Diagnosis of Helicobacter pylori infection

Traditional and Modern Diagnostic Approaches in Diagnosing Pediatric Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is the most common bacterial infection worldwide, is usually acquired during childhood and is related to gastric carcinogenesis during adulthood. Therefore, its early proper diagnosis and subsequent successful eradication represent the cornerstones of gastric cancer prevention. The aim of this narrative review was to assess traditional and modern diagnostic methods in terms of H. pylori diagnosis. Several invasive and non-invasive methods were described, each with its pros and cons. The invasive diagnostic methods comprise endoscopy with biopsy, rapid urease tests, histopathological exams, cultures and biopsy-based molecular tests. Among these, probably the most available, accurate and cost-effective test remains histology, albeit molecular tests definitely remain the most accurate despite their high costs. The non-invasive tests consist of urea breath tests, serology, stool antigens and non-invasive molecular tests. Urea breath tests and stool antigens are the most useful in clinical practice both for the diagnosis of H. pylori infection and for monitoring the eradication of this infection after therapy. The challenges related to accurate diagnosis lead to a choice that must be based on H. pylori virulence, environmental factors and host peculiarities.

Rapid and Sensitive Assay of Helicobacter pylori With One-Tube RPA-CRISPR/Cas12 by Portable Array Detector for Visible Analysis of Thermostatic Nucleic Acid Amplification

Helicobacter pylori (H. pylori) has infected more than half of the world’s population and is still a threat to human health. The urea breath test, despite being widely used in clinical diagnosis, still faces huge challenges in the immediate detection of H. pylori. Thus, a rapid, sensitive, and highly specific point of care diagnosis is particularly important for preventing the further transmission of H. pylori and for real-time monitoring of the disease in a given population. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics have been applied to various types of nucleic acid testing; however, there are often shortcomings of complex operation and high signal transmission background. In this study, we proposed a new platform for the assay of H. pylori using one-tube-based CRISPR/Cas12a diagnostic methods and designed a detector for this platform, which is a portable array detector for visible analysis of thermostatic nucleic acid amplification (Pad-VATA). By incorporating isothermal recombinase polymerase amplification, our platform could detect the conserved gene fragments of H. pylori with a constant low as 2 copies/μl. The assay process can be performed at a single temperature in about 30 min and integrated into the reactor in the palm-sized Pad-VATA to facilitate rapid diagnosis of H. pylori. We also verified the accuracy of our platform using 10 clinical samples and found that the platform can quickly detect H. pylori infection in a given population. We believe that this fast, convenient, efficient, and inexpensive screening and diagnostic platform can be widely used in various settings, including homes and clinics.

Investigation of the quantitative detection of serum Helicobacter pylori antibody in clinical laboratories in China

Background

This study aimed to investigate the implementation and quality control of the quantitative detection of serum Helicobacter pylori (H. pylori) antibody in clinical laboratories in China.

Methods

Online external quality assessment (EQA) questionnaires were distributed to the clinical laboratories by National Center for Clinical Laboratories (NCCL) of China. We collected information on the quantitative detection procedures of serum H. pylori antibody in clinical laboratories, including detection reagents, methods, instruments, calibrators, and internal quality control (IQC). We distributed quality control products to some select laboratories that conducted quantitative detection and analyzed the obtained test data. We evaluated the quantitative detection procedure based on the standard evaluation criteria set at a target value of ±30%.

Results

70.9% (146/206) of the laboratories conducted quantitative detection of H. pylori antibody; 29.1% (60/206) of the laboratories performed qualitative detection. Domestic reagents and matching calibrators accounted for more than 97.1% (200/206) of all reagents. Latex‐enhanced immunoturbidimetry was used in 89.7% (131/146) of the laboratories for quantitative determination, while the colloidal gold method was used in 66.7% (40/60) of the laboratories for qualitative determination. A total of 130 laboratories participated in the EQA; 123 completed the assessment, and the pass rate was 75.6% (93/123).

Conclusion

Clinical quantitative detection of serum H. pylori antibody is performed at a high rate in China. Thus, further studies on the specificity of commercial detection reagents are needed. EQAs are useful to monitor and improve the detection quality of H. pylori antibodies.

Current Helicobacter pylori Diagnostics

The high prevalence of Helicobacter pylori and the variety of gastroduodenal diseases caused by this pathogen necessitate the use of only accurate methods both for the primary diagnosis and for monitoring the eradication effectiveness. There is a broad spectrum of diagnostic methods available for detecting H. pylori. All methods can be classified as invasive or non-invasive. The need for upper endoscopy, different clinical circumstances, sensitivity and specificity, and accessibility defines the method chosen. This article reviews the advantages and disadvantages of the current options and novel developments in diagnostic tests for H. pylori detection. The progress in endoscopic modalities has made it possible not only to diagnose precancerous lesions and early gastric cancer but also to predict H. pylori infection in real time. The contribution of novel endoscopic evaluation technologies in the diagnosis of H. pylori such as visual endoscopy using blue laser imaging (BLI), linked color imaging (LCI), and magnifying endoscopy is discussed. Recent studies have demonstrated the capability of artificial intelligence to predict H. pylori status based on endoscopic images. Non-invasive diagnostic tests such as the urea breathing test and stool antigen test are recommended for primary diagnosis of H. pylori infection. Serology can be used for initial screening and epidemiological studies. The histology showed its value in detecting H. pylori and provided more information about the degree of gastric mucosa inflammation and precancerous lesions. Molecular methods are mainly used in detecting antibiotic resistance of H. pylori. Cultures from gastric biopsies are the gold standard and recommended for antibiotic susceptibility tests.

