Usefulness of <i>Helicobacter pylori</i> stool antigen test to monitor response to eradication treatment in children

Oderda, Giuseppina; Rapa, Anna; Marinello, Daniela; Ronchi, Barbara; Zavallone, Annalisa

doi:10.1046/j.1365-2036.2001.00915.x

Cited by 41 publications

(32 citation statements)

References 9 publications

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“…Monoclonal antibodybased tests are widely accepted for clinical practice with humans since they are sensitive, specific, noninvasive, and easy to perform (1,7,8). Our results show a high sensitivity and specificity of the test for stool samples from mice, which is in agreement with the values given for humans by the manufacturer.…”

supporting

confidence: 78%

Evaluation of a Monoclonal Antibody-Based Test for Detection of Helicobacter pylori -Specific Antigen in Stool Samples from Mice

Crone

Symonds

Campbell

et al. 2004

Clin Vaccine Immunol

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A test using monoclonal antibodies for detection of antigen in stool samples was compared with culture and histology for noninfected (n ‫؍‬ 25), Helicobacter pylori-infected (n ‫؍‬ 25), and Helicobacter felis-infected (n ‫؍‬ 6) mice. Sensitivity and specificity were 96%. The monoclonal antibody-based test is therefore a noninvasive technique that is able to diagnose H. pylori infection in mice.Mice infected with Helicobacter pylori are a convenient animal model for investigations (5, 6); however, noninvasive techniques to assess infection status are limited. The "gold standard" technique for indicating gastric colonization by H. pylori is considered to be a culture of gastric tissue. This requires the animal to be sacrificed, as does any histological analysis, therefore preventing the same animal to be monitored before, during, and after treatment. A noninvasive technique for detection of H. pylori is a test using monoclonal antibodies for detection of antigen in stool samples from mice. The aim of the present study, therefore, was to assess the sensitivity and specificity of the H. pylori-specific antigen test. All experiments were approved by the animal ethics committee of the Women's and Children's Hospital, North Adelaide, South Australia.Female C57BL/6 mice (age, Ͼ7 weeks) were divided into three groups, noninfected (n ϭ 25), H. pylori-infected (n ϭ 25), and Helicobacter felis-infected (n ϭ 6), and housed separately. Inoculations with H. pylori (Sydney strain 1) (6) and H. felis (5, 6) were performed via gavages of 100-l suspensions (10 9 CFU/ml). Following an infection time of 4 weeks and by using age-matched noninfected controls, mouse fecal pellets were collected from each group. Mice were then sacrificed by CO 2 asphyxiation and cervical dislocation, after which the stomachs were excised for histological examination and bacterial culture. Paraffin-embedded sections were stained with hematoxylin and eosin for histology and with a modified May-Grünwald-Giemsa stain to assess bacterial colonization (4). Gastritis was assessed in the body and the antrum by using a modified Sydney grading system for gastritis (6). The severity of gastritis and bacterial colonization density were assessed blindly by an impartial observer.The remaining tissue was homogenized, and serial 10-fold dilutions were performed, with 200 l of each dilution for all mice plated out in duplicate on Helicobacter-selective agar. In addition, 200 l of each dilution of the homogenized stomachs of the H. felis-infected group were plated out in duplicate on Campylobacter-selective agar. Plates were incubated in a 10% CO 2 incubator set at 95% humidity at 37°C for 5 to 7 days.Fecal samples were stored at Ϫ20°C until analyzed. A monoclonal antibody-based enzyme-linked immunosorbent assay (FemtoLab H. pylori Cnx; Connex, Martinsried, Germany) was used to detect H. pylori-specific antigen in stool samples by a modified method. Briefly, the size of the stool sample was reduced (mean weight, 0.047 g; range, 0.015 to 0.200 g), and the stop solution fo...

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supporting

confidence: 78%

Evaluation of a Monoclonal Antibody-Based Test for Detection of Helicobacter pylori -Specific Antigen in Stool Samples from Mice

Crone

Symonds

Campbell

et al. 2004

Clin Vaccine Immunol

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“…(7,26). The lack of IgG seroconversion or IgM seropositivity in a small subsample supports the transient nature of these infections, although the validity of serology in young children is not well established (8,15,25).…”

Section: Discussionmentioning

confidence: 95%

Significance of Transiently Positive Enzyme-Linked Immunosorbent Assay Results in Detection of Helicobacter pylori in Stool Samples from Children

et al. 2005

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In young children, the significance of stool samples transiently positive for Helicobacter pylori antigen is unknown. As part of a larger prospective study on enteric infections, stool samples were obtained from 323 children at two time points 3 months apart and tested for H. pylori antigen using a commercially available enzymelinked immunosorbent assay (ELISA) test. Seminested PCR for a Helicobacter-specific 16S rRNA gene was performed on all 26 pairs reverting from positive to negative ( Helicobacter pylori chronically colonizes the human stomach. Little is know about the transmission of H. pylori, although most cases appear to be acquired in childhood. Because the date of acquisition of H. pylori is rarely known, most clinical and epidemiological studies have focused on chronic infection. Some data do indicate, however, that transient H. pylori infection can occur. For example, among patients who have been infected experimentally (10, 14) or endoscopically (12), the majority with reported follow-up had spontaneous resolution of infection. In children, transiently positive breath, serum, and stool antigen tests for H. pylori infections have been reported (17,21,24). The validity of these findings, however, has been uncertain due to the lack of standardization of these diagnostic tests in young children.In a cohort study designed to identify risk factors for H. pylori transmission, we collected two sequential stool samples from 323 children. Among these children, 26 reversions (i.e., transient stool positives) were discovered. We conducted a study to determine whether these transiently positive stool samples represent true transient infections or false-positive stool antigen tests. MATERIALS AND METHODSStudy participants. As part of a large cohort study on transmission of enteric infections (20), households with an index case of gastroenteritis, with at least one additional participating member, were recruited through cooperating community health care settings as well as community outreach. An index case was defined as a case of diarrhea with or without vomiting characterized by at least five stools per day and lasting no more than 14 days. There was no age restriction for index cases. Episodes of possible noninfectious etiology, such as pregnancy, poisoning, or drug effects, were excluded. This source population is predominately lowincome and Hispanic, including a large percentage of foreign-born people. A brief telephone interview confirming study eligibility was followed by a home visit within 14 days of the index case of gastroenteritis reported in the home. Visits were conducted by trained research staff fluent in the primary language of the home. After providing informed consent, a structured questionnaire was administered regarding household demographics, socioeconomic markers, risk factors for H. pylori infection, household composition, and family relationships. Blood samples were obtained from all consenting household members. Because of concerns about the accuracy of H. pylori serologic testing in you...

