Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.3.23 (GAS)
 957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of studies on throat carriage of beta hemolytic streptococci (BHS) carried out during the years 1972-90 in urban and rural school children from low socioeconomic groups in the age group of 5-15 years in and around Delhi showed an overall carriage rate of BHS varying from 12.2%-64.3% depending upon the season and number of swabs taken. Group A was found to be the most predominant serological group (31.1%-62.6%). The T-typability was found to be 98.2%. The most prevalent T-patterns observed during 1972-78 study were 3/13/B3264 followed by 5/11/12/27/44. A significant difference was observed in the prevalence of T-patterns during the study of 2,034 children from 1979-83 and 3,094 children from 1984-90. When the most prevalent T-patterns were found to be 5/11/12/27/44 followed by 3/13/B3264. The study of the school children from 1972-90 showed the isolation of BHS as well as significant predominance of GAS (p < 0.001) in winter months than summer months. There was no difference in the distribution of carriage of BHS and GAS amongst rural or urban school children. Since RF/RHD are illnesses which were often encountered in school children among socially and economically disadvantaged populations stronger support for streptococcal surveillance programs should be encouraged.
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PMID:Streptococcal throat carriage in school children with special reference to seasonal incidence. 129 77

We used an ELISA to determine the levels of specific anti-GAS carbohydrate IgG, IgM and IgA in 34 patients with acute rheumatic fever (ARF) with or without carditis, in 15 patients with acute glomerulonephritis (AGN) and in 18 control patients with noncomplicated GAS pharyngitis. Patients with ARF and AGN showed a significantly higher geometric mean titer as well as a higher frequency of elevated Ig of the IgG, IgM and IgA A-CHO class antibodies during the acute stage of this disease, when compared to controls. The IgM and IgA geometric means of the antibody were higher in ARF with carditis patients as compared to the non-carditis or AGN patients; however, the differences were not significant. In addition a lower frequency of antibody decline was observed in ARF with carditis patients who were seen in follow-up after a 1-year period, supporting previous observations of the persistence of this antibody in patients with rheumatic heart disease.
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PMID:Immunoglobulin isotype response to the group-A streptococcal carbohydrate in humans. 305 40

In the latter half of the 20th century, the clinical importance of variation in the virulence of strains of GAS has been clearly demonstrated. Although still obscure, the pathogenesis of ARF requires immunologically significant infection of the throat by virulent GAS strains. These strains contain large hyaluronate capsules and large M-protein molecules. The latter contain epitopes cross-reactive with host tissues, and also contain superantigenic toxic moieties. In areas where ARF has become rare, GAS pharyngitis continues to be common but is caused predominantly by GAS strains of relatively low virulence. These, however, may colonize the throat avidly and stubbornly. Molecularly distinct pyoderma strains may cause acute glomerulonephritis, but they are not rheumatogenic even though they may secondarily infect the throat. In developing countries with a very high incidence of rheumatic heart disease, identification of the prevalent rheumatogenic GAS strains and development of a multivalent vaccine against them is currently an interesting strategy. Pending vaccine development, intense primary and secondary penicillin prophylaxis should continue to be sharply focused on populations with the highest prevalence of RHD as such measures may often succeed in driving away the most virulent rheumatogenic clones of GAS from their midst.
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PMID:Can we eradicate rheumatic fever in the 21st century? 1142 92

