Helicobacter pylori: A Contemporary Perspective on Pathogenesis, Diagnosis and Treatment Strategies

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the gastric mucosa and is associated with various gastrointestinal disorders. H. pylori is a pervasive pathogen, infecting nearly 50% of the world's population, and presents a substantial concern due to its link with gastric cancer, ranking as the third most common cause of global cancer-related mortality. This review article provides an updated and comprehensive overview of the current understanding of H. pylori infection, focusing on its pathogenesis, diagnosis, and treatment strategies. The intricate mechanisms underlying its pathogenesis, including the virulence factors and host interactions, are discussed in detail. The diagnostic methods, ranging from the traditional techniques to the advanced molecular approaches, are explored, highlighting their strengths and limitations. The evolving landscape of treatment strategies, including antibiotic regimens and emerging therapeutic approaches, is thoroughly examined. Through a critical synthesis of the recent research findings, this article offers valuable insights into the contemporary knowledge of Helicobacter pylori infection, guiding both clinicians and researchers toward effective management and future directions in combating this global health challenge.

The link between Helicobacter pylori infection and gallbladder and biliary tract diseases: A review

Helicobacter pylori is a gram-negative pathogen commonly associated with peptic ulcer disease and gastric cancer. H. pylori infection has also been reported in cholelithiasis, cholecystitis, gallbladder polyps, and biliary tract cancers. However, the association between H. pylori and gallbladder and biliary tract pathologies remains unclear due to the paucity of literature. In response to the current literature gap, we aim to review and provide an updated summary of the association between H. pylori with gallbladder and biliary tract diseases and its impact on their clinical management. Relevant peer-reviewed studies were retrieved from Medline, PubMed, Embase, and Cochrane databases. We found that H. pylori infection was associated with cholelithiasis, chronic cholecystitis, biliary tract cancer, primary sclerosing cholangitis, and primary biliary cholangitis but not with gallbladder polyps. While causal links have been reported, prospective longitudinal studies are required to conclude the association between H. pylori and gallbladder pathologies. Clinicians should be aware of the implications that H. pylori infection has on the management of these diseases.

Clinical Management of Patients with Gastric MALT Lymphoma: A Gastroenterologist's Point of View

Gastric mucosa-associated lymphoid tissue (MALT) lymphomas (GML) are non-Hodgkin lymphomas arising from the marginal zone of the lymphoid tissue of the stomach. They are usually induced by chronic infection with Helicobacter pylori (H. pylori); however, H. pylori-negative GML is of increasing incidence. The diagnosis of GML is based on histological examination of gastric biopsies, but the role of upper endoscopy is crucial since it is the first step in the diagnostic process and, with currently available novel endoscopic techniques, may even allow an in vivo diagnosis of GML per se. The treatment of GML, which is usually localized, always includes the eradication of H. pylori, which should be performed even in H. pylori-negative GML. In the case of GML persistence after eradication of the bacteria, low-dose radiotherapy may be proposed, while systemic treatments (immunochemotherapy) should be reserved for very rare disseminated cases. In GML patients, at diagnosis but even after complete remission, special attention must be paid to an increased risk of gastric adenocarcinoma, especially in the presence of associated gastric precancerous lesions (gastric atrophy and gastric intestinal metaplasia), which requires adequate endoscopic surveillance of these patients.

Gaita Örneklerinde Helicobacter pylori Antijen Pozitifliği ile İntestinal Parazit Birlikteliğinin Araştırılması

Aim: Helicobacter pylori and intestinal parasitic infections are commonly seen, especially in areas with low socioeconomic status and poor hygiene conditions. H. pylori and Giardia duodenalis can be commonly found in patients with upper gastrointestinal system complaints. It is thought that the urease activity of H. pylori may help intestinal parasites pass into the intestines without being affected by the acidic environment of the stomach. In this study, it was aimed to investigate the association of H. pylori and intestinal parasites (IP) in patients with gastrointestinal system complaints. Material and Method: A total of 408 patients, who were admitted to our hospital with gastrointestinal complaints between 2018 and 2020 and whose H. pylori rapid antigen test was studied simultaneously with intestinal parasite examination in the stool, were evaluated retrospectively. Results: Out of 408 patients whose stool samples were examined, one or more intestinal parasites were detected in 80 (19.6%), and H. pylori antigen test was positive in 65 (15.9%). While there was no statistically significant difference between H. pylori positivity and age groups, the rate of IP detection was found to be significantly higher in children aged 6-18 years. The most prevalent IP was Blastocystis sp. in 74 (18.1%) patients. Intestinal parasite and H. pylori antigen co-positivity in stool samples was detected in eight patients and it was not found statistically significant. Conclusion: H. pylori and intestinal parasites are common all over the world. The relationship between H. pylori and IP is still controversial, and more studies that are comprehensive are needed to understand the association of H. pylori and IP, especially in patients with upper gastrointestinal system complaints.

