1
|
Complete Genome Sequence of Serotype III Streptococcus agalactiae Sequence Type 17 Strain 874391. GENOME ANNOUNCEMENTS 2017; 5:5/42/e01107-17. [PMID: 29051249 PMCID: PMC5646402 DOI: 10.1128/genomea.01107-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here we report the complete genome sequence of Streptococcus agalactiae strain 874391. This serotype III isolate is a member of the hypervirulent sequence type 17 (ST-17) lineage that causes a disproportionate number of cases of invasive disease in humans and mammals. A brief historical context of the strain is discussed.
Collapse
|
2
|
Fléchard M, Gilot P. Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae. Microbiology (Reading) 2014; 160:1298-1315. [DOI: 10.1099/mic.0.077628-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB–lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the ‘success’ of the infectious process.
Collapse
Affiliation(s)
- Maud Fléchard
- Biochimie et Génétique Moléculaire Bactérienne, Institut des Sciences de la Vie, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Philippe Gilot
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France
- Université de Tours, UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, F-37032 Tours, France
| |
Collapse
|
3
|
Berner R. Significance, management and prevention of Streptococcus agalactiae infection during the perinatal period. Expert Rev Anti Infect Ther 2014; 2:427-37. [PMID: 15482207 DOI: 10.1586/14787210.2.3.427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The highest annual death rate during the first five decades of life occurs in the first year, particularly during the perinatal period between the onset of labor and 72 h after birth. Invasive bacterial disease evoking the severe inflammatory response syndrome is a leading cause of perinatal morbidity and mortality. Group B streptococcus (Streptococcus agalactiae) is the most important pathogen in this period of life, although the concept of intrapartum antimicrobial prophylaxis has impressively reduced the rate of culture-proven invasive infection in neonates. This strategy, however, has considerable limitations since group B streptococcus-related stillbirths or prematurity and late-onset sepsis cannot be prevented. Moreover, the use of intrapartum antimicrobial prophylaxis has significantly increased the use of antibiotics during labor and therefore may select for intrapartum infections caused by other bacteria, including those resistant to antibiotics. Several advances in the development of vaccines and research on virulence factors and pathways involved in the immune response to group B streptococcus have been accomplished within the last years, including complete sequencing of the group B streptococcus genome. Development of effective vaccines and implementation of vaccination strategies will be one of the key challenges in the future for prevention of neonatal group B Streptococcus infections.
Collapse
Affiliation(s)
- Reinhard Berner
- Department of Pediatrics and Adolescent Medicine, University Hospital Freiburg, Mathildenstrasse 1, D-79106 Freiburg, Germany.
| |
Collapse
|
4
|
Usein CR, Grigore L, Georgescu R, Cristea V, Bãltoiu M, Strãuţ M. Molecular characterization of adult-colonizing Streptococcus agalactiae from an area-based surveillance study in Romania. Eur J Clin Microbiol Infect Dis 2012; 31:2301-10. [DOI: 10.1007/s10096-012-1569-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/26/2012] [Indexed: 11/30/2022]
|
5
|
DiPersio LP, DiPersio JR, Beach JA, Loudon AM, Fuchs AM. Identification and characterization of plasmid-borne erm(T) macrolide resistance in group B and group A Streptococcus. Diagn Microbiol Infect Dis 2011; 71:217-23. [DOI: 10.1016/j.diagmicrobio.2011.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/22/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022]
|
6
|
Chattopadhyay D, Carey AJ, Caliot E, Webb RI, Layton JR, Wang Y, Bohnsack JF, Adderson EE, Ulett GC. Phylogenetic lineage and pilus protein Spb1/SAN1518 affect opsonin-independent phagocytosis and intracellular survival of Group B Streptococcus. Microbes Infect 2011; 13:369-382. [PMID: 21238599 PMCID: PMC4500112 DOI: 10.1016/j.micinf.2010.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 12/19/2010] [Accepted: 12/21/2010] [Indexed: 11/20/2022]
