Application of 16S rRNA gene sequencing in Helicobacter pylori detection

Exploring the presence of oral bacteria in non-oral sites of patients with cardiovascular diseases using whole metagenomic data

Cardiovascular diseases (CVDs) encompass various conditions affecting the heart and its blood vessels and are often linked with oral microbes. Our data analysis aimed to identify oral bacteria from other non-oral sites (i.e., gut, arterial plaque and cultured blood) that could be linked with CVDs. Taxonomic profiling identified bacteria to the species level and compared with the Human Oral Microbiome Database (HOMD). The oral bacteria in the gut, cultured blood and arterial plaque samples were catalogued, with their average frequency calculated for each sample. Additionally, data were filtered by comparison with the Human Microbiome Project (HMP) database. We identified 17,243 microbial species, of which 410 were present in the HOMD database and further denominated as "oral", and were found in at least one gut sample, but only 221 and 169 species were identified in the cultured blood and plaque samples, respectively. Of the 410 species, 153 were present solely in oral-associated environments after comparison with the HMP database, irrespective of their presence in other body sites. Our results suggest a potential connection between the presence of specific species of oral bacterial and occurrence of CVDs. Detecting these oral bacterial species in non-oral sites of patients with CVDs could help uncover the link between oral health and general health, including cardiovascular conditions via bacterial translocation.

Advances on diagnosis of Helicobacter pylori infections

The association of Helicobacter pylori to several gastric diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer, and its high prevalence worldwide, raised the necessity to use methods for a proper and fast diagnosis and monitoring the pathogen eradication. Available diagnostic methods can be classified as invasive or non-invasive, and the selection of the best relies on the clinical condition of the patient, as well as on the sensitivity, specificity, and accessibility of the diagnostic test. This review summarises all diagnostic methods currently available, including the invasive methods: endoscopy, histology, culture, and molecular methods, and the rapid urease test (RUT), as well as the non-invasive methods urea breath test (UBT), serological assays, biosensors, and microfluidic devices and the stool antigen test (SAT). Moreover, it lists the diagnostic advantages and limitations, as well as the main advances for each methodology. In the end, research on the development of new diagnostic methods, such as bacteriophage-based H. pylori diagnostic tools, is also discussed.

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.

Errors in the diagnosis and treatment of <i>Helicobacter pylori</i> infection: in anticipation of new conciliation documents

The high prevalence of H. pylori and diseases caused by this infection determine the relevance of discussing the problems of its diagnosis and treatment on the eve of the emergence of new international and domestic agreements. Studies published in recent years, including articles on the materials of the European Registry on the management of Helicobacter pylori infection (Hp-EuReg), provide a rich background for the analysis of errors in diagnosis and treatment of this infection, and the development of approaches to optimize clinical practice.

Errors in the diagnosis and treatment of <i>Helicobacter pylori</i> infection: in anticipation of new conciliation documents

The high prevalence of H. pylori and diseases caused by this infection determine the relevance of discussing the problems of its diagnosis and treatment on the eve of the emergence of new international and domestic agreements. Studies published in recent years, including articles on the materials of the European Registry on the management of Helicobacter pylori infection (Hp-EuReg), provide a rich background for the analysis of errors in diagnosis and treatment of this infection, and the development of approaches to optimize clinical practice.

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.

Advantage of 16S rRNA amplicon sequencing in Helicobacter pylori diagnosis

BACKGROUND

16S rRNA amplicon sequencing is an accurate method of detecting microbial infection without culture. It is unclear if sequencing has additional benefits over routine diagnostic methods for Helicobacter pylori testing.

METHODS

We enrolled Mongolian volunteers with dyspepsia. Using routine diagnostic methods, positive H. pylori was defined as positive results on histology/immunohistochemistry, culture, rapid urease test, or serology; negative H. pylori was defined by negative results from all these tests. We performed 16S rRNA sequencing on gastric biopsy specimens and calculated cutoffs for operational taxonomic units (OTUs) and relative abundance (RA) to define positive results using ROC curves.

RESULTS

We examined 161 individuals with a mean age of 43.6 years, and 64.6% were women. Using routine diagnostic methods, 122 (75.8%) participants were H. pylori positive, the sensitivity and specificity for 16S rRNA sequencing were 94.3% and 82.1% or 93.4% and 82.1% when cutoff values were set to 1113 (OTU number) or 4.4% RA, respectively (both p < .001). When combining the validated values, the concordance rate was high (91.1%); however, 16S rRNA sequencing had additional positive yield in 9 cases (5.6%) compared with routine diagnostic methods, and much greater additional positive yield compared to histopathology/IHC, culture, RUT, serology separately with 12 (7.4%), 37 (23.0%) and 43 (26.7%).

CONCLUSION

16S rRNA amplicon sequencing detects potentially important proportion of H. pylori-positive cases that test negative with routine diagnostic methods. The quantitative number of H. pylori can help to understand how it can be changing by diseases and RA give opportunity to understand how H. pylori communicate with other microbiota.

Helicobacter pylori Outer Membrane Vesicles and Extracellular Vesicles from Helicobacter pylori-Infected Cells in Gastric Disease Development

Extracellular vesicles (EVs) are cell-derived vesicles important in intercellular communication that play an essential role in host-pathogen interactions, spreading pathogen-derived as well as host-derived molecules during infection. Pathogens can induce changes in the composition of EVs derived from the infected cells and use them to manipulate their microenvironment and, for instance, modulate innate and adaptive inflammatory immune responses, both in a stimulatory or suppressive manner. Gastric cancer is one of the leading causes of cancer-related deaths worldwide and infection with Helicobacter pylori (H. pylori) is considered the main risk factor for developing this disease, which is characterized by a strong inflammatory component. EVs released by host cells infected with H. pylori contribute significantly to inflammation, and in doing so promote the development of disease. Additionally, H. pylori liberates vesicles, called outer membrane vesicles (H. pylori-OMVs), which contribute to atrophia and cell transformation in the gastric epithelium. In this review, the participation of both EVs from cells infected with H. pylori and H. pylori-OMVs associated with the development of gastric cancer will be discussed. By deciphering which functions of these external vesicles during H. pylori infection benefit the host or the pathogen, novel treatment strategies may become available to prevent disease.

Review: Diagnosis of Helicobacter pylori infection

New imaging techniques are still the topic of many evaluations for both the diagnosis of Helicobacter pylori gastritis and the detection of early gastric cancer. Concerning invasive tests, there were studies on the reuse of the rapid urease test material for other tests, and a novel fluorescent method to be used for histology but with limited sensitivity. Progress occurred essentially in the molecular methods area, especially next-generation sequencing which is applied to detect both H pylori and the mutations associated with antibiotic resistance. For non-invasive tests, a few studies have been published on the validity of breath collection bags, the shortening of the testing time, the performance of different analysers or the added value of citric acid in the protocol. The accuracy of serological immunochromatographic tests is also improving. Multiplex serology detecting antibodies to certain proteins allows confirmation of a current infection. Dried blood spots can be used to collect and store blood without a loss of accuracy. Finally, the serum antibody titer can be useful in predicting the risk of gastric cancer. Several stool antigen tests were evaluated with good results, and a novel test using immunomagnetic beads coated with monoclonal antibodies is potentially interesting. PCR detection in stools can also be effective but needs an efficient DNA extraction method. The use of easyMAG^® (bioMérieux) combined with Amplidiag® H pylori + ClariR (Mobidiag) appears to be powerful.