scholarly journals Virulence factors in streptococcal infective endocarditis

2005 ◽  
Vol 26 (3) ◽  
pp. 114
Author(s):  
Derek W S Harty
Keyword(s):  
Infective Endocarditis ◽  
Heart Valves ◽  
Blood Stream ◽  
Mutans Streptococci ◽  
Oral Streptococci ◽  
Streptococcus Anginosus ◽  
Streptococcus Oralis ◽  
Causative Agents ◽  
Life Threatening ◽  
Micro Organisms

Infective endocarditis (IE) is a life threatening, endovascular infection occurring when bacteria enter the blood stream and adhere to heart valves. Mortality rates remain in the range of 11-27%. The most common infecting micro-organisms are now the staphylococci (44%) although streptococci (31%) and particularly the oral streptococci (21%) are still major causative agents. Many different oral streptococci have been isolated from IE cases, the most common being Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, Streptococcus mitis, Streptococcus anginosus group and mutans streptococci.

scholarly journals A novel sialic acid-binding adhesin present in multiple species contributes to the pathogenesis of Infective endocarditis

2020 ◽  
Author(s):  
Meztlli O. Gaytán ◽  
Anirudh K. Singh ◽  
Shireen A. Woodiga ◽  
Surina A. Patel ◽  
Seon-Sook An ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Infective Endocarditis ◽  
Therapeutic Target ◽  
Heart Valves ◽  
Bacterial Species ◽  
Rabbit Model ◽  
Host Factors ◽  
Dependent Manner ◽  
Streptococcus Oralis ◽  
Sialic Acid Binding

AbstractBacterial binding to platelets is a key step in the development of infective endocarditis (IE). Sialic acid, a common terminal carbohydrate on host glycans, is the major receptor for streptococci on platelets. So far, all defined interactions between streptococci and sialic acid on platelets are mediated by serine rich repeat proteins (SRRPs). However, we identified Streptococcus oralis subsp. oralis IE-isolates that bind sialic acid but lack SRRPs. In addition to binding sialic acid, some SRRP-negative isolates also bind the cryptic receptor β-1,4-linked galactose through a yet unknown mechanism. Using comparative genomics, we identified a novel sialic acid-binding adhesin, here named AsaA (associated with sialic acid adhesion A), present in IE-isolates lacking SRRPs. We demonstrated that S. oralis subsp. oralis AsaA is required for binding to platelets in a sialic acid-dependent manner. AsaA comprises a non-repeat region (NRR), consisting of a FIVAR/CBM and two Siglec-like and Unique domains, followed by 31 DUF1542 domains. When recombinantly expressed, Siglec-like and Unique domains competitively inhibited binding of S. oralis subsp. oralis and directly interacted with sialic acid on platelets. We further demonstrated that AsaA impacts the pathogenesis of S. oralis subsp. oralis in a rabbit model of IE. Additionally, we found AsaA orthologues in other IE-causing species and demonstrated that the NRR of AsaA from Gemella haemolysans blocked binding of S. oralis subsp. oralis, suggesting that AsaA contributes to the pathogenesis of multiple IE-causing species. Finally, our findings provide evidence that sialic acid is a key factor for bacterial-platelets interactions in a broader range of species than previously appreciated, highlighting its potential as a therapeutic target.Authors summaryInfective endocarditis (IE) is typically a bacterial infection of the heart valves that causes high mortality. Infective endocarditis can affect people with preexisting lesions on their heart valves (Subacute-IE). These lesions contain platelets and other host factors to which bacteria can bind. Growth of bacteria and accumulation of host factors results in heart failure. Therefore, the ability of bacteria to bind platelets is key to the development of IE. Here, we identified a novel bacterial protein, AsaA, which helps bacteria bind to platelets and contributes to the development of disease. Although this virulence factor was characterized in Streptococcus oralis, a leading cause of IE, we demonstrated that AsaA is also present in several other IE-causing bacterial species and is likely relevant to their ability to cause disease. We showed that AsaA binds to sialic acid, a terminal sugar present on platelets, thereby demonstrating that sialic acid serves as a receptor for a wider range of IE-causing bacteria than previously appreciated, highlighting its potential as a therapeutic target.