Abstract
Opsonin-independent phagocytosis of Group B Streptococcus (GBS) is important in defense against neonatal GBS infections. A recent study indicated a role for GBS pilus in macrophage phagocytosis (Maisey et al Faseb J 22 2008 1715-24). We studied 163 isolates from different phylogenetic backgrounds and those possessing or lacking the gene encoding the pilus backbone protein, Spb1 (SAN1518, PI-2b) and spb1-deficient mutants of wild-type (WT) serotype III-3 GBS 874391 in non-opsonic phagocytosis assays using J774A.1 macrophages. Numbers of GBS phagocytosed differed up to 23-fold depending on phylogenetic background; isolates possessing spb1 were phagocytosed more than isolates lacking spb1. Comparing WT GBS and isogenic spb1-deficient mutants showed WT was phagocytosed better compared to mutants; Spb1 also enhanced intracellular survival as mutants were killed more efficiently. Complementation of mutants restored phagocytosis and resistance to killing in J774A.1 macrophages. Spb1 antiserum revealed surface expression in WT GBS and spatial distribution relative to capsular polysaccharide. spb1 did not affect macrophage nitric oxide and TNF-alpha responses; differences in phagocytosis did not correlate with N-acetyl d-glucosamine (from GBS cell-wall) according to enzyme-linked lectin-sorbent assay. Together, these findings support a role for phylogenetic lineage and Spb1 in opsonin-independent phagocytosis and intracellular survival of GBS in J774A.1 macrophages.
Collapse
Affiliation(s)
- Debasish Chattopadhyay
- Department of Microbiology, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
| | - Alison J. Carey
- School of Medical Sciences and Griffith Health Institute, Griffith University, Gold Coast QLD Australia 4222
| | - Elise Caliot
- Unité de Biologie des Bactéries Pathogènes à Gram Positif, Institut Pasteur, 25-28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Richard I. Webb
- Centre for Microscopy and Microanalysis, University of Queensland, Australia 4072
| | - James R. Layton
- Department of Medicine, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
| | - Yan Wang
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis TN 38105
| | - John F. Bohnsack
- Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City UT 84136
| | - Elisabeth E. Adderson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis TN 38105
| | - Glen C. Ulett
- Department of Microbiology, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
- School of Medical Sciences and Griffith Health Institute, Griffith University, Gold Coast QLD Australia 4222
| |
Collapse
|
7
|
Epidemiology of and prenatal molecular distinction between invasive and colonizing group B streptococci in The Netherlands and Taiwan. Eur J Clin Microbiol Infect Dis 2009; 28:921-8. [PMID: 19333631 PMCID: PMC2723670 DOI: 10.1007/s10096-009-0726-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 02/23/2009] [Indexed: 11/01/2022]
Abstract
The identification of markers for virulent group B streptococci (GBS) could guide prenatal prevention and intervention strategies. We compared the distribution of serotypes and potential pathogenicity islands (PPIs) between invasive and colonizing GBS. Colonizing and invasive strains from The Netherlands and Taiwan were serotyped. We used polymerase chain reaction (PCR) for the amplification of several new PPI markers. Several combinations of PPI-specific markers and serotypes were associated with invasiveness. For Dutch neonatal strains, a receiver operating characteristic (ROC) curve with serotype and five PPI markers showed an area under the curve (AUC) of 0.963 (95% confidence interval [CI] 0.935-0.99). For Taiwanese neonatal strains, serotype and four different PPI markers resulted in an ROC curve with an AUC of 0.894 (95% CI 0.826-0.963). PPI-specific and serological markers can distinguish local neonatal invasive GBS strains from colonizing ones. Apparently, there are clear regional differences in the GBS epidemiology and infection potential of clones.
