Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole

Testing for Helicobacter pylori in an era of antimicrobial resistance

Antimicrobial resistance in Helicobacter pylori has reached alarming levels and is compromising traditional empiric treatment of H. pylori. Antimicrobial susceptibility testing is routinely performed for infectious diseases when there is a risk of resistance and is now recommended to guide therapy for H. pylori. This mini-review overviews the current diagnostics for H. pylori with a focus on tests that enable susceptibility-guided treatment, including molecular tests performed directly on stool and endoscopically collected specimens.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Management of Helicobacter pylori infection: Guidelines of the Italian Society of Gastroenterology (SIGE) and the Italian Society of Digestive Endoscopy (SIED)

Helicobacter pylori infection is very common and affects more than one-third of adults in Italy. Helicobacter pylori causes several gastro-duodenal diseases, such as gastritis, peptic ulcer and gastric malignancy, and extra-gastric diseases. The eradication of the bacteria is becoming complex to achieve due to increasing antimicrobial resistance. To address clinical questions related to the diagnosis and treatment of Helicobacter pylori infection, three working groups examined the following topics: (1) non-invasive and invasive diagnostic tests, (2) first-line treatment, and (3) rescue therapies for Helicobacter pylori infection. Recommendations are based on the best available evidence to help physicians manage Helicobacter pylori infection in Italy, and have been endorsed by the Italian Society of Gastroenterology and the Italian Society of Digestive Endoscopy.

Lack of almagate interference in breath test results for Helicobacter pylori diagnosis (Almatest study)

OBJECTIVE

The ¹³C-urea breath test (UBT) is the most widely used non-invasive diagnostic test for Helicobacter pylori. Debate continues to surround the possible interference of antacid intake on its result. This study aims to confirm the non-interference of almagate in the determination of H. pylori by UBT.

PATIENTS AND METHODS

Observational, multicentre study in adult patients treated with almagate in whom a UBT (TAUKIT®) was indicated. When the UBT result was negative, use of almagate was stopped for 30 days and the UBT was repeated. When the result was positive, no further determinations were made. The primary endpoint was the percentage of patients who, having had a negative result in the first breath test, were positive in the second after having stopped taking almagate (UBT false negatives, possibly attributable to almagate).

RESULTS

Of the 167 evaluable patients, 59% were female, average age was 49 and 97% had gastrointestinal symptoms. The result of the first UBT was negative in 71% of cases. Of these, in the second UBT test after stopping the almagate, the negative result was confirmed in 97.5%. Out of the total number of cases evaluated, the rate of false negatives was 1.8%.

CONCLUSIONS

Taking almagate has minimal or no interference in the result of UBT for the diagnosis of H. pylori infection. It can therefore be used in the weeks prior to a UBT.

Previous Helicobacter pylori infection-induced atrophic gastritis: A distinct disease entity in an understudied population without a history of eradication

Individuals with chronic atrophic gastritis who are negative for active H. pylori infection with no history of eradication therapy have been identified in clinical practice. By excluding false-negative and autoimmune gastritis cases, it can be surmised that most of these patients have experienced unintentional eradication of H. pylori after antibiotic treatment for other infectious disease, unreported successful eradication, or H. pylori that spontaneously disappeared. These patients are considered to have previous H. pylori infection-induced atrophic gastritis. In this work, we define these cases based on the following criteria: absence of previous H. pylori eradication; atrophic changes on endoscopy or histologic confirmation of glandular atrophy; negative for a current H. pylori infection diagnosed in the absence of proton-pump inhibitors or antibiotics; and absence of localized corpus atrophy, positivity for autoantibodies, or characteristic histologic findings suggestive of autoimmune gastritis. The risk of developing gastric cancer depends on the atrophic grade. The reported rate of developing gastric cancer is 0.31%-0.62% per year for successfully eradicated severely atrophic cases (pathophysiologically equal to unintentionally eradicated cases and unreported eradicated cases), and 0.53%-0.87% per year for spontaneously resolved cases due to severe atrophy. Therefore, for previous H. pylori infection-induced atrophic gastritis cases, we recommend endoscopic surveillance every 3 years for high-risk patients, including those with endoscopically severe atrophy or intestinal metaplasia. Because of the difficulty involved in the endoscopic diagnosis of gastric cancer in cases of previous infection, appropriate monitoring of the high-risk subgroup of this understudied population is especially important.

