Helicobacter infections with rare bacteria or minimal gastritis: Expecting the unexpected

Helicobacter pylori

Helicobacter pylori (H. pylori) is an important human pathogen etiologically associated with peptic ulcers and gastric cancer. The infection is present in approximately one-half of the world's population. Population-based H. pylori eradiation has confirmed that cure or prevention of the infection produces a marked reduction in gastric cancer and peptic ulcer disease. Antimicrobial therapy has become increasingly ineffective, and complexity and costs of antimicrobial therapy for infected individuals residing in and, immigrating from, the developing world combined with the cost of treatment for cancer make vaccine development a cost-effective alternative. Challenge studies allowed making a "go-no go" decision regarding vaccine effectiveness. We provide detailed protocols regarding challenge strain selection and administration as well as guidance regarding the clinical and laboratory tests used to confirm and monitor experimental infection. Experience shows that reliance of noninvasive methods led to the erroneous conclusion that some subjects were not infected. The current data suggests that histologic assessment of gastric mucosal biopsies may be one of the most sensitive and specific means of assessment of the presence of experimental infection as well as of successful H. pylori eradication. We recommend detailed recommendations for acquiring, processing, embedding, sectioning, and examining the gastric biopsies.

Establishment of a modified Kyoto classification scoring model and its significance in the diagnosis of Helicobacter pylori current infection

BACKGROUND AND AIMS

We aimed to establish a modified model of the Kyoto classification score and verify its accuracy for predicting Helicobacter pylori (HP) infection during endoscopy.

METHODS

Patients who underwent gastroscopy from June 2020 to March 2021 were included in this study. Atrophy, intestinal metaplasia, hypertrophy of the gastric fold, nodularity, diffuse redness, sticky mucus, spotty redness, xanthoma, map-like redness, fundic gland polyp, and regular arrangement of collecting venules (RAC) were recorded according to the Kyoto classification of gastritis. The HP infection status of participants was determined by a ¹³C breath test, anti-HP antibody, and histopathologic hematoxylin and eosin staining. The modified Kyoto classification scoring model was established based on univariate analysis and logistic regression analysis. The modified scoring model was used to judge the status of HP infection in patients undergoing gastroscopy from July to September 2021 and to evaluate the accuracy of the prediction.

RESULTS

Of 667 participants in the derivation dataset, 326 cases had HP infection and 341 cases did not. Atrophy, hypertrophy of the gastric fold, nodularity, diffuse redness, sticky mucus, and spotty redness were associated with HP current infection. Thus, a new scoring model, termed the modified Kyoto classification scoring model, was constructed that included atrophy, hypertrophy of the gastric fold, nodularity, diffuse redness, sticky mucus, spotty redness, fundic gland polyp, and RAC as indicators. To test the model, 808 subjects, including 251 HP-positive patients, comprised the validation dataset.

CONCLUSIONS

The modified Kyoto classification scoring model improved the accuracy of endoscopic determination of HP current infection and has clinical application potential in the Chinese population.

Real-time gastric juice analysis with EndoFaster for H. pylori diagnosis: a large, multicentre study

BACKGROUND

Helicobacter pylori infection is the main cause of the most frequent gastroduodenal diseases. Because its prevalence is decreasing in developed countries, gastric biopsies are negative in several patients. By measuring ammonium in the gastric juice, EndoFaster allows to exclude H. pylori infection during endoscopy. This study aimed to assess the accuracy of device versions working with either 6 ml or 3 ml of gastric juice.

STUDY DESIGN

This prospective study involved 12 endoscopic units. During endoscopy, EndoFaster testing was performed and standard five gastric biopsies were taken. The accuracy was calculated by considering histological assessment as the gold standard for H. pylori diagnosis.

RESULTS

Gastric juice analysis was attempted in 1279 patients, but it failed in 131 (15.5%) and in 10 (2.3%), with the 6 ml and the 3 ml device, respectively (P < 0.001). Overall, EndoFaster detected H. pylori infection with an 86.3% sensitivity, 83.3% specificity, 52.7% positive predictive value, 96.6% negative predictive value and 83.8% accuracy. The performance was not affected either by ongoing proton pump inhibitor therapy or a previous H. pylori eradication. No significant difference in accuracy emerged between the two versions of the device.

CONCLUSION

The novel version of the EndoFaster device operating with 3 ml gastric juice may be performed in virtually all patients, and it allows excluding H. pylori infection with a very high accuracy. Gastric biopsies can be avoided in a definite portion of cases without endoscopic lesions or other clinical indications.

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.