Collapse
|
8
|
Abstract
BACKGROUND Streptococcus agalactiae [group B streptococcus (GBS)] is a well-known cause of invasive infections leading to sepsis and meningitis in neonates. A comprehensive nationwide active surveillance study over 2 years was performed in Germany to describe the molecular epidemiology among 296 invasive neonatal GBS isolates. METHODS Isolates were typed by pulsed-field gel electrophoresis (PFGE). Typing results were compared with serotypes as well as to clinical data on disease onset, meningitic involvement, and outcome. RESULTS A remarkable clustering was found with about 60% of all typeable invasive isolates being annotated to one of 7 major PFGE groups, and clusters being nationally widely spread over the whole time period. Despite heterogenic elements, certain PFGE groups were closely related to singular serotypes, especially serotypes V (82%), Ia (84%), and Ib (77%). PFGE groups and serotypes were also partly related to clinical presentation as either early onset disease or late onset disease, and either meningitis or nonmeningitic GBS disease, but not to outcome. CONCLUSIONS There is a remarkable clonality among invasive GBS isolates that are widely spread geographically and in time; however, no specific clonal lines could be correlated to disease severity and outcome.
Collapse
|
9
|
Olivares-Fuster O, Klesius PH, Evans J, Arias CR. Molecular typing of Streptococcus agalactiae isolates from fish. JOURNAL OF FISH DISEASES 2008; 31:277-283. [PMID: 18353019 DOI: 10.1111/j.1365-2761.2007.00900.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The genetic variability among Streptococcus agalactiae isolates recovered from fish was characterized using single-stranded conformation polymorphism (SSCP) analysis of the intergenic spacer region (ISR), and amplified fragment length polymorphism (AFLP) fingerprinting. A total of 46 S. agalactiae cultures isolated from different fish species and geographic origins as well as related reference strains were included in the study. ISR-SSCP divided the S. agalactiae isolates analysed into five distinct genotypes. Genotype 1 grouped all Kuwait isolates while genotype 4 clustered the majority of non-Kuwait isolates (USA, Brazil and Honduras). AFLP analysis offered a higher resolution level by dividing the isolates into 13 different genotypes. Two different AFLP profiles were identified within the Kuwait isolates. When data from both ISR-SSCP and AFLP were combined through a multidimensional analysis (MDS), a good correlation between geographical origin and genotypes was observed. Both AFLP and ISR-SSCP revealed genetic differences between S. agalactiae isolates from fish. While AFLP offered a higher resolution, ISR-SSCP also provided valid information being a simpler and faster method.
Collapse
Affiliation(s)
- O Olivares-Fuster
- Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL 36849, USA
| | | | | | | |
Collapse
|
10
|
Zhao Z, Kong F, Zeng X, Gidding H, Morgan J, Gilbert G. Distribution of genotypes and antibiotic resistance genes among invasive Streptococcus agalactiae (group B streptococcus) isolates from Australasian patients belonging to different age groups. Clin Microbiol Infect 2008; 14:260-7. [DOI: 10.1111/j.1469-0691.2007.01914.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
11
|
Seifert KN, Adderson EE, Whiting AA, Bohnsack JF, Crowley PJ, Brady LJ. A unique serine-rich repeat protein (Srr-2) and novel surface antigen (epsilon) associated with a virulent lineage of serotype III Streptococcus agalactiae. MICROBIOLOGY-SGM 2006; 152:1029-1040. [PMID: 16549667 DOI: 10.1099/mic.0.28516-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
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, epsilon, was found to be co-expressed with the previously reported delta antigen on an identical subset of serotype III GBS. Expression of delta/epsilon 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. epsilon-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 delta/epsilon-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, delta/epsilon-negative serotype III and serotype V GBS strains. Representative serotype III delta/epsilon-positive strains had LD(90) values 3-4 logs less than those of serotype III delta/epsilon-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.
