Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
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

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

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