Quantification of Mucosal Eosinophils for the Histopathologic Diagnosis of Eosinophilic Gastritis and Duodenitis: A Primer for Practicing Pathologists

Eosinophilic gastrointestinal diseases, specifically eosinophilic gastritis and duodenitis, are chronic inflammatory conditions characterized by persistent gastrointestinal (GI) symptoms and elevated levels of activated eosinophils in the GI tract. Both clinical and endoscopic findings are nonspecific, no clinical or histopathologic diagnostic guidelines are published, and disease awareness is low, both among clinicians and amongst pathologists, who tend to overlook mild or moderate increases in the density of eosinophils in GI biopsy specimens. Yet, evaluating and, at times, counting eosinophils in GI biopsies may have important clinical implications: the numbers of tissue eosinophils correlate with clinical manifestations, can be used as determinants of effective management, and are used to assess the effects of treatment. A most persuasive argument for providing a count rather than a value judgment is that patients read reports, understand numbers, and use them to help to understand the course of their disease. The objective of this primer is to provide pathologists with the tools to incorporate a quantitative assessment of eosinophilia in the diagnosis of gastric and duodenal biopsy specimens and to develop a systematic approach to their evaluation, counting, and reporting. To achieve this aim, we present our general approach to the biopsy (where to count), followed by details on the characteristics of a countable eosinophil (what to count), and provide with a set of suggestions on the counting methods (how to count). We conclude with suggestions on how to report GI tissue eosinophilia in a manner that alerts clinicians and prompts pertinent management steps.

Evolution of Diagnostic Methods for Helicobacter pylori Infections: From Traditional Tests to High Technology, Advanced Sensitivity and Discrimination Tools

Rapid diagnosis and treatment application in the early stages of H. pylori infection plays an important part in inhibiting the transmission of this infection as this bacterium is involved in various gastric pathologies such as gastritis, gastro-duodenal ulcer, and even gastric neoplasia. This review is devoted to a quick overview of conventional and advanced detection techniques successfully applied to the detection of H. pylori in the context of a compelling need to upgrade the standards of the diagnostic methods which are currently being used. Selecting the best diagnostic method implies evaluating different features, the use of one or another test depending on accessibility, laboratories equipment, and the clinical conditions of patients. This paper aims to expose the diagnosis methods for H. pylori that are currently available, highlighting their assets and limitations. The perspectives and the advantages of nanotechnology along with the concept of nano(bio)sensors and the development of lab-on-chip devices as advanced tools for H. pylori detection, differentiation, and discrimination is also presented, by emphasizing multiple advantages: simple, fast, cost-effective, portable, miniaturized, small volume of samples required, highly sensitive, and selective. It is generally accepted that the development of intelligent sensors will completely revolutionize the acquisition procedure and medical decision in the framework of smart healthcare monitoring systems.

Diagnosis and Treatment of Helicobacter pylori Infection

The last 5 years have seen major shifts in defining whom to test and how to treat Helicobacter pylori infection. Peptic ulcer has changed from a chronic disease to a one-off condition, and countries with a high incidence of gastric cancer have begun implementing population-wide screening and treatment. A proactive approach to testing and treatment of H. pylori is now recommended, including outreach to family members of individuals diagnosed with active infection as well as high-risk local populations such as immigrants from high-risk countries. Increasing antimicrobial resistance has resulted in an overall decline in treatment success, causing a rethinking of the approach to development of treatment guidelines as well as the need to adopt the principles of antibiotic usage and antimicrobial stewardship. Required changes include abandoning empiric use of clarithromycin, metronidazole, and levofloxacin triple therapies. Here, we discuss these transformations and give guidance regarding testing and use of therapies that are effective when given empirically.

What Is New in Helicobacter pylori Diagnosis. An Overview

Helicobacter pylori infection remains one of the most prevalent infections worldwide, especially in low-resource countries, and the major risk factor for peptic ulcer and gastric cancer. The “test-and-treat” strategy is recommended by several guidelines and consensus. The choice of testing method is based on patient age, presence of alarm signs and/or symptoms, use of non-steroidal anti-inflammatory drugs, as well as local availability, test reliability, and cost. Culture is the gold standard to detect H. pylori and, possibly, to perform susceptibility testing, however, it requires upper endoscopy and dedicated labs. Recent advances in molecular biology have provided new strategies in detecting infection and antimicrobial resistance without invasive tests. In this review we attempt to offer a comprehensive panorama on the new diagnostic tools and their potential use in clinical settings, in order to accomplish specific recommendations.

Real-time EndoFaster improves Helicobacter pylori detection in chronic active gastritis

Helicobacter pylori is the most frequent cause of chronic active gastritis (CAG), namely the first step for gastric cancer development. When infection is not detected at histology, another test is advised. EndoFaster is novel device that reveal the presence of H. pylori by determining ammonium concentration in the gastric juice during endoscopy. We evaluated whether this test may improve etiological diagnosis in CAG patients. In 595 consecutive patients who underwent upper endoscopy gastric juice was analysed with EndoFaster and standard biopsies were taken. CAG with typical bacteria was detected in 102 (17.1%) patients, and CAG without H. pylori was found in 36 (6.3%) cases. EndoFaster detected the infection in 22 (61.1%) of these patients. Neither ongoing proton pump inhibitor therapy nor previous eradication therapy affect the test accuracy. By using EndoFaster, another test to search for the infection in H. pylori-negative CAG patients may be avoided in more than 60% of cases, impacting on both patients discomfort and health resources use.