scholarly journals Dental Caries Vaccines: Prospects and Concerns

2002 ◽  
Vol 13 (4) ◽  
pp. 335-349 ◽  
Author(s):  
D.J. Smith
Keyword(s):  
Dental Caries ◽  
Gingival Crevicular Fluid ◽  
Mutans Streptococci ◽  
Intact Protein ◽  
Oral Streptococci ◽  
Host Defenses ◽  
Dental Biofilm ◽  
History Of ◽  
Crevicular Fluid ◽  
Micro Organisms

Dental caries remains one of the most common infectious diseases of mankind. Cariogenic micro-organisms enter the dental biofilm early in life and can subsequently emerge, under favorable environmental conditions, to cause disease. In oral fluids, adaptive host defenses aroused by these infections are expressed in the saliva and gingival crevicular fluid. This review will focus on methods by which mucosal host defenses can be induced by immunization to interfere with dental caries caused by mutans streptococci. The natural history of mutans streptococcal colonization is described in the context of the ontogeny of mucosal immunity to these and other indigenous oral streptococci. Molecular targets for dental caries vaccines are explored for their effectiveness in intact protein and subunit (synthetic peptide, recombinant and conjugate) vaccines in pre-clinical studies. Recent progress in the development of mucosal adjuvants and viable and non-viable delivery systems for dental caries vaccines is described. Finally, the results of clinical trials are reviewed, followed by a discussion of the prospects and concerns of human application of the principles presented.

scholarly journals Prevalence of the Amylase-Binding Protein A Gene (abpA) in Oral Streptococci

1999 ◽  
Vol 37 (12) ◽  
pp. 4081-4085 ◽  
Author(s):  
Alan E. Brown ◽  
Jeffrey D. Rogers ◽  
Elaine M. Haase ◽  
Peter M. Zelasko ◽  
Frank A. Scannapieco
Keyword(s):  
Southern Blot ◽  
Genomic Dna ◽  
Binding Protein ◽  
Protein A ◽  
Oral Streptococci ◽  
Streptococcus Anginosus ◽  
Streptococcus Oralis ◽  
Genes Encoding ◽  
Pcr Products ◽  
Streptococcal Species

Salivary amylase binds specifically to a number of oral streptococcal species. This interaction may play an important role in dental plaque formation. Recently, a 585-bp gene was cloned and sequenced from Streptococcus gordonii Challis encoding a 20.5-kDa amylase-binding protein (AbpA). The goal of this study was to determine if related genes are present in other species of oral streptococci. Biotinylated abpA was used in Southern blot analysis to screen genomic DNA from several strains representing eight species of oral streptococci. This probe hybridized with a 4.0-kbHindIII restriction fragment from all 13 strains ofS. gordonii tested. The probe did not appear to bind to any restriction fragments from other species of amylase-binding oral streptococci including Streptococcus mitis (with the exception of 1 of 14 strains), Streptococcus crista (3 strains), Streptococcus anginosus (1 strain), andStreptococcus parasanguinis (1 strain), or to non-amylase-binding oral streptococci including Streptococcus sanguinis (3 strains), Streptococcus oralis (4 strains), and Streptococcus mutans (1 strain). Primers homologous to sequences within the 3′ and 5′ ends of abpAyielded products of 400 bp following PCR of genomic DNA from the Southern blot-positive strains. Several of these PCR products were cloned and sequenced. The levels of similarity of these cloned products to the abpA of S. gordonii Challis ranged from 91 to 96%. These studies reveal that the abpA gene appears to be specific to S. gordonii and differs from genes encoding amylase-binding proteins from other species of amylase-binding streptococci.

Infective endocarditis: Importance of molecular biological techniques in etiological diagnosis

2016 ◽  
Vol 88 (11) ◽  
pp. 62-67 ◽  
Author(s):  
E O Kotova ◽  
E A Domonova ◽  
Yu L Karaulova ◽  
A S Milto ◽  
A S Pisaryuk ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Heart Valves ◽  
Venous Blood ◽  
Bacteriological Examination ◽  
Etiological Diagnosis ◽  
Causative Agents ◽  
Pathogen Dna ◽  
Dna Pcr ◽  
Culture Negative ◽  
Molecular Biological Techniques

