ◽  
Repeat Units ◽  
Enterococcal Species ◽  
Alternate Forms ◽  
Selection For ◽  
Group B ◽  
High Degree ◽  
Organizational Similarity

ABSTRACT We report the identification of a new cell wall-associated protein of Enterococcus faecalis. Studies on the distribution of the gene encoding this novel surface protein, Esp, reveal a significant (P < 0.001) enrichment in infection-derived E. faecalis isolates. Interestingly, the esp gene was not identified in any of 34 clinical E. faecium isolates or in 4 other less pathogenic enterococcal species tested. Analysis of the structural gene among various E. faecalis isolates reveals the existence of alternate forms of expression of the Esp protein. The deduced primary structure of the Esp protein from strain MMH594, inferred to be 1,873 amino acids (aa) with a predicted mass of ∼202 kDa, reveals a core region consisting of repeat units that make up 50% of the protein. Esp bears global organizational similarity to the Rib and C alpha proteins of group B streptococci. Identity among Esp, Rib, and C alpha proteins is strikingly localized to a stretch of 13 aa within repeats of similar length. The high degree of conservation of this 13-residue sequence suggests that it plays an important role in the natural selection for this trait among infection-derived E. faecalis and group B streptococcal isolates.

scholarly journals Epidemiological aspects of group B streptococci of bovine and human origin

1996 ◽  
Vol 117 (3) ◽  
pp. 417-422 ◽  
Author(s):  
N. E. Jensen ◽  
F. M. Aarestrup
Keyword(s):  
Streptococcus Agalactiae ◽  
Double Diffusion ◽  
Restriction Enzymes ◽  
Group B Streptococci ◽  
Gene Encoding ◽  
Genetic Changes ◽  
Lactose Fermentation ◽  
Phenotypic Variations ◽  
Group B ◽  
Reference Strains

SummaryRestriction fragment length polymorphism of the gene encoding rRNA (ribotyping) was used in combination with conventional epidemiological markers to study phenotypic variations amongStreptococcus agalactiaeof bovine origin and the possible epidemiological interrelationship between the bovine and human reservoirs ofStreptococcus agalactiae.The bovine material constituted 53 strains (9 antigen combinations) isolated from 11 herds. Herds with a uniform as well as heterogenic antigenic pattern were included. Furthermore, strains isolated in the course of time from the same persistently infected quarters were examined. The human material constituted 16 strains, 4 each of 4 serotypes, isolated from healthy carriers. Finally, nine serotype- and the group reference strains were examined. All strains were serotyped by double diffusion in agarose gel, biotyped (lactose ±), and ribotyped using two restriction enzymes,HindIII andHhaI.All isolates could be typed by ribotyping and seven ribotypes were identified among the reference strains. The restriction enzymes used alone or in combination gave typing results that allowed discrimination between and within serotype. Combined use of serotype,HindIII andHhaI ribotypes produced 11 types among the 16 human strains. Ribotype analysis discriminated between herds infected with the same serotype. Strains of varying antigenic patterns from the same herd had the same ribotype. Phenotypic variations in serotype observed in persistent intramammary infection were not related to genetic changes as monitored by ribotype. Two ribotypes were represented among both bovine and human strains. The discriminating capability of lactose fermentation was of limited value.

scholarly journals A unique serine-rich repeat protein (Srr-2) and novel surface antigen (ε) associated with a virulent lineage of serotype III Streptococcus agalactiae

Microbiology ◽  
2006 ◽  
Vol 152 (4) ◽  
pp. 1029-1040 ◽  
Author(s):  
Kyle N. Seifert ◽  
Elisabeth E. Adderson ◽  
April A. Whiting ◽  
John F. Bohnsack ◽  
Paula J. Crowley ◽  
...  
Keyword(s):  
Surface Antigen ◽  
Invasive Disease ◽  
Group B Streptococci ◽  
Gene Encoding ◽  
Repeat Protein ◽  
Encoding Gene ◽  
Group B ◽  
Mouse Model Of Infection ◽  
Highly Virulent

Group B streptococci (GBS) are pathogens of both neonates and adults, with serotype III strains in particular being associated with invasive disease and meningitis. In this study, a novel GBS surface antigen, ε, was found to be co-expressed with the previously reported δ antigen on an identical subset of serotype III GBS. Expression of δ/ε on the surface of serotype III GBS was shown to distinguish the restriction digest pattern (RDP) III-3 and multilocus sequence typing (ST)-17 lineage. ε-Specific antibodies were reactive with a unique, high-molecular-mass, serine-rich repeat protein (Srr-2) found exclusively in RDP III-3 strains. The gene encoding Srr-2 was located within a putative accessory secretory locus that included secY2 and secA2 homologues and had a genetic organization similar to that of the secY2/A2 locus of staphylococci. In contrast, serotype III δ/ε-negative strains and strains representative of serotypes Ia, Ib, Ic and II shared a common Srr-encoding gene, srr-1, and an organization of the secY2/A2 locus similar to that of previously reported serotype Ic, δ/ε-negative serotype III and serotype V GBS strains. Representative serotype III δ/ε-positive strains had LD90 values 3–4 logs less than those of serotype III δ/ε-negative strains in a neonatal mouse model of infection. These results indicate that the RDP III-3/ST-17 lineage expresses Srr-2 and is highly virulent in an in vivo model of neonatal sepsis.