An Update on the Role of Immunohistochemistry in the Evaluation of Gastrointestinal Tract Disorders

As in other organ systems, immunohistochemistry (IHC) serves as an ancillary diagnostic tool for a wide variety of neoplastic and non-neoplastic disorders, including infections, work-up of inflammatory conditions, and subtyping neoplasms of the gastrointestinal (GI) tract. In addition, IHC is also used to detect a variety of prognostic and predictive molecular biomarkers for carcinomas of the GI tract. The purpose of this review is to highlight the use of IHC in common diagnostic scenarios throughout the tubular GI tract. The clinical indication and guidelines for performing IHC for detecting Helicobacter pylori is discussed along with role of gastrin and neuroendocrine markers in the diagnosis of autoimmune metaplastic atrophic gastritis. The major portion of this review discusses the use of IHC in the diagnostic workup of malignant neoplasms of the GI tract, such as adenocarcinoma versus squamous cell carcinoma, workup of poorly differentiated malignant neoplasms, and evaluation of uncommon gastric neoplasms (alpha-feto protein-producing carcinomas) and switch/sucrose-nonfermenting complex-deficient carcinomas. Lastly, localization of neuroendocrine tumors of unknown origin to aid clinical management, as well as HPV-driven anal neoplasia and IHC in the workup of basaloid anal neoplasms are also reviewed.

Contribution of genetic amplification by PCR for the diagnosis of Helicobacter pylori infection in patients receiving proton pump inhibitors

Background

Helicobacter pylori detection by standard methods may be altered by proton pump inhibitor (PPI) use. However, some patients cannot or should not interrupt PPI use before undergoing testing for H. pylori. Polymerase chain reaction (PCR) could allow more reliable H. pylori detection even in patients taking PPIs.

Objective

The aim of our study is to compare the H. pylori infection diagnostic value of histological examination without and with immunohistochemical staining, bacterial culture and PCR, in PPI-treated vs untreated patients.

Methods

Patients undergoing a gastric endoscopy for upper digestive symptoms were included. Gastric biopsy samples were obtained. The impact of taking PPI on the diagnostic performance of the different methods was studied. PCR results were confirmed by sequencing the glmM gene.

Results

A total of 497 patients were included, of whom 192 were H. pylori positive. Fifty-two patients received PPIs during the 14 days preceding the endoscopy while 140 did not. All methods had lower sensitivity than PCR, in all cases (PPI treatment or not). PPI use did not change significantly the methods' sensitivities.

Conclusion

The PCR method showed the best performance for the detection of H. pylori in gastric samples, whether or not patients received previous PPI treatment. This diagnosis test could become a new gold-standard test, especially in patients undergoing PPI treatment.

Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity

BACKGROUND

Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP).

MATERIALS AND METHODS

We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations.

RESULTS

Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings.

CONCLUSIONS

We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP.

Routine Anti-Helicobacter Immunohistochemical Staining is Significantly Superior to Reflex Staining Protocols for the Detection of Helicobacter in Gastric Biopsy Specimens

BACKGROUND

The role of special stains in the detection of H. pylori is controversial; some pathologists claim that hematoxylin and eosin staining alone is adequate to detect bacteria, while others maintain that immunohistochemical staining must be used on all gastric biopsies. This study was designed to test the hypothesis that hematoxylin and eosin and histochemical special stains have similar sensitivity and that immunohistochemical staining only marginally enhances the detection rate of the organisms.

MATERIALS AND METHODS

Records of all gastric biopsies examined in a large pathology laboratory between January 1, 2010 and December 31, 2014 were extracted and stratified according to the stain used for the detection of Helicobacter (1. hematoxylin and eosin only; 2. Upfront HP Blue; 3. Upfront HP Blue including reflex immunohistochemistry; 4. Upfront anti-Helicobacter immunohistochemical staining.

RESULTS

Gastric biopsies from 794,859 endoscopies obtained from 622,945 unique patients were analyzed. The basic demographics of the patients in different staining groups were identical. A total of 56,955 gastric biopsy sets were stained with histochemical stains only, and 731,193 with anti-Helicobacter immunohistochemical stain; in 4409 of these, an immunohistochemical stain was also performed. In 2302 cases, only hematoxylin and eosin were performed. In this latter group, 7.0% of patients were Helicobacter-positive; in the upfront HP Blue, the prevalence was 7.8%, whereas patients with upfront immunohistochemistry had a prevalence of 10.2% (p < .0001, compared to hematoxylin and eosin only).