Collapse
Affiliation(s)
- Kyle N Seifert
- Department of Biology, James Madison University, Harrisonburg, VA 22807, USA
| | - Elisabeth E Adderson
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - April A Whiting
- Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
| | - John F Bohnsack
- Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
| | - Paula J Crowley
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
| | - L Jeannine Brady
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
| |
Collapse
|
12
|
Lindahl G, Stålhammar-Carlemalm M, Areschoug T. Surface proteins of Streptococcus agalactiae and related proteins in other bacterial pathogens. Clin Microbiol Rev 2005; 18:102-27. [PMID: 15653821 PMCID: PMC544178 DOI: 10.1128/cmr.18.1.102-127.2005] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Streptococcus agalactiae (group B Streptococcus) is the major cause of invasive bacterial disease, including meningitis, in the neonatal period. Although prophylactic measures have contributed to a substantial reduction in the number of infections, development of a vaccine remains an important goal. While much work in this field has focused on the S. agalactiae polysaccharide capsule, which is an important virulence factor that elicits protective immunity, surface proteins have received increasing attention as potential virulence factors and vaccine components. Here, we summarize current knowledge about S. agalactiae surface proteins, with emphasis on proteins that have been characterized immunochemically and/or elicit protective immunity in animal models. These surface proteins have been implicated in interactions with human epithelial cells, binding to extracellular matrix components, and/or evasion of host immunity. Of note, several S. agalactiae surface proteins are related to surface proteins identified in other bacterial pathogens, emphasizing the general interest of the S. agalactiae proteins. Because some S. agalactiae surface proteins elicit protective immunity, they hold promise as components in a vaccine based only on proteins or as carriers in polysaccharide conjugate vaccines.
Collapse
Affiliation(s)
- Gunnar Lindahl
- Department of Medical Microbiology, Dermatology and Infection, Lund University, Sölvegatan 23, SE-22362 Lund, Sweden.
| | | | | |
Collapse
|
13
|
Bröker G, Spellerberg B. Surface proteins of Streptococcus agalactiae and horizontal gene transfer. Int J Med Microbiol 2004; 294:169-75. [PMID: 15493827 DOI: 10.1016/j.ijmm.2004.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Streptococcus agalactiae is responsible for serious infectious diseases in neonates, immuno-compromised adult patients and causes bovine mastitis in animal hosts. Genome sequencing projects revealed strong indications for horizontal gene transfer events leading to virulence acquisition and genetic diversity in this species. Bacterial surface proteins establish the first contact with host tissues and represent interesting targets for the exchange of virulence properties among different streptococci. This review will focus on horizontal gene transfer events in characterized S. agalactiae surface proteins, mobile genetic elements adjacent to the corresponding genes and will discuss potential mechanisms of transfer.
Collapse
Affiliation(s)
- Gerd Bröker
- Department of Medical Microbiology and Hygiene, University of Ulm, Robert Koch Str 8, D-89081 Ulm, Germany
| | | |
Collapse
|
14
|
Fleming KE, Bohnsack JF, Palacios GC, Takahashi S, Adderson EE. Equivalence of high-virulence clonotypes of serotype III group B Streptococcus agalactiae (GBS). J Med Microbiol 2004; 53:505-508. [PMID: 15150329 DOI: 10.1099/jmm.0.05443-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Analysis of growth characteristics, multilocus enzyme electrophoresis, restriction digest pattern (RDP) typing and multilocus sequence typing have identified clonotypes of serotype III group B Streptococcus agalactiae (GBS) associated with invasive infection in neonates. This study sought to unify phenotypic and genotypic classifications of type III GBS strains associated with increased virulence in newborns. High-virulence clonotype (HVC) strains possessed the translation initiation factor 2 (infB) C allele, found in RDP type III-3 strains, and hybridized with the RDP type III-3-specific probe AA3.6, whereas non-HVC strains shared the infB A allele and genomic DNA from these strains did not hybridize with the AA3.6 probe. The characteristic growth lag of HVC GBS at 40 degrees C has been attributed to the presence of a heat-labile fructose-1,6-bisphosphate aldolase (Fba) enzyme in these strains. The deduced amino acid sequence of fba genes of both HVC and non-HVC strains, however, were identical. HVC and RDP type III-3 represent the same genetically related group of bacteria. The characteristic growth differences of virulent strains of type III GBS, however, are not directly attributable to differences in fba.
