ABSTRACT BACKGROUND: Serological tests are practical, with low cost, but no noninvasive tests are available for diagnosing Helicobacter pylori (H. pylori) infection in Brazil. The aim here was to develop and validate enzyme-linked immunosorbent assay (ELISA) serological tests to detect anti-H. pylori immunoglobulin G antibodies, based on cultured strains from Brazilian patients. DESIGN AND SETTING: Cross-sectional, diagnostic accuracy study comparing a locally developed and validated ELISA and invasive tests among dyspeptic patients at two public hospitals in São Paulo, Brazil. METHODS: An ELISA test was prepared using whole-cell antigen from 56 strains. After genotypic characterization, it was standardized and optical density (OD) cutoffs were determined based on the serum antibody response of 100 H. pylori-negative samples, compared with 82 H. pylori-positive samples. Validation was performed on 174 symptomatic patients. RESULTS: The optimal OD cutoffs established (for monoclonal and polyclonal tests, respectively) were 0.167 and 0.164; overall ELISA sensitivity: 84.3%, 78.9%; specificity: 88.6%, 90.6%; positive predictive value (PPV): 75.4%, 80%; negative predictive value (NPV): 93.1%, 81.8%; accuracy: 87.3%, 86.2%; child and adolescent ELISA sensitivity: 74.2%, 81.8%; specificity: 90.8%, 86.7%; PPV: 66.6%, 84.3%; NPV: 95.8%, 84.8%; accuracy: 88.5%, 84.6; adult ELISA sensitivity: 84.4%, 75%; specificity: 86.9%, 93%; PPV: 81.8%, 78.3%; NPV: 88.9%, 91.8%; accuracy: 85.9%, 88.5%. CONCLUSION: The polyclonal serological test developed using local strains presented better diagnostic performance among children and adolescents, while the monoclonal test was better among adults. The results from both tests suggest that these in-house serological tests could be used to detect anti-H. pylori antibodies in our population, for screening purposes.

Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=-0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=-0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=-0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.

RACIONAL: Redução da prevalência de infecção por Helicobacter pylori tem sido relatada em alguns países. OBJETIVO: Avaliar, em crianças, a prevalência de infecção por H pylori em um período de 10 anos, realizando endoscopia digestiva alta. MÉTODOS: Estudo retrospectivo observacional. Os relatórios de 1.165 endoscopias digestivas altas realizadas em 10 anos em um hospital público da cidade de São Paulo, SP, foram revisados, sendo incluídas as primeiras endoscopias de pacientes com idade inferior a 18 anos. A infecção por H pylori foi definida pelo teste rápido da urease, com um fragmento de mucosa antral. RESULTADOS: A principal indicação de endoscopia foi dor epigástrica (47,4%). A prevalência de infecção foi 33,6% (12,8% em lactentes, 19,4% em pré-escolares, 28,8% em escolares e 46,3% em adolescentes). No primeiro ano de estudo foi 60,47%, e 30,43% no último. Entre os pacientes menores de 6 anos, houve diminuição na prevalência de 25% (1993-6) para 14.3% (2000-02), enquanto entre os pacientes maiores de 12 anos a diminuição foi de 55,5% (1993-6) para 39,6% (2000-02). A diminuição da prevalência foi significativa nos pacientes com dor epigástrica, nos quais passou de 48,2% (92/191) em 1993-6, para 41,9% (65/155) em 1997-9 e 27,7% (57/206) em 2000-02. CONCLUSÃO: O estudo sugere que houve diminuição significativa na prevalência da infecção por H pylori nos pacientes estudados. A tendência foi principalmente observada no grupo etário mais jovem e nos pacientes com dor epigástrica.