Pepsinogen and Serum IgG Detection Is a Valuable Diagnostic Method for Helicobacter pylori Infection in a Low-Prevalence Country: A Report from Sri Lanka

The use of serum anti-Helicobacter pylori IgG and pepsinogen (PG) detection as a diagnostic method was evaluated in Sri Lanka. Gastric biopsies were performed (353 patients), and the prevalence of H. pylori infection was 1.7% (culture) and 2.0% (histology). IgG serology testing showed an area under the curve (AUC) of 0.922 (cut-off, 2.95 U/mL; specificity, 91.56%; sensitivity, 88.89%). Histological evaluation showed mild atrophy (34.3%), moderate atrophy (1.7%), metaplasia (1.7%), chronic gastritis (6.2%), and normal tissue (56%). The PGI/PGII ratio was significantly higher in H. pylori-negative patients (p < 0.01). PGII and PGI/PGII levels were lower in patients with metaplasia than in those with normal mucosa (p = 0.049 and p < 0.001, respectively). The PGI/PGII ratio best discriminated metaplasia and moderate atrophy (AUC 0.88 and 0.76, respectively). PGI and PGII alone showed poor discriminative ability, especially in mild atrophy (0.55 and 0.53, respectively) and chronic gastritis (0.55 and 0.53, respectively). The best cut-off to discriminate metaplasia was 3.25 U/mL (95.19% specificity, 83.33% sensitivity). Anti-H. pylori IgG and PG assessment (ABC method) was performed (group B, 2.0%; group A, 92.1%). The new cut-off more accurately identified patients with metaplasia requiring follow-up (group B, 5.4%). Assessment of anti-H. pylori IgG and PG is valuable in countries with a low prevalence of H. pylori infection.

Serology Is More Sensitive Than Urea Breath Test or Stool Antigen for the Initial Diagnosis of Helicobacter pylori Gastritis When Compared With Histopathology

OBJECTIVES

To assess the concordance and performance characteristics of Helicobacter pylori laboratory tests compared with histopathology and to propose algorithms for the diagnosis of H pylori that minimize diagnostic error.

METHODS

H pylori diagnostics were reviewed from a 12-year period within a health system (2,560 cases). Analyses were performed to adjust diagnostic performance based on treatment and consensus histopathologic diagnoses among pathologists. Markers of access to care, including test cancellation frequency and turnaround time, were assessed. Costs and performance of candidate noninvasive testing algorithms were modeled as a function of disease prevalence.

RESULTS

Serum H pylori IgG demonstrated a higher sensitivity (0.94) than urea breath and stool antigen tests (0.64 and 0.61, respectively). Evidence of an advantage in access to care for serology included a lower cancellation rate. Interobserver variability was higher (κ = 0.34) among pathologists for cases with a discordant laboratory test than concordant cases (κ = 0.56). A model testing algorithm utilizing serology for first-time diagnoses minimizes diagnostic error.

CONCLUSIONS

Although H pylori serology has modestly lower specificity than other noninvasive tests, the superior sensitivity and negative predictive value in our population support its use as a noninvasive test to rule out H pylori infection. Reflexive testing with positive serology followed by either stool antigen or urea breath test may optimize diagnostic accuracy in low-prevalence populations.

Patients with dyspepsia have impaired mucosal integrity both in the duodenum and jejunum: in vivo assessment of small bowel mucosal integrity using baseline impedance

BACKGROUND

Recent studies reported that impaired proximal duodenal mucosa, assessed by duodenal biopsy, could play an important role in the development of dyspeptic symptoms. The aims of this study were (a) to develop a method to measure "in vivo" duodenal and jejunal baseline impedance (BI) and (b) to assess small bowel mucosal integrity in patients with functional dyspepsia (FD) and healthy controls (HC).

METHODS

We recruited 16 patients with FD and 15 HC. All subjects underwent ambulatory duodeno-jejunal manometry combined with impedance (HRM/Z), BI were determined by measuring impedance immediately after the passage of nocturnal migrating motor complex (MMC) phase IIIs.

RESULTS

The number of MMC phase IIIs in FD was significantly lower than that in HC (2.6 ± 1.4 vs 4.8 ± 1.7, p < 0.001). The BI in patients was significantly lower than that in HC in D1(164.2 ± 59.8 Ω in FD and 243.1 ± 40.5 Ω in HC, p = 0.0061), D2 (191.2 ± 34.1 and 256.5 ± 91.4 Ω, p = 0.01), D3 (214.0 ± 76.9 and 278.1 ± 45.3 Ω, p = 0.009), D4 (270.8 ± 54.2 and 351.8 ± 50.2 Ω, p < 0.001), and J1 (312.2 ± 55.4 and 379.3 ± 38.3 Ω, p = 0.001).