scholarly journals Genetic diversity of the C protein β-antigen gene and its upstream regions within clonally related groups of type Ia and Ib group B streptococci

Microbiology ◽  
2006 ◽  
Vol 152 (3) ◽  
pp. 771-778 ◽  
Author(s):  
Noriyuki Nagano ◽  
Yukiko Nagano ◽  
Ryuichi Nakano ◽  
Ryoichi Okamoto ◽  
Matsuhisa Inoue
Keyword(s):  
Genetic Diversity ◽  
Response Regulator ◽  
Surface Protein ◽  
Premature Termination Codon ◽  
Factor H ◽  
Binding Region ◽  
Group B Streptococci ◽  
C Protein ◽  
Expression Levels ◽  
Group B

C protein β antigen (Bac), a surface protein of group B streptococci (GBS), is known to concurrently bind the Fc portion of IgA and factor H (FH). The authors' previous work has demonstrated that mRNA expression levels show diversity among clonally related strains containing genes (bac) encoding Bac, with high expression noted in invasive strains. In this study, the bac gene and upstream regions containing putative promoters, three ORFs and an IS1381 insertion sequence were characterized. Three invasive strains showed high bac expression levels and did not show any notable mutations except one strain producing Bac that was able to bind FH but not IgA. A deletion of 51 amino acid residues, including part of the Bac IgA-binding region, was identified and hypothesized to contribute to the loss of the IgA-binding ability of this strain. A vaginal strain that showed somewhat higher bac expression levels and produced Bac lacking immunoreactivity contained an 11 bp deletion, which generated a premature termination codon, in the region preceding the IgA-binding region. In another vaginal strain that did not express bac, disruption of the upstream ORFs of the sensor histidine kinase and DNA-binding response regulator, due to frameshift mutations, was noted although it is not known whether these proteins directly affect bac expression levels. An IS1381 insertion into the promoter region was found in another vaginal strain that showed low expression levels and produced Bac with a significantly larger proline-rich repeat region. These results demonstrate considerable genetic diversity of the bac and upstream regions of invasive and noninvasive GBS, which may contribute to the variability of bac expression levels among those strains.

scholarly journals Whole-Genome Comparison Uncovers Genomic Mutations between Group B Streptococci Sampled from Infected Newborns and Their Mothers

2015 ◽  
Vol 197 (20) ◽  
pp. 3354-3366 ◽  
Author(s):  
Alexandre Almeida ◽  
Adrien Villain ◽  
Caroline Joubrel ◽  
Gérald Touak ◽  
Elisabeth Sauvage ◽  
...  
Keyword(s):  
Human Blood ◽  
Surface Protein ◽  
Genome Comparison ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Neonatal Infections ◽  
Group B Streptococci ◽  
Content Type ◽  
Whole Genome Comparison ◽  
Group B

ABSTRACTStreptococcus agalactiae(group BStreptococcusor GBS), a commensal of the human gut and genitourinary tract, is a leading cause of neonatal infections, in which vertical transmission from mother to child remains the most frequent route of contamination. Here, we investigated whether the progression of GBS from carriage to disease is associated with genomic adaptation. Whole-genome comparison of 47 GBS samples from 19 mother-child pairs uncovered 21 single nucleotide polymorphisms (SNPs) and seven insertions/deletions. Of the SNPs detected, 16 appear to have been fixed in the population sampled whereas five mutations were found to be polymorphic. In the infant strains, 14 mutations were detected, including two independently fixed variants affecting thecovRSlocus, which is known to encode a major regulatory system of virulence. A one-nucleotide insertion was also identified in the promoter region of the highly immunogenic surface protein Rib gene. Gene expression analysis after incubation in human blood showed that these mutations influenced the expression of virulence-associated genes. Additional identification of three mutated strains in the mothers' milk raised the possibility of the newborns also being a source of contamination for their mothers. Overall, our work showed that GBS strains in carriage and disease scenarios might undergo adaptive changes following colonization. The types and locations of the mutations found, together with the experimental results showing their phenotypic impact, suggest that those in a context of infection were positively selected during the transition of GBS from commensal to pathogen, contributing to an increased capacity to cause disease.IMPORTANCEGroup BStreptococcus(GBS) is a major pathogen responsible for neonatal infections. Considering that its colonization of healthy adults is mostly asymptomatic, the mechanisms behind its switch from a commensal to an invasive state are largely unknown. In this work, we compared the genomic profile of GBS samples causing infections in newborns with that of the GBS colonizing their mothers. Multiple mutations were detected, namely, within key virulence factors, including the response regulator CovR and surface protein Rib, potentially affecting the pathogenesis of GBS. Their overall impact was supported by differences in the expression of virulence-associated genes in human blood. Our results suggest that during GBS's progression to disease, particular variants are positively selected, contributing to the ability of this bacterium to infect its host.