IVTH BRAZILIAN CONSENSUS CONFERENCE ON HELICOBACTER PYLORI INFECTION

ABSTRACT Significant progress has been obtained since the III Brazilian Consensus Conference on H. pylori infection held in 2012, in Bento Gonçalves, Brazil, and justify a fourth meeting to establish updated guidelines on the current management of H. pylori infection. Therefore, the Núcleo Brasileiro para Estudo do Helicobacter pylori e Microbiota (NBEHPM), association linked to Brazilian Federation of Gastroenterology (FBG) held its fourth meeting again in Bento Gonçalves, RS, Brazil, on August 25-27, 2017. Twenty-six delegates, including gastroenterologists, endoscopists, and pathologists from the five regions of Brazil as well as one international guest from the United States, participated in the meeting. The participants were invited based on their knowledge and contribution to the study of H. pylori infection. The meeting sought to review different aspects of treatment for infection; establish a correlation between infection, dyspepsia, intestinal microbiota changes, and other disorders with a special emphasis on gastric cancer; and reassess the epidemiological and diagnostic aspects of H. pylori infection. Participants were allocated into four groups as follows: 1) Epidemiology and Diagnosis, 2) Dyspepsia, intestinal microbiota and other afections, 3) Gastric Cancer, and, 4) Treatment. Before the consensus meeting, participants received a topic to be discussed and prepared a document containing a recent literature review and statements that should be discussed and eventually modified during the face-to-face meeting. All statements were evaluated in two rounds of voting. Initially, each participant discussed the document and statements with his group for possible modifications and voting. Subsequently, during a second voting in a plenary session in the presence of all participants, the statements were voted upon and eventually modified. The participants could vote using five alternatives: 1) strongly agree; 2) partially agree; 3) undecided; 4) disagree; and 5) strongly disagree. The adopted consensus index was that 80% of the participants responded that they strongly or partially agreed with each statement. The recommendations reported are intended to provide the most current and relevant evidences to management of H. pylori infection in adult population in Brazil.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Modified Helicobacter test using a new test meal and a 13C-urea breath test in Helicobacter pylori positive and negative dyspepsia patients on proton pump inhibitors

AIM

To determine the sensitivity and specificity of the ¹³C-urea breath test (UBT) in patients taking proton pump inhibitors (PPIs), using a new test meal Refex.

METHODS

One hundred and fourteen consecutive patients with dyspepsia, 53 Helicobacter pylori (H. pylori) positive, 49 H. pylori negative, were included in the study. The patients were then given esomeprazole 40 mg for 29 consecutive days, and the ¹³C-UBT with the new test meal was performed the next morning.

RESULTS

The sensitivity of the ¹³C-UBT with a cut off 2.5‰ was 92.45% (95%CI: 81.79%-97.91%) by per-protocol (PP) analysis and 78.13% (95%CI: 66.03%-87.49%) by intention-to-treat (ITT) analysis. The specificity of the ¹³C-UBT test was 96.00% in the ITT population (95%CI: 86.29%-99.51%) and 97.96% in the PP population (95%CI: 89.15%-99.95%).

CONCLUSION

The new test meal based ¹³C-UBT is highly accurate in patients on PPIs and can be used in those unable to stop their PPI treatment.

Real-world Helicobacter pylori diagnosis in patients referred for esophagoduodenoscopy: The gap between guidelines and clinical practice

BACKGROUND AND AIMS

Histopathology is the most accurate test to detect H. pylori when performed correctly with unknown validity in daily practice clinic settings. We aimed to determine the rate of potentially false-negative H. pylori results that might be due to continued use of proton pump inhibitors (PPIs) in routine endoscopy practice. We also aimed to establish whether gastroenterologists recommend routine cessation of PPIs before esophagogastroduodenoscopy (EGD) and whether they regularly document that biopsies for H. pylori testing have been taken while the patients are on PPI treatment.

METHODS

Detailed information about three known factors (PPIs, antibiotics and prior H. pylori eradication treatment), which may cause histology or rapid urease test (RUT) to be unreliable, had been prospectively collected through interviews using a questionnaire before each test. Gastric biopsies were stained with H&E for histological analysis.

