RESUMO
BACKGROUND: Acute rheumatic fever remains a serious healthcare concern for the majority of the world's population despite its decline in incidence in Europe and North America. The goal of this statement was to review the historic Jones criteria used to diagnose acute rheumatic fever in the context of the current epidemiology of the disease and to update those criteria to also take into account recent evidence supporting the use of Doppler echocardiography in the diagnosis of carditis as a major manifestation of acute rheumatic fever. METHODS AND RESULTS: To achieve this goal, the American Heart Association's Council on Cardiovascular Disease in the Young and its Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee organized a writing group to comprehensively review and evaluate the impact of population-specific differences in acute rheumatic fever presentation and changes in presentation that can result from the now worldwide availability of nonsteroidal anti-inflammatory drugs. In addition, a methodological assessment of the numerous published studies that support the use of Doppler echocardiography as a means to diagnose cardiac involvement in acute rheumatic fever, even when overt clinical findings are not apparent, was undertaken to determine the evidence basis for defining subclinical carditis and including it as a major criterion of the Jones criteria. This effort has resulted in the first substantial revision to the Jones criteria by the American Heart Association since 1992 and the first application of the Classification of Recommendations and Levels of Evidence categories developed by the American College of Cardiology/American Heart Association to the Jones criteria. CONCLUSIONS: This revision of the Jones criteria now brings them into closer alignment with other international guidelines for the diagnosis of acute rheumatic fever by defining high-risk populations, recognizing variability in clinical presentation in these high-risk populations, and including Doppler echocardiography as a tool to diagnose cardiac involvement.
Assuntos
Ecocardiografia Doppler , Febre Reumática/diagnóstico por imagem , Doença Aguda , American Heart Association , Artrite Reativa/etiologia , Coreia/etiologia , Diagnóstico Diferencial , Saúde Global , Doenças das Valvas Cardíacas/diagnóstico por imagem , Doenças das Valvas Cardíacas/epidemiologia , Humanos , Miocardite/diagnóstico por imagem , Miocardite/epidemiologia , Recidiva , Febre Reumática/diagnóstico , Febre Reumática/epidemiologia , Cardiopatia Reumática/diagnóstico por imagem , Cardiopatia Reumática/epidemiologia , Risco , Infecções Estreptocócicas/complicações , Infecções Estreptocócicas/diagnóstico , Avaliação de Sintomas , Estados Unidos , Populações VulneráveisRESUMO
Serum penicillin G falls to low levels 2 weeks after injection as benzathine penicillin G (BPG) in young adults. Using Pmetrics and previously reported penicillin G pharmacokinetic data after 1.2 million units were given as BPG to 329 male military recruits, here we develop the first reported population pharmacokinetic model of penicillin G after BPG injection. We simulated time-concentration profiles over a broad range of pediatric and adult weights after alternative doses and dose frequencies to predict the probability of maintaining serum penicillin G concentrations of >0.02 mg/liter, a proposed protective threshold against group A Streptococcus pyogenes (GAS). The final population model included linear absorption into a central compartment, distribution to and from a peripheral compartment, and linear elimination from the central compartment, with allometrically scaled volumes and rate constants. With 1.2 million units of BPG given intramuscularly every 4 weeks in four total doses, only 23.2% of 5,000 simulated patients maintained serum penicillin G trough concentrations of >0.02 mg/liter 4 weeks after the last dose. When the doses were 1.8 million units and 2.4 million units, the percentages were 30.2% and 40.7%, respectively. With repeated dosing of 1.2 million units every 3 weeks and every 2 weeks for 4 doses, the percentages of simulated patients with a penicillin G trough concentration of >0.02 mg/liter were 37.8% and 65.2%, respectively. Our simulations support recommendations for more frequent rather than higher BPG doses to prevent recurrent rheumatic heart disease in areas of high GAS prevalence or during outbreaks.
Assuntos
Antibacterianos/farmacocinética , Penicilina G Benzatina/farmacocinética , Streptococcus pyogenes/efeitos dos fármacos , Adolescente , Adulto , Antibacterianos/sangue , Antibacterianos/metabolismo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Penicilina G Benzatina/sangue , Penicilina G Benzatina/metabolismo , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/microbiologia , Cardiopatia Reumática/microbiologia , Cardiopatia Reumática/prevenção & controle , Sífilis/tratamento farmacológico , Sífilis/microbiologia , Adulto JovemRESUMO
Group A streptococcal (Streptococcus pyogenes) infections remain important causes of medical and public health morbidity and mortality even during the early twenty-first century. Although most often concentrated in socially/economically disadvantaged populations, the problems remain significant in both industrializing and industrialized countries. The many M/emm types of GAS contribute to herd immunity in populations and also affect the control of streptococcal infections in these populations. Although this bacterium remains among the most susceptible to most antibiotics, it is evident that antibiotics alone have not solved the group A streptococcal medical and public health problems, even in those places where access to medical care is readily available. It is likely that the current streptococcal problems will remain difficult to manage and will remain essentially unchanged until the broad implementation of a cost-effective group A streptococcal vaccine, likely some years in the future.