Post-streptococcal sequelae, especially acute rheumatic fever/rheumatic heart disease continue to occur in significant proportions in many parts of the world. Despite several attempts with various intervention strategies, little success has been achieved in the control of acute rheumatic fever/rheumatic heart disease in India. The success of the control programmes depends upon timely primary prophylaxis with benzathine penicillin for which a microbiological confirmation of group A streptococcal pharyngitis is essential. Isolation of beta hemolytic streptococci from throat cultures and their identification as GAS in the laboratory, clinches the microbiological diagnosis while demonstration of a 'significant rise' in antibody titers such as Anti-streptolysin O and Anti-deoxyribonuclease B differentiates it from a group A streptococcal carrier state or pharyngitis of a viral etiology. Despite the easiness with which these can be achieved, many laboratories in India are not equipped to do so. Enhancing bacteriological and serological facilities in laboratories across the country will drastically improve the clinician's ability to diagnose bona fide GAS pharyngitis and help to institute penicillin prophylaxis at the appropriate time. This will go a long way in enhancing the compliance to penicillin prophylaxis which is the cornerstone of any RF/RHD control program.
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PMID:Microbiological diagnosis of streptococcal pharyngitis: lacunae and their implications. 1668 57

Rheumatic fever (RF) and rheumatic heart disease (RHD) are postinfectious complications of an infection (or repeated infection) with the Gram-positive bacterium, Streptococcus pyogenes (also known as group A streptococcus, GAS). RF and RHD are global problems and affect many indigenous populations of developed countries and many developing countries. However, RF and RHD are only part of a larger spectrum of diseases caused by this organism. The development of a vaccine against GAS has primarily targeted the abundant cell-surface protein called the M-protein. This review focuses on different M-protein-based-subunit vaccine approaches and the different delivery technologies used to administer these vaccine candidates in preclinical studies.
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PMID:Advances in potential M-protein peptide-based vaccines for preventing rheumatic fever and rheumatic heart disease. 1717 49

We now have a much more detailed understanding of the molecular pathogenesis of GAS infections. These discoveries have led to the identification of several vaccine candidates which are in various stages of development. One of the leading candidate antigens is the surface M protein, which confers protection against infection in animal models. In addition, M antibodies in human serum correlate with protection against infection with the homologous serotype of GAS. Molecular techniques have been used to genetically engineer highly complex multivalent M protein-based vaccines that appear to be free of potentially harmful tissue crossreactive epitopes. A 26-valent vaccine has been shown to be well-tolerated and immunogenic in adult volunteers and is now being considered for pediatric trials, which is the primary target group for the vaccine. Ongoing efforts are now addressing the epidemiology of GAS infections in developing countries so that new vaccines can be designed to prevent the infections that may trigger ARF and RHD. Successful deployment of safe and effective vaccines to prevent GAS infections and their complications could potentially have a significant impact on the health of millions of people around the world.
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PMID:Current status of group A streptococcal vaccine development. 1819 57

Rheumatic heart disease is the most severe complication of rheumatic fever. Till date, very few successful animal models of rheumatic valvular disease have been reported. This study aimed at developing a suitable animal model of chronic rheumatic valvulitis for further investigation and prevention of rheumatic heart disease. Lewis rats were immunized with one administration of formalin-killed and sonicated group A streptococci together with Complete Freund's Adjuvant every 7 days for three cycles followed by group A streptococci alone till killing. Control rats were administered adjuvants and saline. Rats in group 1 were killed 12 weeks after the initial injection. Rats in group 2 and control group were killed 24 weeks after the initial injection. Results 62.5% (5/8) of rats in group 1 developed myocarditis and 50% (4/8) developed valvulitis. Histological examination of cardiac sections showed only cellular infiltrates. In contrast, 75% (6/8) of rats in group 2 developed rheumatic-like myocarditis and 62.5% (5/8) developed chronic valvulitis. Histological manifestations of the hearts in group 2 animals involved not only acute damage such as cellular infiltrates, Aschoff-like cells, verrucous vegetation, but also chronic lesions such as fibrosis, vascular neogenesis. None of the rats (0/8) in control group presented myocarditis or valvulitis. Lewis rat repeatedly immunized with formalin-killed GAS may be a suitable animal model of chronic rheumatic valvulitis. It may be useful for future investigation of the pathogenesis and possible preventive strategies of human rheumatic heart disease.
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PMID:An animal model of chronic rheumatic valvulitis induced by formalin-killed streptococci. 2001 32