RESULTS

A total of 409 individuals at three academic gastroenterology institutions were tested 200 times with histology. Fifty-six per cent (68 of 122) of all negative tests fell in the category of continuing PPI use, which had the potential to make the histology and RUT results unreliable.

CONCLUSIONS

These data demonstrate a clear and important gap between current guidelines and real-world practice with regards to the diagnosis of H. pylori during EGD. A negative histology or RUT should be considered false negative until potential protocol violations are excluded. Documentation of PPI use during the EGD should be an integral part of the EGD report. The current practice of taking biopsies for H. pylori testing in patients under PPIs should be reevaluated.

Guidelines for the management of Helicobacter pylori infection in Italy: The III Working Group Consensus Report 2015

Knowledge on the role of Helicobacter pylori (HP) infection is continually evolving, and treatment is becoming more challenging due to increasing bacterial resistance. Since the management of HP infection is changing, an update of the national Italian guidelines delivered in 2007 was needed. In the III Working Group Consensus Report 2015, a panel of 17 experts from several Italian regions reviewed current evidence on different topics relating to HP infection. Four working groups examined the following topics: (1) "open questions" on HP diagnosis and treatment (focusing on dyspepsia, gastro-oesophageal reflux disease, non-steroidal anti-inflammatory drugs or aspirin use and extra-gastric diseases); (2) non-invasive and invasive diagnostic tests; (3) treatment of HP infection; (4) role of HP in the prevention of gastric cancer. Statements and recommendations were discussed and a consensus reached in a final plenary session held in February 2015 in Bologna. Recommendations are based on the best current evidence to help physicians manage HP infection in Italy. The guidelines have been endorsed by the Italian Society of Gastroenterology and the Italian Society of Digestive Endoscopy.

Evaluation of Exalenz Bioscience's BreathID for Helicobacter pylori detection

Carbon-labeled urea breath tests, which have high sensitivity and specificity, are the preferred method used in epidemiological studies, screening dyspeptic patients and assessing eradication or recurrence of Helicobacter pylori infection. The principle of the (13)C-urea breath test relies upon the ability of the H. pylori urease to hydrolyze the orally administered (13)C-urea. The BreathID (Exalenz Bioscience Inc., Union, NJ, USA) provides a competitive solution for breath testing, including unique features such as automatic continuous breath collection and analysis. This is an unattended convenient test, with no human error as the correct part of the breath is collected and patients' assistance is not required. The test results are available in real time at the point of care and enable shortened breath testing procedures. Additionally, several studies showing expanded utility of the BreathID in pediatrics, after therapy and during proton pump inhibitors intake, further support the safety and performance of the BreathID in the diagnosis of H. pylori.

[Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition]

Since the Korean College of Helicobacter and Upper Gastrointestinal Research has first developed the guideline for the diagnosis and treatment of Helicobacter pylori infection in 1998, the revised guideline was proposed in 2009 by the same group. Although the revised guideline was made by comprehensive review of previous articles and consensus of authoritative expert opinions, the evidence-based developmental process was not applied in the revision of the guideline. This new guideline has been revised especially in terms of changes in the indication and treatment of H. pylori infection in Korea, and developed by the adaptation process as evidence-based method; 6 guidelines were retrieved by systematic review and the Appraisal of Guidelines for Research and Evaluation (AGREE) II process, 21 statements were made with grading system and revised by modified Delphi method. After revision, 11 statements for the indication of test and treatment, 4 statements for the diagnosis and 4 statements for the treatment have been developed, respectively. The revised guideline has been reviewed by external experts before the official endorsement, and will be disseminated for usual clinical practice in Korea. Also, the scheduled update and revision of the guideline will be made periodically.

Applicability of a short/rapid 13C-urea breath test for Helicobacter pylori: retrospective multicenter chart review study

BACKGROUND

Carbon labeled urea breath tests usually entail a two point sampling with a 20 to 30-minute gap. Our aim was to evaluate the duration of time needed for diagnosing Helicobacter pylori by the BreathID® System.

METHODS

This is a retrospective multicenter chart review study. Test location, date, delta over baseline, and duration of the entire test were recorded. Consecutively 13C urea breath tests results were extracted from the files over a nine year period.