Assuntos
Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes , Antibacterianos/uso terapêutico , Portador Sadio , Humanos , Saúde Pública , Sistema Respiratório/microbiologia , Infecções Estreptocócicas/epidemiologiaRESUMO
The past 50 years has witnessed the emergence of new viral and bacterial pathogens with global effect on human health. The hyperinvasive group A Streptococcus (GAS) M1T1 clone, first detected in the mid-1980s in the United States, has since disseminated worldwide and remains a major cause of severe invasive human infections. Although much is understood regarding the capacity of this pathogen to cause disease, much less is known of the precise evolutionary events selecting for its emergence. We used high-throughput technologies to sequence a World Health Organization strain collection of serotype M1 GAS and reconstructed its phylogeny based on the analysis of core genome single-nucleotide polymorphisms. We demonstrate that acquisition of a 36-kb genome segment from serotype M12 GAS and the bacteriophage-encoded DNase Sda1 led to increased virulence of the M1T1 precursor and occurred relatively early in the molecular evolutionary history of this strain. The more recent acquisition of the phage-encoded superantigen SpeA is likely to have provided selection advantage for the global dissemination of the M1T1 clone. This study provides an exemplar for the evolution and emergence of virulent clones from microbial populations existing commensally or causing only superficial infection.
Assuntos
Evolução Biológica , Pandemias , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/metabolismo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Linhagem Celular , Modelos Animais de Doenças , Células Epiteliais/microbiologia , Exotoxinas/genética , Exotoxinas/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Genoma Bacteriano , Saúde Global , Interações Hospedeiro-Patógeno , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Neutrófilos/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos , Fagocitose , Filogenia , Streptococcus pyogenes/classificação , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidade , Transcriptoma , VirulênciaRESUMO
The guideline is intended for use by healthcare providers who care for adult and pediatric patients with group A streptococcal pharyngitis. The guideline updates the 2002 Infectious Diseases Society of America guideline and discusses diagnosis and management, and recommendations are provided regarding antibiotic choices and dosing. Penicillin or amoxicillin remain the treatments of choice, and recommendations are made for the penicillin-allergic patient, which now include clindamycin.
Assuntos
Antibacterianos/uso terapêutico , Faringite/diagnóstico , Faringite/tratamento farmacológico , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes/isolamento & purificação , Adulto , Analgésicos não Narcóticos/uso terapêutico , Portador Sadio , Criança , Pré-Escolar , Humanos , Lactente , Estados UnidosRESUMO
The guideline is intended for use by healthcare providers who care for adult and pediatric patients with group A streptococcal pharyngitis. The guideline updates the 2002 Infectious Diseases Society of America guideline and discusses diagnosis and management, and recommendations are provided regarding antibiotic choices and dosing. Penicillin or amoxicillin remain the treatments of choice, and recommendations are made for the penicillin-allergic patient, which now include clindamycin.
Assuntos
Antibacterianos/uso terapêutico , Faringite/diagnóstico , Faringite/tratamento farmacológico , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes/isolamento & purificação , Adolescente , Adulto , Analgésicos não Narcóticos/uso terapêutico , Portador Sadio/diagnóstico , Portador Sadio/tratamento farmacológico , Portador Sadio/microbiologia , Criança , Pré-Escolar , Diagnóstico Diferencial , Humanos , Lactente , Faringite/microbiologia , Faringe/microbiologia , Infecções Estreptocócicas/microbiologia , Estados UnidosRESUMO
Between 1554 and 2021, the number of and mortality from epidemics in Amsterdam decreased sharply. The decrease in epidemic outbreaks, such as those of plague, smallpox and cholera, paralleled the decrease in chronic mortality from endemic ailments and diseases, such as tuberculosis, malaria and dysentery. There are several theories about the reason for these declines, which are not necessarily mutually exclusive: better nutrition, greater prosperity, increasing altruism, and a growing understanding of cause and effect with targeted medical and public health measures. In the powder keg of chronic poverty and poor public health, a social crisis, such as war, migration, and natural disaster, usually was the spark that led to epidemic outbreaks. The nature and extent of poverty and ill health have changed and improved over the centuries, but the threat of man-made crises is unfortunately unabated.
