Current role of Helicobacter pylori stool tests

Helicobacter pylori as an Initiating Factor of Complications in Patients With Cirrhosis: A Single-Center Observational Study

Background and Aim: The relationship between liver cirrhosis and Helicobacter pylori (H. pylori) is a debatable matter. The aim of this study is to evaluate the possible association between H. pylori infection and liver cirrhosis. Methods: A single-center prospective cohort pilot study of 558 patients with cirrhosis was followed up for 1 year. Serum C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), vascular endothelial growth factor (VEGF) levels and Fecal H. pylori antigen were evaluated by enzyme-linked immunosorbent assay (ELISA). All patients with positive H. pylori were treated and then followed up for 3 months. Participants with eradicated H. pylori were followed up for one further year. Results: H. pylori-positive patients (48.4%) were associated with increased levels of serum CRP, TNF-α, IL-6, NO, and VEGF, as well as increased incidence of varices, portal hypertensive gastropathy, gastric antral vascular ectasia, hepatocellular carcinoma (HCC), spontaneous bacterial peritonitis, hepatic encephalopathy, portal vein thrombosis (PVT), and hepatorenal syndrome (all P < 0.05). Multivariate analysis models revealed that the presence of H. pylori was an independent risk variable for the development of portal vein thrombosis and hepatocellular carcinoma (P = 0.043, P = 0.037) respectively. After treatment of H. pylori infection, there was a significant reduction in all measured biochemical parameters and reported cirrhotic complications (all P < 0.05). Conclusion: Incidence of PVT and HCC development increased with H. pylori infection through increased inflammatory markers and vascular mediators. Moreover, its eradication may reduce the incidence of these complications.

Development of a loop-mediated isothermal amplification assay for rapid Helicobacter pylori detection

Infection with cagA-positive Helicobacter pylori is associated with gastric cancer. Molecular techniques are vital for accurate H. pylori diagnosis. We developed a loop-mediated isothermal amplification (LAMP) for detecting the H. pylori cagA gene and evaluated its use for clinical diagnosis. A LAMP primer set was designed to recognize the homologous regions of cagA gene sequences of 6 H. pylori strains. LAMP sensitivity was evaluated with serial dilutions of H. pylori ATCC 43504 and fecal specimens; specificity was evaluated with H. pylori ATCC 49396 and CIP 104086. The LAMP sensitivity for H. pylori specimens was 10^-1 cfu/tube (reaction time, 37 min), which was 10-fold more sensitive than polymerase chain reaction. LAMP was also highly sensitive and rapid for fecal specimens. It detected cagA gene from ATCC 49396 and CIP 104086. The findings suggest LAMP can be used for diagnosing and screening of H. pylori infections to decrease gastric cancer incidence.

Helicobacter pylori and non-alcoholic fatty liver disease: A new enigma?

BACKGROUND AND AIM

The relationship between Helicobacter pylori (H. pylori) and nonalcoholic fatty liver disease (NAFLD) is a matter of debate. We achieved this prospective work to study whether H. pylori infection is a risk factor for NAFLD.

METHODS

A cohort multicenter pilot study of 369 adults without NAFLD at baseline was followed up for 2 years. Serum leptin, insulin, tumor necrosis factor-α, adiponectin, and interleukin-6 were measured using an enzyme-linked immunosorbent assay (ELISA). Homeostasis model assessment of insulin resistance (HOMA-IR) and leptin/adiponectin ratio (LAR) were calculated. Fecal H. pylori antigen was measured by ELISA. A total of 127 participants with H. pylori positive were treated and then followed up for 3 months.

RESULTS

Helicobacter pylori-positive patients (46.3%) were associated with an increase in IR, proinflammatory cytokines, C-reactive protein (CRP), LAR, NAFLD-liver fat score (NAFLD-LFS), and hepatic steatosis index (HSI) (all P < 0.01). Multivariate analysis of NAFLD according to HSI and NAFLD-LFS reported that presence of H. pylori, LAR, CRP, IL-6, smoking, and age (all P < 0.01) were independent risk factors for the presence of NAFLD. Multiple models adjusted for potential mediators or confounders such as metabolic, inflammatory, and biochemical factors were constructed. After therapy of H. pylori infection, there was a significant reduction in lipogenic profile, IR, leptin, LAR, CRP, proinflammatory cytokines, HSI, and NAFLD-LFS, as well as, increasing HDL.

CONCLUSION

Helicobacter pylori infection was related to an increased risk of NAFLD development, through increased markers of IR, inflammatory mediators, and lipid metabolism. Moreover, its eradication can recover these NAFLD risk factors.