BACKGROUND: Decreasing prevalence of H pylori infection has been reported in some countries. AIM: To evaluate the prevalence of Helicobacter pylori infection in a 10-year period in children submitted to upper digestive endoscopy. METHODS: It was a retrospective observational study. The records of 1,165 endoscopies performed during a 10-year period in a public hospital of the City of São Paulo, SP, Brazil, in patients up to 18-year-old. Only the first endoscopy was considered. Helicobacter pylori infection was defined by the rapid urease test, performed with one fragment of antral mucosa. Chi-square for trend has been estimated to compare Helicobacter pylori prevalence across the period. RESULTS: The main indication for endoscopy was epigastric pain (47.4%). There were 392 patients with H pylori infection (33.6%), 12.8% being infants, 19.4% toddlers, 28.8% schoolchildren and 46.3% adolescents. Prevalence was 60.47% in the first year of the study and 30.43% in the last. Among the less than 6-year-old patients there was a decrease in infection prevalence from 25% for the 1993-6 period to 14.3% in the 2000-02 period, while among the over 12-year-old patients the decrease was from 55.5% in the first period to 39.6% in the latter. The decrease in H pylori infection prevalence was more intense within patients with epigastric pain, in which prevalence has decreased from 48.2% (92/191) in 1993-6, to 41.9% (65/155) in 1997-9 and 27.7% (57/206) in 2000-02. CONCLUSION: The study suggests a significant decrease in the prevalence of H pylori infection regarding the studied patients. The trend was mainly observed in the younger age group and in patients with epigastric pain.

Racional — Apesar da alta prevalência da infecção por Helicobacter pylori em países em desenvolvimento, existem poucos ensaios pediátricos avaliando o tratamento antimicrobiano para erradicação. Objetivo - Avaliar a eficácia de esquema tríplice contendo claritromicina, amoxicilina e omeprazol para erradicação da infecção por Helicobacter pylori durante 7 e 10 dias. Pacientes e Métodos - Vinte e cinco crianças e adolescentes Helicobacter pylori positivo com queixas dispépticas de forte intensidade foram submetidas a tratamento com amoxicilina (50 mg/kg/dia - dose máxima 1 g bid), claritromicina (30 mg/kg/dia - dose máxima 500 mg bid) e omeprazol (0,6 mg/kg/dia - dose máxima 20 mg bid), durante 7 e 10 dias. Após 2 meses, realizou-se controle clínico e biopsia gástrica para avaliar erradicação do Helicobacter pylori. Resultados - Helicobacter pylori foi erradicado em 16/25 pacientes (64% - IC(95%) = 45-83%), em 11/15 (73% - IC(95%) - 51-95%) que utilizaram esquema antimicrobiano por 10 dias e em 5/10 (50% - IC(95%) = 19-81%) que utilizaram o esquema por 7 dias. Houve boa aceitação do tratamento antimicrobiano e efeitos colaterais ocorreram em dois pacientes (8%). Conclusões - O índice de erradicação obtido (64%) foi de eficácia moderada. Os dados da presente série sugerem que o esquema antimicrobiano por 10 dias (73%) seja mais eficaz que o esquema por 7 dias (50%) para tratamento da infecção por Helicobacter pylori em nossa população, embora seja necessária amostragem maior.

Background — Helicobacter pylori infection presents high prevalence in developing countries, but there are few pediatric assays evaluating antimicrobial treatment. Objective - The aim of this study was to investigate Helicobacter pylori eradication rate using a short regimen (7 and 10 days) of triple therapy with clarithromycin, amoxicillin and omeprazole. Patients and methods - Twenty-five Hp positive patients who presented severe epigastralgia, were submitted to antimicrobial treatment with amoxicillin (50 mg/kg/day - maximum dose 1g bid), clarithromycin (30 mg/kg/day - maximum dose 500 mg bid) and omeprazole (0.6 mg/kg/day - maximum dose 20 mg bid) during 7 or 10 days. After 2 months, clinical symptoms were evaluated and gastric biopsies were taken to test Hp eradication. Results - Overall eradication rate was achieved in 16/25 patients (64% - IC(95%) = 45-83%), in 11/15 (73% - IC(95%) = 51-95%) patients who used 10 days therapy course and in 5/10 (50% - IC(95%) = 19-81%) who used 7 days therapy course. Eradication drugs were well accepted and adverse effects were reported in two patients (8%). Conclusions - This triple therapy regimen had moderate efficacy (64%). The data suggests that 10 days therapy course achieves better eradication rate (73%) than 7 days course (50%) to treat Hp infection in our population.