Expression of Group B Protective Surface Protein (BPS) by Invasive and Colonizing Isolates of Group B Streptococci

2014 ◽  
Vol 69 (6) ◽  
pp. 894-898
Author(s):  
Aurea E. Flores ◽  
G. S. Chhatwal ◽  
Sharon L. Hillier ◽  
Carol J. Baker ◽  
Patricia Ferrieri
Keyword(s):  
Surface Protein ◽  
Group B Streptococci ◽  
Group B

scholarly journals Alpha C Protein as a Carrier for Type III Capsular Polysaccharide and as a Protective Protein in Group B Streptococcal Vaccines

1999 ◽  
Vol 67 (5) ◽  
pp. 2491-2496 ◽  
Author(s):  
Claudia Gravekamp ◽  
Dennis L. Kasper ◽  
Lawrence C. Paoletti ◽  
Lawrence C. Madoff
Keyword(s):  
Conjugate Vaccine ◽  
Tetanus Toxoid ◽  
Capsular Polysaccharide ◽  
Protein A ◽  
Surface Protein ◽  
Negative Control ◽  
Group B Streptococci ◽  
C Protein ◽  
Type Iii ◽  
Group B

ABSTRACT The alpha C protein, a protective surface protein of group B streptococci (GBS), is present in most non-type III GBS strains. Conjugate vaccines composed of the alpha C protein and type III capsular polysaccharide (CPS) might be protective against most GBS infections. In this study, the type III CPS was covalently coupled to full-length, nine-repeat alpha C protein (resulting in III-α9r conjugate vaccine) or to two-repeat alpha C protein (resulting in III-α2r conjugate vaccine) by reductive amination. Initial experiments with the III-α9r vaccine showed that it was poorly immunogenic in mice with respect to both vaccine antigens and was suboptimally efficacious in providing protection in mice against challenge with GBS. Therefore, modified vaccination protocols were used with the III-α2r vaccine. Female mice were immunized three times with 0.5, 5, or 20 μg of the III-α2r vaccine with an aluminum hydroxide adjuvant and bred. Ninety-five percent of neonatal mice born to dams immunized with the III-α2r vaccine survived challenge with GBS expressing type III CPS, and 60% survived challenge with GBS expressing wild-type (nine-repeat) alpha C protein; 18 and 17%, respectively, of mice in the negative control groups survived (P, <0.0001). These protection levels did not differ significantly from those obtained with the type III CPS-tetanus toxoid conjugate vaccine and the unconjugated two-repeat alpha C protein, which protected 98 and 58% of neonates from infection with GBS expressing type III CPS or the alpha C protein, respectively. Thus, the two-repeat alpha C protein in the vaccine was immunogenic and simultaneously enhanced the immunogenicity of type III CPS. III-α vaccines may be alternatives to GBS polysaccharide-tetanus toxoid vaccines, eliciting additional antibodies protective against GBS infection.

scholarly journals Streptococcus agalactiae Alpha-Like Protein 1 Possesses Both Cross-Reacting and Alp1-Specific Epitopes

2011 ◽  
Vol 18 (8) ◽  
pp. 1365-1370 ◽  
Author(s):  
Augusta I. Kvam ◽  
Rooyen T. Mavenyengwa ◽  
Andreas Radtke ◽  
Johan A. Maeland
Keyword(s):  
Genomic Sequence ◽  
Cross Reactivity ◽  
Antigenic Determinants ◽  
Enzyme Linked Immunosorbent Assay ◽  
Group B Streptococci ◽  
Whole Cells ◽  
Repeat Units ◽  
The Alps ◽  
Antigenic Domains ◽  
Group B

ABSTRACTMost isolates of group B streptococci (GBS) express an alpha-like protein (Alp), Cα (encoded bybca), Alp1 (also called epsilon;alp1), Alp2 (alp2), Alp3 (alp3), Alp4 (alp4), or R4/Rib (rib). These proteins are chimeras with a mosaic structure and with antigenic determinants with variable immunological cross-reactivities between the Alps, including Alp1 and Cα cross-reactivity. This study focused on antigenic domains of Alp1, studied by using rabbit antisera in immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay (ELISA)-based tests and whole cells of GBS or trypsin-extracted and partially purified antigens from the strains A909 (serotype Ia/Cα, Cβ) and 335 (Ia/Alp1). Alp1 and Cα shared an antigenic determinant, Alp1/Cα common, not harbored by other Alps, probably located in the Alp1 and Cα repeat units, as these units are nearly identical in genomic sequence. An antigenic Alp1 determinant was Alp1 specific and was most likely located in the N-terminal unit of Alp1 in which an Alp1-specific primer site for PCR is also located. In addition, Alp1 possessed a domain with low immunogenicity which cross-reacted immunologically with Alp2 and Alp3, with unknown location in Alp1. Alp1 was partially degraded by trypsin during antigen extraction but with the antigenic domains preserved. The results indicate that Cα and Alp1 are immunologically related in the same manner that R4 (Rib) and Alp3 are related. The domain called Alp1 specific should be important in GBS serotyping as a surface-anchored serosubtype marker. The Alp1/Cα common determinant may be of prime interest as an immunogenic domain in a GBS vaccine.

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