Diagnosis of <i>Helicobacter pylori</i> Infection

Monteiro, Lurdes; Oleastro, Mónica; Lehours, Philippe; Mégraud, Françis

doi:10.1111/j.1523-5378.2009.00707.x

Cited by 16 publications

(13 citation statements)

References 54 publications

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“…Real-time PCR is faster and offers several important advantages over conventional PCR; quantification and possibility for detection of mutations associated with antibiotic resistance. 1,20,28,29 Real-time PCR has therefore become the routine method for detecting H. pylori in our hospital.…”

Section: Articlementioning

confidence: 99%

Polymerase chain reaction versus culture in the diagnosis of Helicobacter pylori infection

Johannessen

Bergh

Jianu

et al. 2013

Gastroenterol Insights

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In the management of Helicobacter pyloriinduced gastroduodenal disease, a pilot study at our hospital (St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway) revealed that culture often seemed to fail compared to the polymerase chain reaction (PCR). A more thorough evaluation was therefore undertaken. We included 201 patients referred to upper gastrointestinal endoscopy in the period [2002][2003][2004]. Serology, biopsy rapid urease test, culture and PCR were performed. Conventional PCR was performed using the ureC, vacA and cagA genes, and real-time PCR for ureC. A diagnostic standard was defined on the basis of all four tests, and all four tests were then compared to this standard. One hundred eleven patients were deemed H. pylori-positive by the defined diagnostic standard, and 90 were labeled negative. Compared to this standard, culture showed a sensitivity of 87.4%, which was significantly lower than PCR at 99.1% (P<0.001). Culture showed a perfect specificity of 100%, which was significantly better than PCR at 97.8%. ureC was the gene with the best sensitivity (94.6% in conventional PCR, 97.3% in real-time PCR). vacA sensitivity was 87.4%, which is significantly lower than ureC (P<0.001). cagA was present in 37.8% of our H. pylori-positive patients. By real-time PCR a significantly lower cycle threshold was observed in antral biopsies than in corpal biopsies, indicating a higher H. pylori DNA template concentration in antral biopsies. PCR-testing for H. pylori is faster and significantly more sensitive than culture. Culture on the other hand was significantly more specific than PCR in our hand.

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Section: Articlementioning

confidence: 99%

Polymerase chain reaction versus culture in the diagnosis of Helicobacter pylori infection

Johannessen

Bergh

Jianu

et al. 2013

Gastroenterol Insights

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“…Also, it has been observed that the positivity for CagA antibodies has the ability to predict the development of atrophy and appears related with young gastric cancer cases (10). However, the accuracy of the tests developed with this regard has been questioned because the results differed when they were used in different populations.…”

Section: Discussionmentioning

confidence: 99%

“…Among all, the serologic methods have been successfully used due to the immunogenicity of this protein and the non-invasivity of the method (10). In addition, it has been observed that CagA seropositivity is able to predict the development of atrophy and constitute a risk factor for intestinal metaplasia (11).…”

