13C-urea breath test to assess Helicobacter pylori bacterial load

BACKGROUND: Some authors have reported, using different protocols, that 13C-urea breath test (13C-UBT) is capable of assessing the intragastric Helicobacter pylori bacterial load, whereas others have not confirmed these data. Our aim is to evaluate the correlation between 13C-UBT values and H. pylori bacterial load. MATERIALS AND METHODS: One hundred ninety-two patients diagnosed H. pylori-positive by rapid urease test, histology, and 13C-UBT were enrolled. H. pylori bacterial load (H. pylori score) and gastritis activity (activity score) were evaluated according to the Updated Sydney System. 13C-UBT was performed according to the European Standard Protocol. Breath samples were obtained every 10 minutes for 60 minutes in 52 patients and at 30 minutes (T30) in 140 patients and analyzed by mass spectrometry. RESULTS: At T30, mean +/- SD excess delta 13CO2 excretion was 17.4 +/- 1.1, 29.9 +/- 2.2, and 48.7 +/- 4.8 in patients with H. pylori scores 1, 2, and 3, respectively. This difference was statistically significant: H. pylori score 1 versus 2, p < .005; score 1 versus 3, p < .05; score 2 versus 3, p < .05. A significant positive correlation (G = 0.59) was found between H. pylori score and activity score of chronic gastritis. At T40 and T50 significant correlation between mean excess delta 13CO2 excretion and bacterial load was achieved only in patients with H. pylori scores 1 and 3. CONCLUSIONS: 13C-UBT European Standard Protocol values correlate with H. pylori bacterial load and the activity of gastritis at T30 breath sampling time.     

Role of 13C-urea breath test in experimental model of Helicobacter pylori infection in mice

Background: Animal models have been widely used to study Helicobacter pylori infection. Evaluation of H. pylori infection status following experimental inoculation of mice usually requires euthanasia. The ¹³C‐urea breath test (¹³C‐UBT) is both sensitive and specific for detection of H. pylori in humans. Thus, it would be very useful to have such a test with the same accuracy for the follow‐up of this infection in animal models of gastric infection. Accordingly, the purpose of this study was to develop and evaluate a ¹³C‐UBT method for following the course of H. pylori infection in a mouse model. Material and Methods: A total of 50 female C57BL/6 mice were gavaged three times with either 10⁸ colony‐forming units of H. pylori (n = 29) or saline solution only (n = 21). After 2 months of infection, mice were fasted for 14 hours and ¹³C‐UBT was performed using 300 μg of ¹³C‐urea. The mice were killed, and the stomach was removed and processed for immunohistochemistry and PCR. Results: The optimal time for breath sample collection in mice was found to be 15 minutes. The ¹³C‐UBT cutoff was set at 3.0‰δPDB. Using PCR as the gold standard, the sensitivity of ¹³C‐UBT and immunohistochemistry was 96.6 and 72.4%, respectively, while the specificity was 85.7 and 95.2%, respectively. Conclusions: ¹³C‐UBT was shown to be a reliable method for the detection of H. pylori infection in C57BL/6 mice and was even more accurate than immunohistochemistry. The use of ¹³C‐UBT in the mouse model of H. pylori infection can be very useful to detect the bacterium without the need to kill the animals in long‐term time course studies.     

13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a systematic review and meta-analysis

Background: The ¹³C‐urea breath test (¹³C‐UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta‐analysis to evaluate the performance of the ¹³C‐UBT diagnostic test for H. pylori infection in children. Methods: We conducted a systematic review of the PubMed, Embase and Liliacs databases including studies from January 1998 to May 2009. Selection criteria included studies with at least 30 children and reporting the comparison of ¹³C‐UBT against a gold standard for H. pylori diagnosis. Thirty‐one articles and 135 studies were included for analysis. Children were stratified in subgroups of <6 and ≥6 years of age, and we considered variables such as type of meal, cutoff value, tracer dose, and delta time for the analysis. Discussion: The ¹³C‐UBT performance meta‐analyses showed 1, good accuracy in all ages combined (sensitivity 95.9%, specificity 95.7%, LR+ 17.4, LR? 0.06, diagnostic odds ratio (DOR) 424.9), 2, high accuracy in children >6 years (sensitivity 96.6%, specificity 97.7%, LR+ 42.6, LR? 0.04, DOR 1042.7), 3, greater variability in accuracy estimates and on average a few percentage points lower, particularly specificity, in children ≤6 years (sensitivity 95%, specificity 93.5%, LR+ 11.7, LR? 0.12, DOR 224.8). Therefore, the meta‐analysis shows that the ¹³C‐UBT test is less accurate for the diagnosis of H. pylori infection in young children, but adjusting cutoff value, pretest meal, and urea dose, this accuracy can be improved.     