Aim. To investigate the specific features of conventional bacteriological methods and current molecular biological techniques for the etiological diagnosis of infective endocarditis (IE). Subjects and methods. Examinations were made in 53 patients treated at City Clinical Hospital Sixty-Four, Moscow Healthcare Department, in 2012—2015 who underwent simultaneous bacteriological and molecular biological (polymerase chain reaction (PCR) or PCR with further sequencing) examinations of blood or resected cardiac valve tissues. Results. The investigation included 53 patients (31 men; median age, 62 years) with IE (Duke 2009); its primary form was observed in 32 (60.4%) patients. Blood bacteriological tests and PCR assays were positive in 28 (52.8%) and 34 (64.2%) patients, respectively. There were concordant results in 21 of the 28 positive blood culture cases and discordant results in 7 (25%); at the same time 3 cases showed a compete discordance in the detected causative agents (the growth of Enterococcus spp. was revealed by bacteriological examination and that of Staphylococcus spp., Streptococcus spp., and Escherichia coli by DNA PCR) and a pathogen could not be identified by DNA PCR in 4 patients who had positive blood bacteriological results. The positive PCR results for cocci and fungi were obtained in 10 of the 25 (47.2%) examinees with culture-negative IE. Rare causative agents were not revealed. The tissues obtained from 8 resected damaged heart valves displayed a wider spectrum of pathogens than did blood samples, which was associated with the formation of bacterial films. Conclusion. The etiological agent of IE was revealed in venous blood by bacteriological examination in 52.8% of the examinees, by PCR in 64.2%, and by either in 71.7%. There were concordant and discordant results in 67.9 and 32.1% of the patients, respectively; among whom 18.9% were found to have pathogen DNA revealed by PCR in culture-negative IE.

scholarly journals Achromobacterspecies endocarditis: A Case Report and Literature Review

2011 ◽  
Vol 22 (3) ◽  
pp. e17-e20 ◽  
Author(s):  
Catherine Derber ◽  
Kara Elam ◽  
Betty A. Forbes ◽  
Gonzalo Bearman
Keyword(s):  
Infective Endocarditis ◽  
Literature Review ◽  
Heart Valves ◽  
Pulmonary Valve ◽  
Present Report ◽  
Achromobacter Xylosoxidans ◽  
Prosthetic Heart Valves ◽  
Life Threatening ◽  
High Degree ◽  
Prolonged Antibiotic Therapy

Endocarditis due toAchromobacterspecies is a rare, yet serious, endovascular infection.Achromobacterspecies infective endocarditis is associated with underlying immunodeficiencies or prosthetic heart valves and devices. A case of prosthetic pulmonary valve endocarditis secondary toAchromobacter xylosoxidanssubspeciesdenitrificansis described in the present report. This life-threatening infection was successfully treated with combined valve replacement and prolonged antibiotic therapy. A Medline/PubMed literature review ofAchromobacterendocarditis was also performed.Achromobacterspecies are an uncommon, yet important, cause of nosocomial endocarditis. Given the significant associated morbidity and mortality, along with a high degree of intrinsic antibiotic resistance,Achromobacterspecies infective endocarditis remains a clinical treatment challenge.

scholarly journals Bacteriæmia and Oral Sepsis

1939 ◽  
Vol 32 (7) ◽  
pp. 747-754 ◽  
Author(s):  
S. D. Elliott
Keyword(s):  
Infective Endocarditis ◽  
Inflammatory Reaction ◽  
Heart Valves ◽  
Blood Stream ◽  
Operative Procedures ◽  
Preliminary Treatment ◽  
Complete Elimination ◽  
Two Factors ◽  
Focus Of Infection

Transient streptococcal bacteriæmias are a frequent sequel to dental extractions especially when the mouth is the seat of severe chronic gum infection. Bacteria may also gain admission to the blood-stream in such cases irrespective of operative procedures and probably as the result, in many instances, of minor degrees of gum injury such as is produced by biting on a loose tooth. Acute apical infections do not appear to be especially associated with blood infection of this kind, the focus of infection here apparently being effectively “walled off” by the associated inflammatory reaction.Of the two factors, infection and trauma, involved in the production of these post-operative bacteriæmias, infection appears to be the more important since, when it is marked, very slight degrees of gum injury are sufficient to produce blood-stream invasion. In the complete absence, however, of the type of trauma induced by the “rocking” of a tooth during its removal, extraction may be accomplished without producing a heavy bacterial shower in the blood.Usually these transient bacteriæmias produce no permanent ill-effect, but there is some evidence that, occurring in subjects with abnormal heart valves, they may lead to subacute infective endocarditis. Thirteen cases are reported where the valvular infection appeared to result from a post-operative dental bacteriæmia.Prevention of such bacteriæmias may be achieved by the reduction or elimination of infection and trauma. Complete elimination of the gum infection is difficult although preliminary treatment of the gum margin by some measure such as cauterization may lessen it and lead to a reduction of the post-operative bacterial shower. Similarly, by manipulating an infected tooth as little as possible during its extraction the incidence or degree of blood infection may be decreased.