Assuntos
Cólera , Epidemias , Peste , Varíola , Cólera/epidemiologia , Surtos de Doenças , Humanos , Peste/epidemiologiaRESUMO
BACKGROUND: Determination of an immune response to group A Streptococcus (GAS) antigens, frequently anti-streptolysin O and anti-DNase B, is crucial for documentation of bona fide GAS infection. Although the importance of immunologic confirmation of infection is widely accepted, the immediate and long-term immunokinetics of the human antibody response are incompletely documented and poorly understood. METHODS: Pediatric study participants (n = 160) were followed during a 2-year study with monthly throat cultures (n = 3491) and blood samples (n = 1679) obtained every 13 weeks. Recovered GAS were characterized; serum anti-streptolysin O and anti-DNase B antibody titers were determined. Antibody titers and GAS culture results were temporally correlated and analyzed. RESULTS: The analyses clearly document, in some instances for the first time, that an increase in antibody titer more accurately defines infection than does an absolute titer (eg, "upper limit of normal"), that antibody titers can remain elevated for many months even without GAS, and that some individuals may harbor GAS continuously for months or years without symptoms of infection and without an associated immune response. Measuring 2 different antibodies is more accurate in defining infection. CONCLUSIONS: Single time-point cultures and single antibody titers are often misleading. Sequential samples more accurately define infection, allowing correlation of titer increases with temporal confirmation of GAS acquisition. Understanding kinetics of the immune response(s) to GAS infection is necessary in formulating accurate clinical diagnostic conclusions, to appropriate design of clinical and epidemiological studies examining the association of GAS with subsequent sequelae, and to providing insight into pathogenetic mechanisms associated with this important human pathogen.
Assuntos
Antígenos de Bactérias/imunologia , Infecções Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Adolescente , Antibacterianos/uso terapêutico , Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Estudos de Casos e Controles , Criança , Desoxirribonucleases/imunologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Faringe/microbiologia , Estudos Prospectivos , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/microbiologia , Estreptolisinas/imunologiaRESUMO
BACKGROUND & AIMS: The historical prevalence and long-term outcome of undiagnosed celiac disease (CD) are unknown. We investigated the long-term outcome of undiagnosed CD and whether the prevalence of undiagnosed CD has changed during the past 50 years. METHODS: This study included 9133 healthy young adults at Warren Air Force Base (sera were collected between 1948 and 1954) and 12,768 gender-matched subjects from 2 recent cohorts from Olmsted County, Minnesota, with either similar years of birth (n = 5558) or age at sampling (n = 7210) to that of the Air Force cohort. Sera were tested for tissue transglutaminase and, if abnormal, for endomysial antibodies. Survival was measured during a follow-up period of 45 years in the Air Force cohort. The prevalence of undiagnosed CD between the Air Force cohort and recent cohorts was compared. RESULTS: Of 9133 persons from the Air Force cohort, 14 (0.2%) had undiagnosed CD. In this cohort, during 45 years of follow-up, all-cause mortality was greater in persons with undiagnosed CD than among those who were seronegative (hazard ratio = 3.9; 95% confidence interval, 2.0-7.5; P < .001). Undiagnosed CD was found in 68 (0.9%) persons with similar age at sampling and 46 (0.8%) persons with similar years of birth. The rate of undiagnosed CD was 4.5-fold and 4-fold greater in the recent cohorts, respectively, than in the Air Force cohort (both P < or = .0001). CONCLUSIONS: During 45 years of follow-up, undiagnosed CD was associated with a nearly 4-fold increased risk of death. The prevalence of undiagnosed CD seems to have increased dramatically in the United States during the past 50 years.
Assuntos
Doença Celíaca/epidemiologia , Adolescente , Adulto , Idoso , Autoanticorpos/sangue , Doença Celíaca/diagnóstico , Doença Celíaca/imunologia , Doença Celíaca/mortalidade , Estudos de Coortes , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Militares , Prevalência , Prognóstico , Modelos de Riscos Proporcionais , Medição de Risco , Fatores de Tempo , Transglutaminases/imunologia , Estados Unidos/epidemiologia , Adulto JovemRESUMO
Group A streptococcal M type--specific protective antibodies-especially their persistence in humans--are incompletely understood. Such information is essential for understanding the epidemiology and pathogenesis of these infections and their sequelae and is equally crucial for producing a group A streptococcal vaccine. We studied 2 adults for type-specific antibody 45 years after they experienced documented rheumatic fever.
Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Transporte/imunologia , Febre Reumática/imunologia , Streptococcus pyogenes/imunologia , Humanos , Pessoa de Meia-Idade , Fatores de TempoRESUMO
A prospective, school-based study included daily monitoring for incidence of symptomatic streptococcal-associated pharyngitis and monthly determinations of group A streptococcal prevalence. A treatment group received penicillin/erythromycin therapy at school for positive throat cultures; the control group sought medical care from their regular provider. Prevalence and incidence of group A streptococcal pharyngitis were significantly lower among the treatment group than in the controls.
Assuntos
Antibacterianos/uso terapêutico , Faringite/prevenção & controle , Avaliação de Programas e Projetos de Saúde , Instituições Acadêmicas , Infecções Estreptocócicas/prevenção & controle , Streptococcus pyogenes/efeitos dos fármacos , Antibacterianos/administração & dosagem , Portador Sadio/tratamento farmacológico , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Portador Sadio/prevenção & controle , Criança , China/epidemiologia , Atenção à Saúde/métodos , Eritromicina/administração & dosagem , Eritromicina/uso terapêutico , Feminino , Humanos , Incidência , Masculino , Penicilinas/administração & dosagem , Penicilinas/uso terapêutico , Faringite/tratamento farmacológico , Faringite/epidemiologia , Faringite/microbiologia , Faringe/microbiologia , Prevalência , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/prevenção & controle , Instituições Acadêmicas/estatística & dados numéricos , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/isolamento & purificação , Resultado do TratamentoRESUMO
Group A beta-hemolytic streptococcal (GAS) vulvovaginitis has been reported in prepubertal girls. In adult women, a vaginal carrier state has been described, but vulvovaginitis is rarely reported. We describe 2 cases of recurrent GAS vulvovaginitis in women whose husbands were gastrointestinal carriers of GAS. Characterization of the isolated strains demonstrated that identical emm types of GAS were shared by partners. Treatment of both partners resulted in resolution of vaginitis. On the basis of negative vaginal culture results obtained after treatment of each individual episode of vaginitis, we believe that the female patients were reinfected as a result of exposure to their husbands, with shedding likely to have occurred in bed. These cases reiterate the necessity for adequate screening of the patient's family and contacts in cases of recurrent GAS infection by culturing all potential areas of GAS carriage.
Assuntos
Transmissão de Doença Infecciosa , Infecções Estreptocócicas/transmissão , Streptococcus pyogenes/isolamento & purificação , Vulvovaginite/microbiologia , Adulto , Portador Sadio , Saúde da Família , Feminino , Humanos , Masculino , Recidiva , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/microbiologia , Vulvovaginite/diagnósticoRESUMO
BACKGROUND: The annual incidence of acute rheumatic fever (ARF) in Hawaii has remained several times higher than that in the continental United States, particularly among ethnic Polynesians. The emm types of Streptococcus pyogenes that are associated with this nonsuppurative complication have, to our knowledge, not been previously reported in Hawaii. METHODS: Patients with ARF were identified through an active surveillance system at Kapiolani Medical Center (Honolulu, HI), the only pediatric tertiary care referral hospital in Hawaii. Specimens were obtained by throat culture from patients who met the Jones criteria for ARF at the time of presentation (63 patients), prior to penicillin treatment, and from consenting family contacts (10 individuals). Eight patients and 2 close family contacts with positive throat culture results were identified from February 2000 through December 2005. Group A streptococci isolates were characterized by emm sequence typing. RESULTS: Unusual emm types were temporally associated with the onset of ARF. Emm types 65/69 (from 2 patients), 71, 92, 93, 98, 103, and 122 were isolated from the 8 patients with ARF, and emm types 52 and 101 were isolated from the 2 household contacts. CONCLUSIONS: So-called rheumatogenic emm types and/or serotypes, which were previously associated with ARF in the continental United States, were not found in this study. Instead, emm types that are not commonly included among group A streptococci isolates in the continental United States and that are seldom, if ever, temporally associated with ARF were identified. These findings suggest that unusual group A streptococci emm types play a significant role in the epidemiology of ARF in Hawaii.