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

Objective: To evaluate the accuracy of ¹³C‐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.     

13C-urea breath test and gastric mucosal colonization by Helicobacter pylori in children: quantitative relation and usefulness for diagnosis of infection

Objective. Because in children Helicobacter pylori colonization could differ as compared to that in adults, gastric metabolism of urea and the reliability of the breath test must be evaluated. The aim of this study was to quantify the relationship between breath test and colonization.
Methodology. We studied data from 50 endoscopies performed in 39 children and adolescents (20 girls, 19 boys, aged 3–18 years); 28 were infected with H. pylori. Biopsies were analyzed for histological and microbiological diagnosis of infection and for quantitative antral culture of H. pylori. A ¹³C urea breath test was performed on the same day as that of endoscopy ( n = 33) or delayed between 2 and 90 days ( n = 17).
Results. Using a cut-off value of 3 δ‰, sensitivity was 96.5%, and specificity was 91.5%. The three children showing discrepancies between breath test and biopsy results had a δ‰ value close to the cut-off. For the 26 cases with a positive culture, we noted a significant correlation (r = 0.63; p < .001) that was not affected by the delay between breath test and gastroscopy.
Conclusion. This quantitative relation between bacterial density and δ‰ permits increasing the reliability of the test by interpreting carefully those results that approach the cut-off value.     

13C-urea breath test results in pigs challenged with Helicobacter pylori or other urease producing bacteria

The gastric bacterial flora and its influence on the 13C-urea breath test (UBT) for detection of Helicobacter pylori infection was studied in a pig model. Seven SPF minipigs were used. H. pylori or a mix of other urease positive bacteria were administered orally. UBT, serum and biopsies for histology and culture were collected. Our results show that UBT is not specific for H. pylori in pigs as the gastric bacterial flora is responsible for the high UBT values observed. Furthermore, the Ellegaard G?ttingen SPF minipigs are not useful in an animal model for H. pylori studies.     

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 ¹³C‐urea breath test (¹³CUBT) 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.     

Factors affecting the validity of the 13C-urea breath test for in vivo determination of Helicobacter pylori infection status in a mouse model

Background. The mouse model using a human isolate of Helicobacter pylori is being widely accepted as an economical means of studying gastric infection. A noninvasive monitoring method would be useful for repeated testing to establish the time course of infection and the efficacy of treatments. In this study, we describe factors that affect interpretation of ¹³C urea breath test results for the assessment of H. pylori infection status in this model.
Materials and Methods. Female C57Bl/6 mice that underwent gavage with H. pylori or saline were breath-tested using 50 μg of ¹³C urea at intervals up to 2 months after inoculation. The generation of ¹³CO₂ (excess δ¹³CO₂) by infected mice was compared to that of uninfected controls. The effects of diet, fasting, and coprophagy on the reliability of the ¹³C urea breath test were quantitated.
Results. Both commercial and synthetic mouse diets exhibited marked in vitro urease activity. A minimum fasting time of 13 hours prior to breath testing significantly reduced this dietary contribution to excess δ¹³CO₂ values. The coprophagic tendency of the mice caused spuriously high excess δ¹³CO₂ counts in the breath of both control and H. pylori –infected mice.
Conclusions. Although the dietary contribution to spuriously high values of excess δ¹³CO₂ in mice breath-tested for H. pylori infection was reduced by fasting, the high nonspecific urease activity generated by coprophagy severely limited the reliability of the urea breath test in the assessment of H. pylori infection status.     