Collapse
Affiliation(s)
- Katherine E Fleming
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA 2Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA 3Instituto Mexicano del Seguro Social, Mexico City, Mexico 4Department of Microbiology, Joshi-Eiyoh University, Sakano, Japan
| | - John F Bohnsack
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA 2Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA 3Instituto Mexicano del Seguro Social, Mexico City, Mexico 4Department of Microbiology, Joshi-Eiyoh University, Sakano, Japan
| | - Geraldo C Palacios
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA 2Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA 3Instituto Mexicano del Seguro Social, Mexico City, Mexico 4Department of Microbiology, Joshi-Eiyoh University, Sakano, Japan
| | - Shinji Takahashi
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA 2Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA 3Instituto Mexicano del Seguro Social, Mexico City, Mexico 4Department of Microbiology, Joshi-Eiyoh University, Sakano, Japan
| | - Elisabeth E Adderson
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA 2Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA 3Instituto Mexicano del Seguro Social, Mexico City, Mexico 4Department of Microbiology, Joshi-Eiyoh University, Sakano, Japan
| |
Collapse
|
15
|
Adderson EE, Takahashi S, Wang Y, Armstrong J, Miller DV, Bohnsack JF. Subtractive hybridization identifies a novel predicted protein mediating epithelial cell invasion by virulent serotype III group B Streptococcus agalactiae. Infect Immun 2004; 71:6857-63. [PMID: 14638773 PMCID: PMC308952 DOI: 10.1128/iai.71.12.6857-6863.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group B Streptococcus agalactiae bacteria (group B streptococci [GBS]) are the most common cause of serious bacterial infection in newborn infants. The majority of serotype III-related cases of neonatal disease are caused by a genetically related subgroup of bacteria, restriction fragment digest pattern (RDP) type III-3, suggesting that these strains possess unique genes contributing to virulence. We used genomic subtractive hybridization to identify regions of genomic DNA unique to virulent RDP type III-3 GBS strains. Within one of these III-3-specific regions is a 1,506-bp open reading frame, spb1 (surface protein of group B streptococcus 1). A mutant type III GBS strain lacking Spb1 was constructed in virulent RDP type III-3 strain 874391, and the interactions of the wild-type and spb1 isogenic mutant with a variety of epithelial cells important to GBS colonization and infection were compared. While adherence of the spb1 isogenic mutant to A549 respiratory, C2Bbe1 colonic, and HeLa cervical epithelial cells was slightly lower than that of the 874391 strain, invasion of the Spb1(-) mutant was significantly reduced with these cell lines compared to what was seen with 874391. The defect in epithelial invasion was corrected by supplying spb1 in trans. These observations suggest that Spb1 contributes to the pathogenesis of neonatal GBS infection by mediating internalization of virulent serotype III GBS and confirm that understanding of the population structure of bacteria may lead to insights into the pathogenesis of human infections.
Collapse
Affiliation(s)
- Elisabeth E Adderson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
| | | | | | | | | | | |
Collapse
|
16
|
Luan SL, Granlund M, Norgren M. An inserted DNA fragment with plasmid features is uniquely associated with the presence of the GBSi1 group II intron in Streptococcus agalactiae. Gene 2003; 312:305-12. [PMID: 12909368 DOI: 10.1016/s0378-1119(03)00634-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The group II intron (GBSi1) identified downstream of the C5a-peptidase gene (scpB) in a subpopulation of Streptococcus agalactiae isolates is a suggested marker for a separate genetic lineage of serotype III isolates. In the present study two additional copies of GBSi1, one of which not previously described, were identified among serotype III isolates. All intron copies shared a common target site motif. A single copy of GBSi1 was found in a subgroup of serotype II and V isolates. In these isolates, the intron had inserted downstream of scpB, which suggests that this is the primary insertion site for GBSi1. Most bacterial group II introns described to date reside in transposable elements. The scpB locus was found to be flanked by insertion sequences similar to what has been described in an intronless serotype Ia isolate. However, this region contained an additional 2.1 kb DNA fragment present only in intron carrying isolates. This DNA fragment contained a partial transposase and putative plasmid related proteins. This may suggest that GBSi1 once was brought into the S. agalactiae genome by an integrated plasmid.