RESULTS

Of the 12,791 tests results, 35.1% were positively diagnosed and only 0.1% were inconclusive. A statistically significant difference in prevalence among the countries was found: Germany showing the lowest, 13.3%, and Israel the highest, 44.1%. Significant differences were found in time to diagnosis: a positive diagnosis had the shortest and an inconclusive result had the longest. Overall test duration averaged 15.1 minutes in Germany versus approximately 13 minutes in other countries. Diagnosis was achieved after approximately 9 minutes in Israel, Italy and Switzerland, but after 10 on average in the others. The mean delta over baseline value for a negative diagnosis was 1.03 ± 0.86, (range, 0.9 - 5), versus 20.2 ± 18.9, (range, 5.1 - 159.4) for a positive one.

CONCLUSIONS

The BreathID® System used in diagnosing Helicobacter pylori can safely shorten test duration on average of 10-13 minutes without any loss of sensitivity or specificity and with no test lasting more than 21 minutes.

[Effect of acid pump antagonist (Revaprazan, Revanex(R)) on result of 13C urea breath test in patients with Helicobacter pylori associated peptic ulcer disease]

BACKGROUND/AIMS

Revaprazan (Revanex(R)) is a novel proton pump inhibitor (PPI) that has a somewhat different effect on proton pump compared with the other PPI's, also (called as 'acid pump antagonist'). We aimed to examine the false negative rate of 13C-urea breath test (UBT) in the patients with Helicobacter pylori (H. pylori) associated peptic ulcer disease who were treated with revaprazan and evaluate the anti-urease activity of revaprazan.

METHODS

Total 55 patients were enrolled in this study. They received EGD examination between January 2009 and December 2009 and diagnosed histologically as H. pylori associated peptic ulcer disease. All patients took revaprazan only. Three patients were excluded because of underlying chronic disease and inappropriate breath sampling. The remaining 52 patients had UBT at 0, 2 and 4 weeks of revaprazan use. After 2 weeks of the cessation of revaprazan, they had the fourth UBT.

RESULTS

At 2 and 4 weeks, the false negative rates of UBT were 5.8% and 23.1%, respectively (p=0.05). After 2 weeks of the cessation, the cases of the false negative result were five. Four out of five patients had prolonged negative results on two or three successive tests, and baseline 13C difference value did not predict the false negative results.

CONCLUSIONS

False negative results of UBT were common and increased with prolonged use of acid pump antagonist. As PPI, it had also anti-urease activity and most patients (47/52, 90.4%) reverted to positive results by 2 weeks after the cessation of taking the medication.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Effect of omeprazole, rabeprazole, and rebamipide on the accuracy of urea breath test in patients with Helicobacter pylori infection

Background: The urea breath test (UBT) has been widely used for H. pylori eradication after treatment. The breath test could be adversely affected by various factors including proton pump inhibitors (PPIs) that are also used in the therapy for H. pylori infection. Objective: Determine the effect of omeprazole, rabeprazole and the mucoprotective agent rebamipide, on the UBT. Methods: Fifty-six patients with dyspepsia and positive for H. pylori by rapid urease test were enrolled. They were classified into three groups: Group 1 (n=25) received omeprazole 20 mg once daily, group 2 (n=13) received rabeprazole 20 mg once daily, and group 3 (n=18) received rebamipide 100 mg three times a day. All patients received a 14-day course of their medications. UBT was performed on day 0 as a baseline and on day 14 in all patients. In patient with negative results of UBT on day 14, the UBT was performed in consecutive week until the test became positive. Results: Fifty-six patients (20 men and 36 women) participated in the study. Their mean age was 46.77±14.3 years. False negative rate after 14-day treatment in omeprazole, rabeprazole and rebamipide group were 20.0%, 30.8%, and 0% respectively. There was a significant difference between 13C level in patients with negative and positive UBT results (2.7±0.7 vs.22.9±3.7/mL, p=0.025). The reversal of false negative to true positive tests occurred within two weeks after discontinuation of omeprazole and rabeprazole. Conclusion: Proton pump inhibitors had an effect on the accuracy of H. pylori detection using UBT. Rabeprazole revealed a higher false negative rate in the UBT than omeprazole. The mucoprotective drug, rebamipide, did not influence negative results in the UBT.