电离测量法14C-尿素呼气试验诊断幽门螺杆菌的感染

目的建立一种电离测量法14G尿素呼气试验,用于快速检测幽门螺杆菌感染.方法口服14C尿素胶囊后,呼气14CO2直接采集于Ca(OH)2干粉垫上,14C吸收量以双盖勒计数检测.结果与经典液体闪烁测量法比较.81例幽门螺杆菌阳性和102例阴性病人接受验证试验.结果电离测量法诊断的准确性为略低于液体闪烁测量法的,但统计学差异无显著性(92.3%和96.2%,P＞0.05),标本重复测试结论变更率略高于液体闪烁测量,差异无显著性(6.0%和2.2%,P＞0.05).结论电离测量法14C-尿素呼气试验可用于医生办公室现场快速幽门螺杆菌感染诊断.     

13C-Urea breath test is superior in sensitivity to detect Helicobacter pylori infection than either antral histology or rapid urease test.

There is no single technique which fulfils the criterion for a reference method to detect Helicobacter pylori (Hp) infection. The aim was to compare the results of antral histology (H), rapid urease test (U) and urea breath test (UBT) from antral biopsy samples in patients having gastric or duodenal lesions during upper GI endoscopy. We used the following methods: 1) biopsy specimens for histology (Warthin-Starry staining); 2) rapid urease test; and 3) 13C-urea breath test with infrared spectrometry. The total number of patients was 166 examined by H, U, and UBT. H, U and UBT were negative (-) in 64 patients and positive (+) in 51. The true positivity and false negativity (%, number of patients in parentheses) of each method based upon the positivity of the other two tests were: H+, U+ (54): UBT+, 94.4% (51) and UBT-, 5.6% (3); H+, UBT+ (57): U+, 89.5% (51) and U-, 10.5% (6); U+, UBT+ (65): H+, 78.5% (51) and H-, 21.5% (14). If Hp infection is considered to be positive when at least two tests detect the presence of Hp, UBT shows the highest sensitivity in comparison to histology of biopsy specimens and urease test. UBT is highly recommended as a screening test for Hp infection in patients presenting upper GI endoscopic alterations.     

Role of noninvasive tests (C-urea breath test and stool antigen test) as additional tools in diagnosis of Helicobacter pylori infection in patients with atrophic body gastritis

BACKGROUND: Detection of Helicobacter pylori infection in atrophic body gastritis (ABG) is difficult, as during progression of body atrophy, H. pylori disappears. AIM: To increase the diagnostic yield of detection of active H. pylori infection in atrophic body gastritis patients by using noninvasive tests such as (13)C-Urea Breath Test ((13)C-UBT) and H. pylori stool antigen test (HpSA) would be useful. PATIENTS: 27 consecutive patients with newly-diagnosed atrophic body gastritis (19F/7M, age 27-73 years). METHODS: Gastroscopy with biopsies (antrum n = 3, body n = 3) and histology according to updated Sydney system, H. pylori IgG serology, (13)C-UBT, and HpSA. RESULTS: All tests used in the diagnosis of H. pylori infection were in agreement in 9/27 atrophic body gastritis patients (33.3%), being all positive in four (14.8%) and all negative in five patients (18.5%). Ten of the 27 (37%) patients were Giemsa stain-positive and serology-positive (group I). Seventeen of the 27 (63%) patients were Giemsa stain-negative: 5/17 with positive serology (group II) and 12/17 with negative serology (group III). In group I, 5/10 (50%) were (13)C-UBT positive and 4/10 (40%) HpSA positive. In group II, two patients were (13)C-UBT positive, but all were HpSA negative. Also in group III, all patients were HpSA negative, but one had a positive (13)C-UBT. CONCLUSIONS: In atrophic body gastritis patients, neither (13)C-UBT nor HpSA per se add useful information regarding active H. pylori infection, but these noninvasive tests may be important in combination with histology and serology to define the H. pylori status in some atrophic body gastritis patients.     