CONCLUSIONS

This is the first study reporting the duodenal and jejunal BI in vivo. The results have shown significantly lowered BI in the proximal small intestine in patients with FD compared to HC. Furthermore it suggests that measurements of small bowel BI could be used as a biomarker for diagnosis and follow up of patients with FD.

Is breath testing without 13C-labelled external urea able to detect Helicobacter pylori infection?

Helicobacter pylori (H. pylori) infection is the main cause of gastric inflammation and peptic ulcer disease. Diagnosis and treatment are important to prevent these outcomes. The diagnosis of H. pylori infection can be performed by non-invasive methods, such as ¹³C-urea breath test (¹³C-UBT). As endogenous urea is normally released to body cavities, we sought to investigate the usefulness of UBT without ¹³C-labelled external urea to detect H. pylori infection. The analysis was performed in a series of adult patients just before upper gastrointestinal endoscopy and biopsy to investigate dyspeptic symptoms. Breath samples were analyzed using isotope ratio mass spectrometry (IRMS). The natural variation of ¹³C and ¹⁸O isotopic abundance in the breath samples was also investigated. The results of the isotopic analysis were compared with the findings of the histopathological evaluation of gastric biopsies, which is the gold standard to detect H. pylori infection. No differences between patients with or without H. pylori infection could be detected by the isotope analysis of breath tests without ¹³C-urea. Therefore, our results showed that UBT without ¹³C-urea, analyzed by IRMS, was not useful to detect H. pylori infection in the study population.

Accurate Detection of Helicobacter pylori Antigen in Human Stool Specimens by Two Novel Immunoassays

Stool antigen tests are recommended for the diagnosis of Helicobacter pylori infection. Here, we compared two novel assays, i.e., one enzyme immunoassay (EIA) and one immunochromatography assay (ICA), with a chemiluminescence immunoassay (CLIA) that had previously been compared with rapid urease test, histology, and urea breath test. Two hundred sixty-six frozen stool samples with defined CLIA results (42 positives, 219 negatives, and 5 samples with borderline results) collected between January and May 2018 were thawed and immediately tested by EIA, ICA, and CLIA. In 248 samples with repeatedly positive/negative CLIA results, EIA and ICA were positive for 40 and 37 of 41 CLIA-positive samples and yielded negative results for 206 and 201 of 207 CLIA-negative samples, respectively. There was a high positive percent agreement (EIA, 97.6%; 95% confidence interval (95% CI), 86.3-100%; ICA, 90.2%; 95% CI, 76.9-96.7%), as well as a negative percent agreement between the assays (EIA, 99.5%; 95% CI, 97.0-100%; ICA, 97.1%; 95% CI, 93.7-98.8%). This was further supported by kappa values indicating very good agreement (CLIA vs. EIA, 0.971; CLIA vs. ICA, 0.857). In conclusion, both EIA and ICA comprise valuable assays for the detection of H. pylori antigen in stool samples.

The Diagnostic Tests for Detection of Helicobacter pylori Infection

Helicobacter pylori causes one of the most common infections in human populations. The role of this bacterium in chronic gastritis, gastric ulcer, gastric cancer, as well as extra-digestive diseases such as ischemic heart disease and chronic obstructive pulmonary diseases, is well known. Prevention and control of these diseases can occur by early diagnosis and eradication of H. pylori infection. At present, different methods have been established to detect H. pylori infection. The biopsy-based tests, which are known as invasive methods, such as rapid urease test and histology, have the highest specificity among the others. Similarly, culture of biopsy samples is used for diagnosis of H. pylori infection. It has a high specificity value, and also allows us to perform antibiotic sensitivity testing. On the contrary, polymerase chain reaction and other molecular methods have good sensitivity and specificity, and can be used for detection of H. pylori infection, its virulence factors, and eradication success after treatment. While serological tests are more appropriate for epidemiological studies, their main weakness for clinical use is low specificity. Overall, specificity and sensitivity, cost, usefulness, and limitation of tests should be considered for selection of detection methods of H. pylori in each country.

Diagnosis of Helicobacter pylori Using Invasive and Noninvasive Approaches

Helicobacter pylori (H. pylori) as gram-negative and spiral microorganism is responsible for colonization in the gastric microniche for more than 50% of world population. Recent studies have shown a critical role of H. pylori in the development of peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. Over the past decade, there has been a sharp interest to use noninvasive tests in diagnosis of the H. pylori infection. During the years after discovery by Marshall and Warren, it has been frequently declared that the rapid urease test (RUT) is one of the cheapest and rapid diagnostic approaches used in detecting the infection. Although the specificity and sensitivity are durable for this test, clinical experiences had shown that the ideal results are only achieved only if we take biopsies from both corpus and antrum at the same time. Given the diagnosis of the H. pylori in clinical samples, gastroenterologists are facing a long list of various molecular and nonmolecular tests. We need more in-depth researches and investigations to correctly generalize rapid and accurate molecular tests determining both bacterial identity and antibiotic resistance profile.

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.