Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

Ramírez‐Lázaro, María José; Lario, Sergio; Casalots, Àlex; Sanfeliu, Esther; Boix, Loreto; García-Iglesias, Pilar; Sánchez-Delgado, Jordi; Montserrat, A.; Bella, María Rosa; Gallach, Marta; Sanfeliú, Isabel; Segura, Ferrán; Calvet, Xavier

doi:10.1371/journal.pone.0020009

Cited by 62 publications

(45 citation statements)

References 44 publications

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“…However, to date, very few studies have addressed the usefulness of these techniques, especially very sensitive and specific techniques, such as real-time PCR with an internal control, in bleeding patients (7,19,20,24).…”

Section: Discussionmentioning

confidence: 99%

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Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

et al. 2012

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The aim of this study was to determine the diagnostic usefulness of quantification of the H. pylori genome in detection of infection in patients with upper gastrointestinal bleeding (UGB). A total of 158 consecutive patients with digestive disorders, 80 of whom had clinical presentation of UGB, were studied. The number of microorganisms was quantified using a real-time PCR system which amplifies the urease gene with an internal control for eliminating the false negatives. A biopsy sample from the antrum and corpus of each patient was processed. The rapid urease test, culture, histological study, stool antigen test, and breath test were done. The gold standard was a positive culture or positive results in at least two of the other techniques. When a positive result was defined as any number of microorganisms/human cell, the sensitivity of real-time PCR was greater in bleeding patients, especially in the gastric corpus: 68.4% (95% confidence interval [CI], 52.3 to 84.5%) in non-UGB patients versus 91.5% (95% CI, 79.6 to 97.6%) in UGB patients. When a positive result was defined as a number of microorganisms/human cell above the optimal value that maximizes the Youden index (>3.56 microorganisms/human cell in the antrum and >2.69 in the corpus), the sensitivity and specificity in UGB patients were over 80% in both antrum and corpus. Our findings suggest that some bleeding patients with infection caused by H. pylori may not be correctly diagnosed by classical methods, and such patients could benefit from the improved diagnosis provided by real-time PCR. However, the clinical significance of a small number of microorganisms in patients with negative results in classical tests should be evaluated.

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Section: Discussionmentioning

confidence: 99%

“…However, various studies have shown that in cases of upper gastrointestinal bleeding due to peptic ulcers, PCR techniques for detecting the genome of the microorganism are more reliable than invasive techniques (19,20,24).…”

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confidence: 99%

Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

et al. 2012

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“…PCR and real-time PCR are the most frequently used methods. A study from Spain has shown that real-time PCR improves H. pylori detection in patients with peptic ulcer bleeding [40]. They selected 52 histology-negative formalin-fixed paraffin-embedded biopsy specimens obtained during peptic ulcer bleeding episodes and found that among them, 42 were false negatives.…”

Section: Molecular Methodsmentioning

confidence: 99%

Epidemiology and Diagnosis of Helicobacter pylori Infection

et al. 2012

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Medline, PubMed and the Cochrane databases were searched on epidemiology and diagnosis of Helicobacter pylori for the period of April 2011-March 2012. Several studies have shown that the prevalence of H. pylori infection is decreasing in adults and children in many countries. Various diagnostic tests are available, and most of them have high sensitivity and specificity. The Maastricht IV/Florence consensus report states that the urea breath test using 13 C urea remains the best test to diagnose H. pylori infection. Among the stool antigen tests, the ELISA monoclonal antibody test is recommended. All these tests were used, either as a single diagnostic test or in combination, to investigate H. pylori infection among different populations throughout the world. Of particular interest, current improvements in high-resolution endoscopic technologies enable increased diagnostic accuracy for the detection of H. pylori infection, but none of these techniques, at present, are specific enough for obtaining a real-time diagnosis of H. pylori infection.

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“…7 Interestingly, in these situations, a polymerase chain reaction (PCR) was able to detect a low-density infection in a significant number of patients. [8][9][10] The aims of the present study were:…”

Section: Introductionmentioning

confidence: 99%

Occult H. pylori infection partially explains ‘false‐positive’ results of ¹³ C‐urea breath test

et al. 2015

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Background: In a previous study, UBiT-100 mg, (Otsuka, Spain), a commercial 13 C-urea breath test omitting citric acid pretreatment, had a high rate of false-positive results; however, it is possible that UBiT detected low-density 'occult' infection missed by other routine reference tests. We aimed to validate previous results in a new cohort and to rule out the possibility that false-positive UBiT were due to an 'occult' infection missed by reference tests. Methods: Dyspeptic patients (n ¼ 272) were prospectively enrolled and UBiT was performed, according to the manufacturer's recommendations. Helicobacter pylori infection was determined by combining culture, histology and rapid urease test results. We calculated UBiT sensitivity, specificity, positive and negative predictive values (with 95% CI). In addition, we evaluated 'occult' H. pylori infection using two previously-validated polymerase chain reaction (PCR) methods for urease A (UreA) and 16 S sequences in gastric biopsies. We included 44 patients with a false-positive UBiT, and two control groups of 25 patients each, that were positive and negative for all H. pylori tests. Results: UBiT showed a false-positive rate of 17%, with a specificity of 83%. All the positive controls and 12 of 44 patients (27%) with false-positive UBiT were positive for all two PCR tests; by contrast, none of our negative controls had two positive PCR tests. Conclusions: UBiT suffers from a high rate of false-positive results and sub-optimal specificity, and the protocol skipping citric acid pre-treatment should be revised; however, low-density 'occult' H. pylori infection that was undetectable by conventional tests accounted for around 25% of the 'false-positive' results.

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Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

Cited by 62 publications

References 44 publications

Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

Epidemiology and Diagnosis of Helicobacter pylori Infection

Occult H. pylori infection partially explains ‘false‐positive’ results of ¹³ C‐urea breath test

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Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

Cited by 62 publications

References 44 publications

Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

Real-Time PCR for Diagnosing Helicobacter pylori Infection in Patients with Upper Gastrointestinal Bleeding: Comparison with Other Classical Diagnostic Methods

Epidemiology and Diagnosis of Helicobacter pylori Infection

Occult H. pylori infection partially explains ‘false‐positive’ results of 13 C‐urea breath test

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Occult H. pylori infection partially explains ‘false‐positive’ results of ¹³ C‐urea breath test