Review: Helicobacter pylori infection in children

Helicobacter pylori infection in children and adolescents differs in comparison to adults with respect to epidemiology, host responses, and disease manifestations. Furthermore, treatment options are limited in this population and antibiotic resistance rates continue to increase. Therefore, ongoing research is vital to understand disease pathogenesis and provide optimal management of children with infection. This review summarizes relevant publications from April 2019 to March 2020. Similar to adults, recent studies show a decreasing prevalence of infection in the pediatric population. Studies of pathogenesis investigated serum immune responses and the potential inverse association of infection and allergy. Several studies investigated the effect of H pylori and related inflammation on the gut microbiome. The recommendation of endoscopy‐based testing to identify the cause of symptoms and not just H pylori, reserving noninvasive UBT or stool antigen tests for post‐eradication follow‐up, was supported by the current literature.     

Organ-specific autoantibodies in children with Helicobacter pylori infection

BACKGROUND: We compared the prevalence of organ-specific autoantibodies in a group of Helicobacter pylori infected children and a group of uninfected children and investigated the relationship between the presence of relevant autoantibodies and the status of the target organs. PATIENTS AND METHODS: One hundred and twenty-four children with dyspepsia (54 boys, 70 girls; mean age 10.5 years; range 4-19) underwent gastroscopy: 56 had H. pylori infection (31 girls, 25 boys), while 68 (37 girls and 31 boys), were H. pylori-negative. All sera were tested for the presence of: parietal cell autoantibodies (PCA), intrinsic factor autoantibodies (IFA), microsomial autoantibodies, thyroglobulin autoantibodies, islet cell autoantibodies, glutamic acid decarboxylase autoantibodies, adrenal cortex autoantibodies, steroid-producing cell autoantibodies; gastrin, pepsinogen A, pepsinogen C and anti-H. pylori antibodies. The histological features and the ureA and cagA genes were also considered. RESULTS: The frequency of organ-specific autoantibodies was higher in patients with H. pylori infection than in uninfected patients (chi2-test p < .0001). Specifically gastric autoantibodies were significantly higher: seven of the 56 H. pylori-positive children were PCA-positive and one was IFA-positive (chi2-test p = .0004). The presence of autoantibodies was not associated with any clinical or biohumoral signs of disease. CONCLUSIONS: Our study detected a relationship between H. pylori infection in childhood and the presence of organ-specific autoantibodies unassociated with any clinical or biohumoral signs of disease. Helicobacter pylori infection in childhood could trigger the onset of clinical autoimmune gastritis, and/or other clinical autoimmune diseases.     

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti‐Helicobacter pylori IgG antibodies

Background

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti‐ H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

Methods

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti‐ H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

Results

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti‐ H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

Conclusions

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.     

New immunoassay for the detection of Helicobacter pylori infection compared with urease test, 13C breath test and histology: validation in the primary care setting.

Helicobacter pylori plays a major role in peptic ulcer disease and, as a result, testing for H. pylori infection among patients with dyspepsia has often been advocated. The aim of the study was to determine the diagnostic accuracy, the analytical performance, and optimal cut-off point of a new serological assay, the Pyloriset EIA-G III for the detection of H. pylori infection in the primary care setting. For 113 primary care patients with dyspepsia urea breath test, CLO test, histology and serology tests were performed. Diagnostic accuracy of the Pyloriset EIA-G III was evaluated against a reference standard of a carbon urea breath test (CUBT), CLO test and histology (from gastric biopsies). Precision, linearity and correlation of the serological assay with the CUBT and former Pyloriset were also determined. At the optimal cut-off level of 40 U/ml, the positive predictive value was 92.1%, negative predictive value 96.3%, sensitivity 87.5%, and specificity 93.9%. The within-run precision was high. The recovery data were good. The correlation of both CUBT and the former Pyloriset EIA-G and the Pyloriset EIA-G III was high. At the cut-off level of 40 U/ml, the new Pyloriset EIA-G III is a reliable method to detect H. pylori infection in the primary care setting.