Detection of gastric Helicobacter spp. in stool samples of dogs with gastritis

The aim of this study was to determine the prevalence and identify the species of gastric Helicobacter in the stool of dogs with gastritis. The study was carried out on thirty dogs of different breeds, of both genders and of various ages, diagnosed with gastritis. Helicobacter spp. was detected in stool samples using the nested-PCR method. Helicobacter bacteria were identified in stool samples from seven (23.3%) dogs. Helicobacter heilmannii was found to be the most common species of gastric Helicobacter. Helicobacter salomonis was identified much less frequently, while Helicobacter felis, Helicobacter pylori and Helicobacter bizzozeronii were not detected in any of the samples.

Diagnostic accuracy of a rapid fecal test to confirm H pylori eradication after therapy: Prospective comparison with a laboratory stool test

AIM: To investigate the clinical performances of rapid stool test (ImmunoCard STAT HpSA, Meridian Diagnostic Inc.) in the evaluation of eradication therapy of H pylori and to compare it with a well-known and validated laboratory stool test (Amplified IDEA Hp StAR, Dako).

METHODS: Stool samples of 122 patients were evaluated after eradication therapy of H pylori. H pylori status was assessed by 13C-urea breath test (UBT). Stool specimens were tested using either the rapid immunoassay kit or the laboratory immunoassay kit.

RESULTS: Forty-three patients were infected and 79 non-infected. Sensitivity and specificity of ImmunoCard STAT and Hp StAR were 58.14% and 76.4%, and 97.47% and 98.73%, respectively (P > 0.05). Overall agreement between the two tests was 92.6% (113 of 122 cases).

CONCLUSION: ImmunoCard STAT seems to have rather low performances, and it cannot be regarded as a reliable tool in the post-treatment setting. Also Hp StAR cannot be recommended to confirm H pylori eradication after treatment.

Faecal antigen tests in the confirmation of the effect of Helicobacter eradication therapy

BACKGROUND

The frequent occurrence of Helicobacter pylori infection requires significant health care resources after eradication therapy. Therefore the non-invasive testing methods are required to alleviate the increased work-load of health care personnel and to allow an easy control of eradication therapy. Conventionally, the effect of eradication therapy has been confirmed with 13C-urea breath test 4-6 weeks after a completed eradication.

AIM

To assess the applicability of Helicobacter pylori stool antigen tests as alternatives to the breath test in the control of the effect of eradication therapy.

METHODS

Fifty patients were diagnosed Helicobacter-positive by endoscopy and histology as well as by rapid urease test from mucosal specimen. Four weeks after an eradication therapy the patients were subjected to 13C-urea breath test as well as to faecal Helicobacter pylori antigen tests with mono- and polyclonal primary antibodies.

RESULTS

The monoclonal and polyclonal stool tests had 94% and 88% sensitivity, and 100% and 97% specificity, respectively, in the detection of Helicobacter pylori infection as compared to the 13C-urea breath test. The non-invasive test results were completely parallel in patients with various grades of mucosal atrophy or intestinal metaplasia.

CONCLUSIONS

Monoclonal faecal Helicobacter pylori antigen test is slightly superior to the polyclonal test regarding the sensitivity in the detection of stool Helicobacter antigens. Due to their sufficient sensitivity and specificity, and to their practicability and cost-effectiveness, they can be recommended for non-invasive testing of Helicobacter pylori infection as alternatives to the 13C-urea breath test.

Evaluation of a new rapid immunoassay for the detection of Helicobacter pylori in faeces: a prospective pilot study

BACKGROUND

Detection of Helicobacter pylori antigen in faeces is a valid method to diagnose H. pylori infection. Presently available stool tests are performed in the laboratory, and diagnostic report is delayed.

AIM

To evaluate a new rapid stool test in a pre-treatment setting and to compare it with a validated laboratory stool test.

METHODS

A total of 105 patients underwent gastroscopy with brush cytology, and biopsies for histology and rapid urease test, to assess H. pylori presence. Helicobacter pylori-status was considered positive if at least two tests were positive; negative if all tests were negative; indeterminate if one test was positive and two negative. Stool specimens were tested using either a rapid immunoassay kit (ImmunoCard STAT) or a laboratory enzyme immunoassay kit (Hp StAR).

RESULTS

Sixty patients were infected with H. pylori, 44 non-infected, one indeterminate. The sensitivity and specificity of ImmunoCard STAT were 85 and 93%; those of Hp StAR were 88 and 100% (not significant).

CONCLUSIONS

ImmunoCard STAT seems a reliable method for detecting H. pylori in untreated patients. It could replace laboratory stool tests, as it is easy and can be performed quickly. These characteristics might be a breakthrough for diagnosing H. pylori in the doctor's office.