CONTEXTO: Vários métodos diagnósticos estão disponíveis para a detecção da infecção por Helicobacter pylori (Hp), porém, até o presente momento, não há um teste que possa ser utilizado isoladamente como padrão-ouro. OBJETIVO: Avaliar a acurácia de três métodos invasivos e dois não-invasivos na detecção da infecção por Hp em crianças e adolescentes sintomáticos. TIPO DE ESTUDO: Estudo coorte prospectivo. LOCAL: Ambulatório de Doença Péptica, Disciplina de Gastroenterologia Pediátrica, Universidade Federal de São Paulo / Escola Paulista de Medicina. PACIENTES: 47 pacientes sintomáticos que realizaram exame endoscópico devido a sintomas dispépticos. MÉTODOS DIAGNÓSTICOS: Exame endoscópico com biopsias gástricas para três métodos invasivos (teste rápido da urease, histologia e cultura) e dois métodos não-invasivos (teste sorológico ELISA industrializado e teste respiratório com uréia marcada com Carbono13). VARIÁVEIS ESTUDADAS: Sensibilidade, especificidade, valor preditivo positivo e negativo de cada método e taxas de concordância e discordância entre os métodos. RESULTADOS: 47 pacientes [idade média de 11a9m (DP 2a10m), 27 do sexo feminino e 20 do masculino], 62% deles com infecção por Hp. Todos os 5 métodos concordaram em 61%, sendo negativo em 21% e positivo em 40%. As maiores concordâncias entre dois métodos ocorreram entre os métodos invasivos: histologia e teste rápido da urease (89,6%) e entre a histologia e cultura (87,5%). A maior sensibilidade, considerando como Hp positivo, qualquer combinação de 3 ou mais testes, foi encontrada no teste rápido da urease (S=100%), seguido pela histologia, sorologia e o teste respiratório com uréia marcada com Carbono13 (S=93,1%) e por fim a cultura (S=79,3%). A maior especificidade foi obtida pela histologia e cultura (100%), seguidos pelo teste rápido da urease (84,2%), sorologia (78,9%) e teste respiratório com uréia marcada com Carbono13 (78,9%). CONCLUSÕES: Nossos resultados sugerem que, entre os métodos invasivos, a associação do teste rápido da urease e histologia constituem a melhor escolha para a detecção da infecção por Hp. Se os resultados da histologia e do teste rápido da urease forem discordantes é recomendada a sorologia.

CONTEXT: Multiple diagnostic methods are available for the detection of Helicobacter pylori infection, but at present no single one can be used as the gold standard. OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy of 3 invasive and 2 non-invasive methods for detection of Helicobacter pylori infection in symptomatic children and adolescents. DESIGN: Prospective cohort study SETTING: Peptic Disease outpatients service, Discipline of Pediatric Gastroenterology, Universidade Federal de São Paulo / Escola Paulista de Medicina. PATIENTS: Forty-seven patients who underwent endoscopy because of dyspeptic symptoms. DIAGNOSTIC METHODS: Endoscopy with gastric biopsies for 3 invasive (rapid urease test, histology and culture) and 2 non-invasive methods (a commercial ELISA serology and 13carbon urea breath test - isotope ratio mass spectrometry) for detection of Helicobacter pylori infection. MAIN MEASUREMENTS: Sensitivity, specificity, positive and negative predictive values of each method and agreement and disagreement rates between the methods. RESULTS: Forty-seven patients [mean age, 11y9mo (SD 2y10mo), 27 female and 20 male]; 62% of them were Helicobacter pylori-positive. All methods agreed in 61%, and were negative in 21% and positive in 40%. The greatest concordance between 2 methods occurred between the invasive methods: histology and rapid urease test (89.6%) and histology and culture (87.5%). The greatest sensitivity, considering Helicobacter pylori-positive cases, for any combination of 3 or more tests, was achieved by the rapid urease test (S=100%), followed by histology, serology and 13carbon-urea breath test (S=93.1%) and lastly by culture (S=79.3%). The highest specificity was obtained by histology (100%) and culture (100%), followed by the rapid urease test (84.2%), serology (78.9%) and 13carbon-urea breath test (78.9%). CONCLUSIONS: Our results suggest that among invasive methods, an association between the rapid urease test and histology constituted the best choice for the detection of Helicobacter pylori infection. If results of histology and the rapid urease test are different, serology may be recommended.