Assuntos
Penicilinas/uso terapêutico , Febre Reumática/microbiologia , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/fisiopatologia , Streptococcus pyogenes , Doença Aguda , Adolescente , Antibacterianos/uso terapêutico , Criança , Pré-Escolar , Etnicidade , Havaí , Humanos , Incidência , Febre Reumática/tratamento farmacológico , Febre Reumática/epidemiologia , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes/classificação , Streptococcus pyogenes/isolamento & purificação , Estados UnidosRESUMO
Acute rheumatic fever is a serious autoimmune sequel of Streptococcus pyogenes infection. This study shows that serotype M3 and M18 S. pyogenes isolated during outbreaks of rheumatic fever have the unique capability to bind and aggregate human basement membrane collagen type IV. M3 protein is identified as collagen-binding factor of M3 streptococci, whereas M18 isolates bind collagen through a hyaluronic acid capsule, revealing a novel function for M3 protein and capsule. Following in vivo mouse passage, conversion of a nonencapsulated and collagen-binding negative M1 S. pyogenes into an encapsulated, collagen-binding strain further supports the crucial role of capsule in mediating collagen binding. Collagen binding represents a novel colonization mechanism, as it is demonstrated that S. pyogenes bind to collagen matrix in vitro and in vivo. Moreover, immunization of mice with purified recombinant M3 protein led to the generation of anti-collagen type IV antibodies. Finally, sera from acute rheumatic fever patients had significantly increased titers of anti-collagen type IV antibodies as compared with healthy controls. These findings may suggest a link between the potential of rheumatogenic S. pyogenes isolates to bind collagen, and the presence of collagen-reactive autoantibodies in the serum of rheumatic fever patients, which may form a basis for post-streptococcal rheumatic disease. These anti-collagen antibodies may form a basis for poststreptococcal rheumatic disease.
Assuntos
Antígenos de Bactérias , Colágeno Tipo IV/imunologia , Febre Reumática/imunologia , Febre Reumática/microbiologia , Streptococcus pyogenes/patogenicidade , Animais , Autoanticorpos/sangue , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/imunologia , Sequência de Bases , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Estudos de Casos e Controles , Colágeno Tipo IV/ultraestrutura , DNA Bacteriano/genética , Feminino , Humanos , Imunização , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Streptococcus pyogenes/genética , Streptococcus pyogenes/imunologiaRESUMO
BACKGROUND: Previously, we reported an unexpectedly large percentage of failures by penicillin to eradicate group A streptococci (GAS) from the upper respiratory tract. Because penicillin has been the recommended therapy for the treatment of GAS pharyngitis, our report prompted controversy. Data from clinical trials in which our laboratory has participated demonstrated marked variation in GAS eradication rates among clinical sites. The reasons for such variation have never been adequately examined. We performed statistical analyses of site variation in eradication rates to assess the potential effect on reported reduced penicillin efficacy. METHODS: Penicillin GAS eradication rates were compared using data from 4 large multisite pharyngitis treatment trials (75 clinical sites; 1158 subjects). Variation in eradication rates among clinical sites was statistically evaluated [chi(2) tests and generalized estimating equation (GEE) regression models]. RESULTS: There was significant site-to-site variation in GAS eradication rates in each of the trials (range, 17-100%; P < 0.005) as well as between separate trials (mean range, 58-69%; P < 0.033). GEE modeling indicated that GAS eradication rates were significantly higher for clinical sites participating in more than one clinical trial. CONCLUSIONS: The statistically significant site-to-site variation in penicillin eradication rates was related to factors (dependencies) at individual sites. Such factors may affect assessment of therapeutic efficacy and indicate a necessity for considering clinical site variation before reporting pooled efficacy data from multiple sites; combined data may result in misleading clinical implications. This is the first report documenting significant variation resulting from individual clinical site-related factors and offers a possible explanation for reduced penicillin eradication.