Section: Introductionmentioning

confidence: 99%

Clonaje y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico

et al. 2013

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Introduction:Helicobacter pylori strains expressing cytotoxic CagA protein are more commonly associated with peptic ulceration, atrophic gastritis and gastric adenocarcinoma than those lacking CagA. Determination of anti-CagA antibodies, therefore, acquires a relevant clinical significance in the serological detection of H. pylori infection and disease risk prediction. However, the CagA-serology has been questioned due to the differences found in their performance evaluations in different populations. Objective: To obtain a recombinant CagA fragment useful for serodiagnosis of H. pylori infection Methods: A fragment of the cagA gene was cloned into a prokaryotic T7 RNA polymerase expression vector. A recombinant C-terminal His 6 -tagged CagA was expressed, subsequently solubilized with urea and purified by immobilized metal affinity chromatography. The performance of the recombinant protein was evaluated using 180 human serum samples with an in-house Western blot assay compared to the Helicoblot 2.1 reference test. Results: The expressed His 6 -tagged CagA showed an immunoreactive 80kDa band as was revealed by SDS-PAGE and Western blot analysis using two different specific anti-CagA polyclonal antibodies. The recombinant protein was successfully purified obtaining a 93% of purity. The performance analysis of the purified recombinant antigen showed good immunoreactivity and exhibited values of sensitivity, specificity and accuracy of 88.1%, 100% and 92.7%, respectively. Conclusion: The CagA fragment of the study may constitute a useful tool for serological diagnosis of CagA-positive H. pylori infection. Clonación y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico Introducción. Las cepas de Helicobacter pylori que expresan la citotoxina CagA, se asocian más frecuentemente con úlcera péptica, gastritis atrófica y adenocarcinoma gástrico que las que carecen de esta citotoxina. Por lo anterior, el determinar la presencia de anticuerpos anti-CagA adquiere gran importancia clínica en la detección serológica de la infección por H. pylori y la predicción del riesgo de enfermedades. Sin embargo, los métodos serológicos que emplean CagA han sido cuestionados debido a las diferencias encontradas en las evaluaciones de su desempeño en diversas poblaciones. Objetivo. Obtener un fragmento recombinante de la proteína CagA para el serodiagnóstico de la infección por H. pylori. Materiales y métodos. Un fragmento del gen cagA fue clonado en un vector de expresión procariota que contenía el promotor de la T7 ARN polimerasa. El fragmento de la proteína CagA con seis histidinas en la región C-terminal, se expresó, se solubilizó con urea y se purificó por cromatografía de afinidad con iones metálicos inmovilizados. El desempeño de la proteína recombinante se evaluó empleando un método in house de Western Blot y 180 sueros humanos. Los resultados se compararon con la prueba de referencia Helicoblot 2.1. 547 Biomédica 2013;33:546-53 Recombinant CagA fragment fo...

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“…The reliability of serological kits for H. pylori infection has been widely confirmed [21], contributing to the reputation of serology as a simple, minimally invasive and inexpensive diagnostic and screening test. The best available serology test at the time of the study was the Pyloriset® an EIA-G from Orion Diagnostica, Espoo, Finland, with a specificity of 79–91% as assessed in previous studies in the Netherlands, including patients on acid suppressive therapy [22–24].…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Efficacy of serology driven “test and treat strategy” for eradication of H. pylori in patients with rheumatic disease in the Netherlands

Leest

Steen

Lems

et al. 2011

Eur J Clin Microbiol Infect Dis

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The treatment of choice of H. pylori infections is a 7-day triple-therapy with a proton pump inhibitor (PPI) plus amoxicillin and either clarithromycin or metronidazole, depending on local antibiotic resistance rates. The data on efficacy of eradication therapy in a group of rheumatology patients on long-term NSAID therapy are reported here. This study was part of a nationwide, multicenter RCT that took place in 2000–2002 in the Netherlands. Patients who tested positive for H. pylori IgG antibodies were included and randomly assigned to either eradication PPI-triple therapy or placebo. After completion, follow-up at 3 months was done by endoscopy and biopsies were sent for culture and histology. In the eradication group 13% (20/152, 95% CI 9–20%) and in the placebo group 79% (123/155, 95% CI 72–85%) of the patients were H. pylori positive by histology or culture. H. pylori was successfully eradicated in 91% of the patients who were fully compliant to therapy, compared to 50% of those who were not (difference of 41%; 95% CI 18–63%). Resistance percentages found in isolates of the placebo group were: 4% to clarithromycin, 19% to metronidazole, 1% to amoxicillin and 2% to tetracycline.

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Diagnosis of Helicobacter pylori Infection

Cited by 16 publications

References 54 publications

Polymerase chain reaction versus culture in the diagnosis of Helicobacter pylori infection

Polymerase chain reaction versus culture in the diagnosis of Helicobacter pylori infection

Clonaje y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico

Efficacy of serology driven “test and treat strategy” for eradication of H. pylori in patients with rheumatic disease in the Netherlands

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