Overview of Helicobacter pylori Infection: Clinical Features, Treatment, and Nutritional Aspects

Helicobacter pylori (H. pylori) is a 0.5-1 µm wide, 2-4 µm long, short helical, S-shaped Gram-negative microorganism. It is mostly found in the pyloric region of the stomach and causes chronic gastric infection. It is estimated that these bacteria infect more than half of the world's population. The mode of transmission and infection of H. pylori is still not known exactly, but the faecal-oral and oral-oral routes via water or food consumption are thought to be a very common cause. In the last three decades, research interest has increased regarding the pathogenicity, microbial activity, genetic predisposition, and clinical treatments to understand the severity of gastric atrophy and gastric cancer caused by H. pylori. Studies have suggested a relationship between H. pylori infection and malabsorption of essential micronutrients, and noted that H. pylori infection may affect the prevalence of malnutrition in some risk groups. On the other hand, dietary factors may play a considerably important role in H. pylori infection, and it has been reported that an adequate and balanced diet, especially high fruit and vegetable consumption and low processed salty food consumption, has a protective effect against the outcomes of H. pylori infection. The present review provides an overview of all aspects of H. pylori infection, such as clinical features, treatment, and nutrition.

Detection of Helicobacter pylori in gastric cancer tissue through histopathology, immunohistochemistry and real-time reverse transcription-PCR

Aim: Helicobacter pylori is usually detected based on hematoxylin-eosin (H-E) features, but, immunohistochemistry (IHC) and real-time PCR (RT-PCR) are more precise in chronic-gastritis. We evaluated the relevance of these tests in Peruvian gastric cancer samples. Materials & methods: We performed and evaluated H-E, IHC staining and RT-PCR in 288 gastric tumors. Slides were independently evaluated by three pathologists. Results: H. pylori was detected in 167/287 through H-E, 140/288 through IHC and 175/288 through RT-PCR, and positive-status were associated (p < 0.001). H. pylori detection by H-E had a good concordance with IHC (kappa index = 0.632) but poor with RT-PCR (kappa index = 0.317). Higher median gene-copies were found in high H. pylori density through H-E or IHC (p < 0.001). Conclusion: H-E evaluation is accurate in gastric cancer, and IHC and RT-PCR can complement its results.

Droplet Digital PCR Detects Low-Density Infection in a Significant Proportion of Helicobacter Pylori-Negative Gastric Biopsies of Dyspeptic Patients

INTRODUCTION

Helicobacter pylori-infected individuals may present low-density infection, undetectable by conventional tests such as histology, rapid urease test, or urea breath test. Droplet digital polymerase chain reaction (ddPCR) is more sensitive than other polymerase chain reaction methods. We aimed to evaluate the ability of ddPCR to detect H. pylori infection in patients diagnosed as negative by conventional tests.

METHODS

Dyspeptic patients (n = 236) were tested for H. pylori by histology, urea breath test, and rapid urease test. Patients were classified as having 3 positive (n = 25, control group), 2 positive (n = 12), one positive (n = 41), or zero positive (n = 158) diagnostic tests. DNA was extracted from gastric biopsies. Triplicate ddPCR testing for each of the 16S rDNA, ureA, and vacA(s) genes was performed using a QX200 ddPCR system (Bio-Rad). A gene was considered positive when detected by at least 2 of 3 repeated ddPCRs. H. pylori positivity was defined as having 2 or more positive genes.

RESULTS

All the biopsies of the control patients were positive for all 3 16S rDNA, ureA, and vacA(s) genes. H. pylori infection was detected in 57 (36%), 22 (54%), and 9 (75%) patients with zero, 1, and 2 positive diagnostic tests, respectively. The density of infection was 5, 121, 599, and 3,133 copies of H. pylori genome equivalents for patients with zero, 1, and 2 of 3 positive test results and for the control group, respectively.

DISCUSSION

ddPCR detected low-density "occult" H. pylori infection in a significant proportion (36%) of patients diagnosed as negative by conventional methods. The number of conventional positive tests was related to the density of infection.

Value of CIM, CLO Test and Multiplex PCR for the Diagnosis of Helicobacter Pylori Infection Status in Patients with Gastritis and Gastric Ulcer

Objective:

To assess the value of Current Infection Marker (CIM) test, Campylobacter-Like Organism (CLO) test, and the multiplex polymerase chain reaction test (PCR) for the diagnosis of Helicobacter pylori (H. pylori) infection in a Vietnamese population.

Methods:

Targeted suitable patients were recruited. CIM test, CLO test and multiplex PCR were used to diagnose for H. pylori infection. Patients were considered positive for H. pylori when at least two of the three tests were positive. The performance of each of the three tests was compared to the H. pylori positive populations as defined.

Result:

Amongst 201 patients with a mean age of 40.5 (range, 18-74) years, there were 115 females and 86 males. Of the 201 patients, 107 (53.2%) were diagnosed as H. pylori positive according to the defined criteria. The positive patients obtained with CLO test, CIM test and multiplex PCR were 38.3%, 59.2% and 72.1%, correspondingly. The full performance of the three tests as highlighted in order as above were 85.07%, 83.08% and 81.09%, respectively. The positive rate of CLO test was the lowest, with 38.3% positive, but this method was the most accurate, with the accuracy of 85.07%. This suggested that CLO test has the highest specificity among the three. The sensitivity, specificity, positive, negative predictive values and accuracy of the CLO / CIM / multiplex PCR tests were 71.96% / 89.72% / 100%, 100% / 75.53% / 59.57%, 100% / 80.67% / 73.79%, 75.81% / 86.59% / 100%, and 85.07% / 83.08% / 81.09%, respectively.

Conclusion:

All the three methods have high accuracy for the diagnosis of H. pylori infection in the Vietnamese population with gastritis and gastric ulcers. These tests can be employed in the clinical settings for the Vietnamese population. CLO test should be used in combination with the other tests to reduce false-negative results.