The Use of High - Sucrose Culture Media for the Identification of Oral Streptococci in Infant- Mother Pairs

2017 ◽  
Vol 68 (11) ◽  
pp. 2691-2693
Author(s):  
Krisztina Martha ◽  
Cristina Bica ◽  
Edva Anna Frunda
Keyword(s):  
Culture Media ◽  
Bacterial Flora ◽  
Mutans Streptococci ◽  
Resistant Bacteria ◽  
Oral Streptococci ◽  
Streptococcus Sobrinus ◽  
Sugar Intake ◽  
Tooth Surfaces ◽  
Refined Carbohydrates ◽  
High Sucrose

By the end of the 60�s, the theory that refined carbohydrates promotes the absorption of saccharolytic Gram-positive microbial species on the tooth surfaces has become generally. Mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) were key players in this theory. On agar plates, Str. mutans produces small, circular colonies, in the presence of glucose, and in the presence of sucrose large, sticky, gelatinous colonies. This gelatinous texture is due to the shell material: mutant 1 � 3 glucose polymers and dextran 1 �! 6 glucose polymers. Str. mutans are able to survive in the oral cavity with a pH lower than 5.5. That is why consecutive multiple sugar intake promotes the colonization of Str. mutans, which results in dental caries in stagnant zones. As oral pH is continuously shifted to acid, more acid-resistant bacteria appear. Our aim was to identify species in infant-mother pair gingival crevicular bacterial flora, which can be detected on high-sucrose culture media and to underline the jeopardy of vertical oral contamination from mother to infant.

Cross-sectional Analysis of Serum Antibody to Oral Streptococcal Antigens in Children

1988 ◽  
Vol 67 (3) ◽  
pp. 554-560 ◽  
Author(s):  
Z. Luo ◽  
D.J. Smith ◽  
M.A. Taubman ◽  
W.F. King
Keyword(s):  
Bacterial Colonization ◽  
Serum Antibody ◽  
Age Groups ◽  
Mutans Streptococci ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Activity ◽  
Igg Antibody ◽  
Cross Sectional ◽  
Streptococcal Species ◽  
Micro Organisms

Antibodies to S. salivarius, S. sanguis, and S. mutans cells and to glucosyltransferases (GTF) prepared from these micro-organisms were measured in the sera of 133 infants and children by enzyme-linked immunosorbent assay (ELISA). IgG antibody activity to each cell type and GTF was present at birth (presumably derived from maternal transfer) and declined significantly thereafter. IgG antibody levels to S. salivarius and S. sanguis were next detected in young children (2 to < 3 yr group). However, an increase in IgG antibody to S. mutans cells was not seen until children were older ( 4 to < 8 yr group), possibly reflecting the later colonization of this organism. In contrast, IgG antibody to GTF of all three streptococcal species remained at low levels throughout the first four years of life. IgG antibody to S. mutans GTF was then the first to appear ( 4 to < 8 yr group). Serum IgA antibodies to all GTFs were not detected until after this time. Fifteen sera were used to develop IgG immunoblots with the GTF antigens. Some positive sera (7/12) demonstrated reaction(s) with GTF from each of the three streptococcal species. Individual sera showed IgG antibody bands to GTF from several serotypes of the mutans streptococci. No immunoblot reaction was observed with GTF and sera (3) from the four-to-seven-year and younger age groups. These results indicate the presence of serum antibody to bacteria and bacterial products associated with plaque formation very early in life and during and after the pre-adolescent years. The potential exists for this serum antibody to modulate bacterial colonization or accumulation in the oral cavity.

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