Performance of acidified 14C-urea capsule breath test during pantoprazole and ranitidine treatment

BACKGROUND AND AIM

Urea breath test (UBT) results could be false negative in patients taking antisecretory drugs. This effect would be prevented by citric acid administration during UBT. We prospectively investigated whether acidified 14C-urea capsule prevents false negative UBT results in patients taking antisecretory drugs and show interference with the duration of medications.

METHODS

Sixty Helicobacter pylori positive patients were included. Pantoprazole (40 mg/day) was given to 27 patients for 28 days and ranitidine (300 mg. o.d.) to 33 patients for 60 days. Urea breath tests were repeated on days 14 and 28 in both groups and on day 60 in the ranitidine group.

RESULTS

The baseline mean breath counts of two groups did not show any significant difference. Pantoprazole led to a significant decrease in mean breath counts on day 14 (P < 0.005). Six of 27 and 3 of 25 patients taking pantoprazole developed negative or equivocal UBT results on days 14 and 28, respectively. Two of 32, 2 of 32 and 3 of 21 patients taking ranitidine developed negative or equivocal UBT results on days 14, 28 and 60, respectively.

CONCLUSIONS

The use of acidified 14C-urea capsule did not prevent false negative UBT results in patients taking pantoprazole and ranitidine, and the duration of medication does not affect the test results.

Helicobacter pylori recurrence in developed and developing countries: meta-analysis of 13C-urea breath test follow-up after eradication

OBJECTIVE

Recurrence of Helicobacter pylori infection after eradication is rare in developed countries and more frequent in developing countries. Most recurrent cases are attributed to recrudescence (recolonization of the same strain within 12 months) rather than to reinfection (colonization with a new strain after more than 12 months). The aim of the study was to analyze recurrence rates in developed and developing countries and to deduce the relative roles of recrudescence and reinfection.

METHODS

The PubMed database was searched up to January 31, 2007 using the keywords "Helicobacter pylori" or "H. pylori" and "recurrence" or "recrudescence," or "reinfection." Only prospective case studies in adults that used the (13)C-urea breath test ((13)CUBT) were included. Meta-analyses were performed with statdirect Statistical software, version 2.6.1, StatsDirect Ltd, Chesire, UK.

RESULTS

The literature search yielded 10 studies of H. pylori recurrence in developed countries (3014 patients followed for 24-60 months) and 7 studies in developing countries (2071 patients followed for 12-60 months). The calculated annual recurrence rates were 2.67% and 13.00%, respectively. Nested meta-analysis of cases with a longer follow-up after eradication revealed an annual recurrence rate of 1.45% (RR 0.54) in developed countries and 12.00% (RR 0.92) in developing countries.

CONCLUSIONS

The similarity of the annual recurrence rates during the first year after eradication and the annual recurrence rates in the second year after successful eradication in developing countries supports reinfection as the main cause in the second period. Therefore, a different approach for follow-up of H. pylori eradication may be needed between developed and developing countries.

"Cervia II Working Group Report 2006": guidelines on diagnosis and treatment of Helicobacter pylori infection in Italy

Proper management of Helicobacter pylori infection in clinical practice--when supported by evidence-based data--is expected to produce substantial cost-efficacy advantages. This consideration has prompted the Cervia Working Group to organise a meeting of experts to update the National Guidelines on the diagnosis and treatment of H. pylori infection in Italy. Recommendations in the new European Guidelines were considered in the National setting, here in the light of factors such as the incidence of gastric cancer and gastric lymphoma, the accessibility to different diagnostic tools, the prevalence of bacterial resistance against antibiotics, and the availability of different drugs. The main revisions in respect to the previous guidelines include H. pylori eradication in non-ulcer dyspepsia patients and in non-steroidal, anti-inflammatory drug users, as well as in patients with idiopathic thrombocytopenic purpura and iron deficiency anaemia. The stool antigen test is now accepted as a valid test for confirmation of H. pylori eradication following therapy. New therapeutic approaches have been recommended for both first- (sequential therapy) and second-line (levofloxacin-based) treatment in our country.

13C-urea breath test during hospitalization for the diagnosis of Helicobacter pylori infection in peptic ulcer bleeding

OBJECTIVE

To evaluate the accuracy of (13)C-urea breath test (UBT) to detect Helicobacter pylori infection in patients hospitalized with peptic ulcer bleeding and treated with proton pump inhibitors (PPIs).