Collapse
Affiliation(s)
- Shi-Lu Luan
- Department of Biomedical Laboratory Science, Umeå University, S-901 87, Umeå, Sweden
| | | | | |
Collapse
|
17
|
Jones N, Bohnsack JF, Takahashi S, Oliver KA, Chan MS, Kunst F, Glaser P, Rusniok C, Crook DWM, Harding RM, Bisharat N, Spratt BG. Multilocus sequence typing system for group B streptococcus. J Clin Microbiol 2003; 41:2530-6. [PMID: 12791877 PMCID: PMC156480 DOI: 10.1128/jcm.41.6.2530-2536.2003] [Citation(s) in RCA: 448] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A multilocus sequence typing (MLST) system was developed for group B streptococcus (GBS). The system was used to characterize a collection (n = 152) of globally and ecologically diverse human strains of GBS that included representatives of capsular serotypes Ia, Ib, II, III, V, VI, and VIII. Fragments (459 to 519 bp) of seven housekeeping genes were amplified by PCR for each strain and sequenced. The combination of alleles at the seven loci provided an allelic profile or sequence type (ST) for each strain. A subset of the strains were characterized by restriction digest patterning, and these results were highly congruent with those obtained with MLST. There were 29 STs, but 66% of isolates were assigned to four major STs. ST-1 and ST-19 were significantly associated with asymptomatic carriage, whereas ST-23 included both carried and invasive strains. All 44 isolates of ST-17 were serotype III clones, and this ST appeared to define a homogeneous clone that was strongly associated with neonatal invasive infections. The finding that isolates with different capsular serotypes had the same ST suggests that recombination occurs at the capsular locus. A web site for GBS MLST was set up and can be accessed at http://sagalactiae.mlst.net. The GBS MLST system offers investigators a valuable typing tool that will promote further investigation of the population biology of this organism.
Collapse
Affiliation(s)
- Nicola Jones
- Nuffield Department of Clinical Laboratory Sciences, Institute for Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
von Both U, Ruess M, Mueller U, Fluegge K, Sander A, Berner R. A serotype V clone is predominant among erythromycin-resistant Streptococcus agalactiae isolates in a southwestern region of Germany. J Clin Microbiol 2003; 41:2166-9. [PMID: 12734270 PMCID: PMC154707 DOI: 10.1128/jcm.41.5.2166-2169.2003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One hundred ninety-three Streptococcus agalactiae isolates of neonatal origin and 146 isolates from adult women were analyzed for macrolide resistance and investigated for clonality. Among erythromycin-resistant isolates, serotype V turned out to be the most frequent. Comparative pulsed-field gel electrophoresis analysis revealed genetic clustering of resistant strains and predominance of a single clone family within an otherwise heterogeneous serotype V population.
Collapse
|
19
|
Abstract
Group B streptococcus (Streptococcus agalactiae) is still of great relevance in the perinatal period, although maternal antimicrobial prophylaxis has significantly reduced the rate of culture-confirmed invasive infection in neonates. This strategy, however, raises considerable concern because preterm delivery or late-onset sepsis cannot be prevented, and antibiotic resistance is increasing worldwide. Several advances in the development of conjugate vaccines and in research on virulence factors and pathways involved in the immune response to group B streptococcus have been accomplished, some of which might reach clinical practice in the near future.
Collapse
MESH Headings
- Antibodies, Bacterial/immunology
- Drug Resistance, Multiple, Bacterial
- Female
- Humans
- Infant, Newborn
- Infant, Premature, Diseases/drug therapy
- Infant, Premature, Diseases/epidemiology
- Infant, Premature, Diseases/microbiology
- Infant, Premature, Diseases/prevention & control
- Pregnancy
- Streptococcal Infections/drug therapy
- Streptococcal Infections/epidemiology
- Streptococcal Infections/immunology
- Streptococcal Infections/prevention & control
- Streptococcal Vaccines/immunology
- Streptococcus agalactiae/classification
- Streptococcus agalactiae/immunology
- Streptococcus agalactiae/pathogenicity
- Streptococcus agalactiae/physiology
- Virulence
Collapse
Affiliation(s)
- Reinhard Berner
- Department of Pediatrics, University Hospital Freiburg, Freiburg, Germany.
| |
Collapse
|