Diseases caused by Streptococcus pyogenes (Group A streptococcus, GAS) range from superficial infections such as pharyngitis and impetigo to potentially fatal rheumatic heart disease and invasive disease. Studies spanning emm-typing surveillance to population genomics are providing new insights into the epidemiology, pathogenesis, and biology of this organism. Such studies have demonstrated the differences that exist in the epidemiology of streptococcal disease between developing and developed nations. In developing nations, where streptococcal disease is endemic, the diversity of GAS emm-types circulating is much greater than that found in developed nations. An association between emm-type and disease, as observed in developed countries is also lacking. Intriguingly, comparative genetic studies suggest that emm-type is not always a good predictor of the evolutionary relatedness of geographically distant isolates. A view of GAS as a highly dynamic organism, in possession of a core set of virulence genes that contribute to host niche specialization and common pathogenic processes, augmented by accessory genes that change the relative virulence of specific lineages is emerging. Our inability to definitively identify genetic factors that contribute to specific disease outcome underscores the complex nature of streptococcal diseases.
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PMID:Molecular markers for the study of streptococcal epidemiology. 2317 74

The aim of this study is to determinate the prevalence of oropharyngeal colonization by group A beta-hemolytic Streptococcus (GABHS) in pediatric population of Ponta Grossa, a midsize city of southern Brazil; estimate the effectiveness of antistreptolysin-O (ASO), compared to culture, in presence of infection; and design an unpublished investigative algorithm of rheumatic fever's suspicion, based on needs identified in worldwide consensus. It is an epidemiologic, observational and transversal study, involving 180 children younger than 12 years. Secretion of posterior oropharynx was collected for culture; and peripheral blood for determination of ASO. Student-t and chi-square tests, with Yates correction, were performed for statistical analysis. The ASO cutoff was determined by Receiver Operating Characteristic (ROC) curve. The prevalence encountered was 3.9%, and 25.5% of the children showed reagent ASO. This serological test demonstrated quantitatively and qualitatively significant associations to the GABHS presence (p=0.0001 for both associations) throughout the ROC curve, 200 U Todd was the value that resulted in the best accuracy, demonstrating 100% of sensibility and 80% of specificity in the GAS infection documentation. Also, it was found that the value of 1.200 U represents a specificity of 100%. The results emphasize the need for similar studies in other populations, to provide better targeting of the diagnosis and treatment of oropharyngitis by GABHS, which in turn can prevent up to 80% the cases of rheumatic fever, and consequently, the chronic rheumatic heart disease.
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PMID:Prevalence of group a Beta-hemolytic streptococcus oropharyngeal colonization in children and therapeutic regimen based on antistreptolysin levels: data from a city from southern Brazil. 2513 88

Rheumatic heart disease (RHD) makes a heavy burden in human lives and economy. The proteomic analysis of acute rheumatic heart disease (ARHD) can provide precious data to study RHD at the early stages, but no one has looked into. So based on our early research we applied the method of continuous GAS stimulation on Lewis rats to duplicate the animal model of ARHD. And the mitral valves of rats in control group (n=10) and ARHD group (n=10) were selected for proteomic analysis of ARHD with the iTRAQ labeling based 2D LC-ESI-MS/MS quantitative technology. We identified 3931 proteins in valve tissue out of which we obtained 395 differentially expressed proteins containing 176 up-regulated proteins and 119 down-regulated proteins. Changes in levels of GAPDH (6.793 times higher than the control group) and CD9 (2.63 times higher than the control group) were confirmed by Western blot or immunohistochemistry. The differentially expressed proteins such as GAPDH, CD9, myosin, collagen and RAC1 may be potential biomarkers for ARHD. Moreover, the mitral valve protein profile shed light on further understanding and investigating ARHD.
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PMID:Proteomic analysis of mitral valve in Lewis rat with acute rheumatic heart disease. 2682 28


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