METHODS

Patients hospitalized with peptic ulcer bleeding, and treated with omeprazole, had a first UBT performed the day after resuming oral feeding. Patients with a negative UBT during hospitalization underwent a repeated UBT 15 days after stopping PPIs.

RESULTS

The first UBT during hospitalization was positive in 86% of 131 patients. Time between admission and performance of the test was longer in patients with negative versus positive UBT (5.2 +/- 0.7 versus 4.3 +/- 0.5 days; p < .001). The repeated UBT became positive in 15 of 18 (83%) patients with a negative first UBT. In the multivariate analysis, the only variable associated with a negative first UBT was the time elapsed between admission and performance of the test (odds ratio = 6.6; 95%CI = 2.9-15.1).

CONCLUSION

Most H. pylori-positive patients with ulcer bleeding have a positive UBT (performed just after resuming oral feeding) despite previous treatment with high-dose PPIs. Nevertheless, to preclude false-negative results due to PPI therapy, the UBT should be performed as early as possible. If the infection cannot be demonstrated with this first UBT, H. pylori still needs to be definitively excluded with a second UBT performed after stopping PPIs.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

The 13carbon urea breath test for the diagnosis of Helicobacter pylori infection in subjects with atrophic gastritis: evaluation in a primary care setting

BACKGROUND

(13)Carbon urea breath testing is reliable to detect current infection with Helicobacter pylori but has been reported to be of limited value in selected patients with atrophic body gastritis or acid-lowering medication.

AIM

To evaluate the accuracy of (13)carbon urea breath testing for H. pylori detection in 20 asymptomatic patients with histologically confirmed atrophic body gastritis in a primary care setting.

METHODS

(13)Carbon urea breath testing and serology were compared with H. pylori culture of a corpus biopsy as reference test.

RESULTS

All tests were in agreement in 12 patients, being all positive in six and all negative in six. One patient was positive for serology and culture but negative for (13)carbon urea breath testing, five patients had only positive serology and two patients had only positive (13)carbon urea breath testing. (13)Carbon urea breath testing showed an accuracy with culture of 85% and anti-H. pylori serology with culture of 75%. (13)Carbon urea breath testing carried out in patients with positive serology showed an accuracy of 92%. Receiver operating characteristic curve analysis of (13)carbon urea breath testing shows optimal discrimination at the prescribed cut-off value.

CONCLUSIONS

(13)Carbon urea breath testing can be used as diagnostic H. pylori test in asymptomatic patients with atrophic body gastritis, preferably in addition to serology, to select subjects for anti-H. pylori therapy.

Comparison of different protocols for 13C-urea breath test for the diagnosis of Helicobacter pylori infection in healthy volunteers

OBJECTIVE

The (13)C-urea breath test ((13)C-UBT) is the most accurate non-invasive method for diagnosis of Helicobacter pylori infection. However, several methodological issues have not been resolved yet. The aim of this study was to test different protocols of (13)C-UBT to find the optimal test drink and sampling interval.

MATERIAL AND METHODS

(13)C-UBT was performed at 3-day intervals in 27 healthy volunteers using citric acid (test A), orange juice (B) and still water (C) as test drinks. Breath samples were collected from time 5 to 60 min. A total number of 2106 breath samples were analysed by isotope ratio mass spectrometry (cut-off value 3.5).

RESULTS

Differences in delta values were greater than would be expected by chance (A versus B and A versus C at times 20, 25, 30, 35 and 40 min, p<0.05, Dunnett's method). There were no grey zone- or false-negative results among H. pylori-positive persons in test A at any time, but some were found in tests B and C. Optimal intervals for breath sampling are at times 20 or 25 min after (13)C-urea ingestion.

CONCLUSIONS

Citric acid solution as a test drink and 20- or 25-min breath sampling intervals are optimal for the (13)C-UBT in healthy volunteers.

Diagnosis of Helicobacter pylori Infection

A large number of studies on diagnostic tests have been published this year. New tests were proposed for the detection of Helicobacter pylori antigens in stools and new molecular methods (real-time polymerase chain reaction) to look for antimicrobial susceptibility. The other standard tests have been applied in different situations to improve the diagnosis of the infection.