Assuntos
Antibacterianos/uso terapêutico , Ensaios Clínicos como Assunto/estatística & dados numéricos , Estudos Multicêntricos como Assunto/estatística & dados numéricos , Penicilina G Benzatina/uso terapêutico , Penicilina V/uso terapêutico , Faringite/tratamento farmacológico , Streptococcus pyogenes/efeitos dos fármacos , Antibacterianos/administração & dosagem , Humanos , Penicilina G Benzatina/administração & dosagem , Penicilina V/administração & dosagem , Faringite/microbiologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Análise de Regressão , Projetos de Pesquisa , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/classificação , Streptococcus pyogenes/isolamento & purificação , Falha de Tratamento , Resultado do TratamentoRESUMO
BACKGROUND.: Despite the significant burden of disease associated with infection by group A streptococcus (GAS), little is known about the human immune response to GAS antigens after natural infection. METHODS.: We evaluated 195 serum samples obtained prospectively over a consecutive 24-month period from 41 pediatric subjects who experienced a new pharyngeal GAS acquisition. An enzyme-linked immunoassay was used to determine the kinetics and antigen specificity of antibodies against 13 shared GAS antigens and 18 type-specific M peptides. The majority of the antigens tested are currently being considered as vaccine candidates. RESULTS.: Twelve M types of GAS were recovered from 41 subjects who experienced 51 new GAS acquisitions that elicited antibody responses against at least 1 of the 31 antigens tested (immunologically significant new GAS acquisitions). The immune responses to the 13 shared antigens were highly variable. Increases in antibody levels were detected against a mean of 3.5 shared antigens (range, 1-8). Antibody responses to the homologous M peptide were observed in 32 (63%) of the 51 episodes. Seven subjects acquired more than 1 M type of GAS. There were no new immunologically significant acquisitions of an M type against which the subject had preexisting antibodies to the homologous M peptide. Of the subjects with new GAS acquisition, 65% were asymptomatic, yet immune responses were detected against 1 or more GAS antigens. Immune responses to streptolysin O and/or deoxyribonuclease B were observed after 67% of the new GAS acquisitions. Persistently positive (>12 weeks) throat culture results were returned for 20% of the 41 subjects despite immune responses to homologous M peptides and/or shared antigens. CONCLUSIONS.: The availability of throat culture results, GAS isolates, and serial serum samples collected prospectively over a 2-year period of observation provided a unique opportunity for us to assess the serologic status of pediatric subjects before and after new pharyngeal acquisitions of GAS. With the exception of antibody responses to the homologous M peptides, no clear pattern of immune responses against the remaining GAS antigens was seen. There were no new immunologically significant acquisitions of emm types of GAS against which the subjects had preexisting elevated levels of antibodies against the homologous M peptide. The observation that 65% of new GAS acquisitions caused no symptoms yet were immunologically significant suggests that the majority of infections are not detected, which would result in missed opportunities for primary prevention of rheumatic fever and rheumatic heart disease with appropriate antimicrobial therapy.
Assuntos
Doenças Faríngeas/microbiologia , Infecções Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Adolescente , Anticorpos Antibacterianos/imunologia , Formação de Anticorpos/imunologia , Antígenos de Bactérias/imunologia , Criança , Ensaio de Imunoadsorção Enzimática , Humanos , Estudos Longitudinais , Doenças Faríngeas/imunologia , Estudos Prospectivos , Infecções Estreptocócicas/microbiologiaRESUMO
BACKGROUND: Group A streptococci (Streptococcus pyogenes; GAS) invades human epithelial cell lines. Failure of penicillin to eradicate GAS from the throats of patients, especially those who are GAS "carriers," has been increasingly reported. However, there has been no comprehensive evaluation of how effectively antibiotics that are used to treat GAS enter upper respiratory tract epithelial cells and kill internalized GAS. We examined the viability of ingested, intracellular GAS after epithelial cell exposure to antibiotics commonly recommended for therapy of GAS infections. METHODS: A human laryngeal epithelial cell line (HEp-2) was used. Three techniques were used to study antibiotic (penicillin V, erythromycin, azithromycin, cephalothin, and clindamycin) killing of ingested GAS: examination by electron microscopy of ultrathin sections of ingested GAS, qualitative determination of intra-epithelial cell antibiotic, and special stain evaluation of intracellular GAS viability after epithelial cell exposure to antibiotics. RESULTS: GAS survived intracellularly despite exposure of the GAS-containing epithelial cells to penicillin. In contrast, there was killing of ingested GAS after exposure of epithelial cells to either erythromycin or azithromycin. Electron microscopy confirmed a lack of intracellular GAS fragmentation (cell death) after exposure of epithelial cells to penicillin in contrast to obvious GAS fragmentation after epithelial cell exposure to erythromycin or azithromycin. Cephalothin, a cephalosporin, and clindamycin were more effective in killing ingested GAS than was penicillin, but they were less effective than erythromycin or azithromycin. CONCLUSIONS: These observations strongly suggest that if the GAS upper respiratory tract carrier state results from intra-epithelial cell GAS survival, the failure of penicillin to kill ingested GAS may be related to a lack of effective penicillin entry into epithelial cells. These unique observations may have clinical implications for understanding GAS respiratory tract carriers and managing GAS infections.