CONCLUSIONS

There was a dramatic improvement in detection of H. pylori infection through the use of upfront immunohistochemical stains. Therefore, we contend that the routine use of IHC for all gastric biopsies is an appropriate protocol to ensure that every patient gets the right answer.

A Strategy for Helicobacter Immunohistochemistry Utilization in Pediatric Practice: Insights From Morphologic and Cost-Benefit Analyses

OBJECTIVES

Recent studies in adults have examined the utility of immunohistochemistry (IHC) in detecting Helicobacter in gastric biopsy specimens and reached differing conclusions. Dedicated cost-benefit analysis of Helicobacter IHC in pediatric gastric biopsy specimens has not been performed.

METHODS

From 1,955 pediatric gastric biopsies in a 1-year period, we identified 63 Helicobacter -positive and 120 Helicobacter -negative biopsy specimens. All cases were scored according to the Updated Sydney System for the severity of inflammation.

RESULTS

We observed that pediatric Helicobacter infection was significantly associated with germinal center formation, active inflammation, oxyntic mucosa with moderate to severe chronic inflammation, and antral mucosa with any chronic inflammation, exclusive of mild and superficial chronic inflammation. At least one associated pattern was seen in each Helicobacter -positive biopsy specimen. In comparison with adults, pediatric Helicobacter -positive biopsy specimens are more likely to lack acute inflammation and more likely to show moderate to marked chronic inflammation.

CONCLUSIONS

We recommend performing Helicobacter IHC on pediatric gastric biopsy specimens with any of the above inflammatory patterns. This approach can sensitively identify pediatric patients with Helicobacter gastritis, limit IHC staining to approximately 30% of all gastric biopsy specimens, and reduce costs by up to $55,306.90 per 1,000 biopsy specimens.

Diagnostic of Helicobacter pylori infection

There is progress in endoscopy techniques. While it is not yet possible to detect Helicobacter pylori directly in the stomach, it becomes easier to detect the mucosal changes induced by the bacteria. Some small changes can also increase the sensitivity of the invasive tests, for example culture or histology, but the wide use of proton-pump inhibitors has a negative impact on these tests. Only molecular methods are able to detect a limited load of bacteria, especially by using real-time PCR but also with new methods, for example dual-priming oligonucleotide-based PCR, loop-medicated isothermal amplification, droplet-digital PCR or a multiple genetic analysis system. Among the noninvasive tests, urea breath test remains a test of major interest, while there are attempts to develop an ammonia breath test and other nanosensor devices. A new antigen stool test, a chemoluminescence immunoassay using the LIAISON apparatus has also been tested for the first time with success. Despite its limitations, serology remains the most popular test to detect H. pylori antibodies. It also allows pepsinogen dosage which is of interest for detecting atrophy.

Helicobacter-negative gastritis: polymerase chain reaction for Helicobacter DNA is a valuable tool to elucidate the diagnosis

BACKGROUND

Helicobacter-negative gastritis has been increasingly reported. Molecular techniques as the polymerase chain reaction (PCR) may detect bacterial DNA in histologically negative gastritis.

AIM

To evaluate of Helicobacter PCR in gastric biopsies for the daily diagnostics of Helicobacter-negative gastritis.

METHODS

Over a 5-year period, routine biopsies with chronic gastritis reminiscent of Helicobacter infection, but negative by histology, were tested by using a H. pylori specific PCR. Subsequently, PCR-negative samples were re-evaluated using PCR for other Helicobacter species.

RESULTS

Of the 9184 gastric biopsies, 339 (3.7%) with histological-negative gastritis and adequate material were forwarded to PCR analysis for H. pylori and 146 (43.1%) revealed a positive result. In 193 H. pylori DNA-negative biopsies, re-analysis using PCR primers for other Helicobacter species, revealed further 23 (11.9%) positive biopsies, including 4 (2.1%) biopsies with H. heilmannii sensu lato. PCR-positive biopsies showed a higher overall inflammatory score, more lymphoid follicles/aggregates and neutrophils (P < 0.05). No Helicobacter DNA was found in control biopsies of 48 patients with neither primer set (P < 0.0001). In 274 patients with an endoscopic description, detection of H. pylori DNA was associated with ulcers and erosions (P < 0.01). Over all, in 339 histologically-negative gastric biopsies, Helicobacter DNA was detected in 169 (49.9%) samples with at least one primer set.

CONCLUSION

Molecular testing offers a sensitive and specific diagnosis to a selected group of patients, in whom adequate searches for bacteria by conventional histology have resulted in the unsatisfactory diagnosis of H. pylori-negative gastritis.