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“…A presença de anticorpos no soro, sem antígenos nas fezes, pode representar o desaparecimento da infecção, uma vez que o teste sorológico empregado nesta pesquisa indica unicamente uma exposição prévia ao microrganismo, mas não discrimina indivíduos sadios ou com infecção ativa 24 34 . Já o teste nas fezes pode ser usado para o diagnóstico inicial da infecção, quando o indivíduo ainda não apresenta níveis de anticorpos detectáveis, bem como para confirmar a erradicação da Helicobacter pylori após quatro semanas do término do tratamento, quando ainda são verificados anticorpos no soro 24 . O imunoensaio nas fezes foi aprovado pela Food and Drug Administration desde 1998, tanto para o diagnóstico como para o controle da terapia, inclusive em crianças 24 34 .…”

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Helicobacter pylori em crianças e associação de cepas CagA na transmissão mãe-filho na Amazônia brasileira

Cartágenes

Martins

Carneiro

et al. 2009

Rev. Soc. Bras. Med. Trop.

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A Helicobacter pylori é uma bactéria gram-negativa, microaerófila, cujo principal reservatório é o estômago de seres humanos, onde determina inflamação aguda e crônica e, quando a infecção não é tratada, permanece para sempre no hospedeiro, sendo raramente eliminada de forma espontânea 34 . Essa infecção representa um sério problema de saúde pública, pois pode evoluir com graves lesões precursoras de neoplasias nos indivíduos infectados 1 10 . Apresenta distribuição mundial, mas com prevalências maiores em países em desenvolvimento, relacionadas a fatores contextuais, tais como as precárias condições socioeconômicas e sanitárias dessas regiões 20 . Outras condições também parecem influenciar sua prevalência, como a idade 33 , fatores genéticos do hospedeiro 9 e da bactéria 8 , ABSTRACTThe prevalence of Helicobacter pylori infection was investigated in blood samples from 100 children aged 1 to 12 years and from their mothers, by means of the indirect hemagglutination and anti-CagA methods, using ELISA assays. From these 100 children, 79 stool samples were obtained and bacterial antigens in the stools were investigated using capture ELISA. The antigens were detected in 54.4% (43/79) of the children, and serum antibodies in 43% (34/79). These methods presented similar performance, with greatest disagreement among the children aged 1 to 4 years. The seroprevalence was 50% (50/100) among the children and 86% (86/100) among the mothers. Infected mothers represented a risk factor that was 19 times greater than that of seronegative mothers, with regard to infecting their children (p < 0.05), especially the mothers with CagA+ strains (p < 0.05). Direct person-to-person contact may be a transmission method for this infection. Key-words:Helicobacter pylori. Prevalence. CagA strains. Mother-child transmission. Brazil.ou mesmo os fatores ambientais, como hábitos alimentares 19 , consumo de bebidas alcoólicas e fumo 4 .A bactéria dispõe de genes específicos responsáveis pela sua virulência e patogenicidade, que codificam a citotoxina associada ao gene cagA (CagA), encontrado em aproximadamente 60% das cepas. Esta proteína bacteriana, altamente imunogênica é injetada no citoplasma da célula hospedeira e exerce um importante papel na indução de sinalização intracelular, promovendo múltiplas mudanças como a ativação da inflamação, conduzindo a severos danos à mucosa gástrica e duodenal, e à produção de anticorpos anti-CagA 8 10 18 . Na maioria dos casos, a infecção é adquirida na infância 5 ocorrendo um rápido aumento da taxa de prevalência, particularmente nos cinco primeiros anos de vida. É universalmente aceito que a bactéria apenas consiga alcançar a mucosa gástrica através da boca, pois se trata de um microorganismo não invasivo, que parece ser transmitido de pessoa a pessoa de forma direta ou indireta 11 . As principais rotas de transmissão são oral-oral, fecaloral e gastro-oral, pois antígenos da bactéria têm sido detectados na cavidade oral 32 , eliminados através das fezes 27 , como também em conteúdos de vômitos 21 . ...

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Usefulness of Helicobacter pylori stool antigen test to monitor response to eradication treatment in children

Cited by 41 publications

References 9 publications

Evaluation of a Monoclonal Antibody-Based Test for Detection of Helicobacter pylori -Specific Antigen in Stool Samples from Mice

Evaluation of a Monoclonal Antibody-Based Test for Detection of Helicobacter pylori -Specific Antigen in Stool Samples from Mice

Significance of Transiently Positive Enzyme-Linked Immunosorbent Assay Results in Detection of Helicobacter pylori in Stool Samples from Children

Helicobacter pylori em crianças e associação de cepas CagA na transmissão mãe-filho na Amazônia brasileira

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