Chronic inactive gastritis and coccoid Helicobacter pylori in patients treated for gastroesophageal reflux disease or with H pylori eradication therapy

Rebound of Reflux-Related Symptoms After Helicobacter pylori Eradication in Patients With Gastroesophageal Reflux Disease: A Prospective Randomized Study

BACKGROUND/PURPOSE

We aimed to assess the effects of Helicobacter pylori (H. pylori) eradication on the rebound of reflux-related symptoms among gastroesophageal reflux disease (GERD) patients.

METHODS

This prospective randomized study recruited patients with typical reflux symptoms and reflux esophagitis on esophagogastroduodenoscopy (NCT02934152). Patients positive for H. pylori via a urea breath test (UBT) were randomly assigned to receive bacterial eradication with triple therapy for 2 weeks either before or after proton-pump inhibitor (PPI) treatment for 4 weeks. Follow-up was implemented with serial GerdQ evaluation and a subsequent UBT. The primary outcome was the incidence rates of symptom rebound between patients with and without H. pylori infection. The secondary outcomes included the severity of symptom rebound, incidence rates of symptom rebound, and successful eradication rates between the early and late eradication groups.

RESULTS

A total of 248 patients were enrolled, of whom 107 (43.1%) tested positive for H. pylori infection. All patients with and without concurrent H. pylori infection had significant symptom improvement over the entire treatment. Patients with H. pylori infection had significantly lower rates of symptom rebound (19.8% vs. 34.2%, p = 0.034) and rebound severity (1.8 ± 0.7 vs. 2.8 ± 1.6, p = 0.031) 4 weeks after eradication and PPI treatment than those without. The incidence rates of symptom rebound and successful eradication rates were not significantly different between the early and late eradication groups.

CONCLUSIONS

GERD patients with concurrent H. pylori infection were less susceptible to symptom rebound after H. pylori eradication compared to those without.

TRIAL REGISTRATION

ClinicalTrial.gov (NCT02934152).

Pathohistological Changes in the Gastric Mucosa in Correlation with the Immunohistochemically Detected Spiral and Coccoid Forms of Helicobacter pylori

BACKGROUND

The coccoid form of Helicobacter pylori (H. pylori) is resistant to antibiotics. There are only a few studies that have analyzed the frequency of coccoid H. pylori in patients with gastritis. The aim of this work was to examine the correlation between the H. pylori form and the pathohistological characteristics of the stomach in patients with gastritis.

MATERIALS AND METHODS

This research was cross-sectional and focused on the gastric mucosa samples of 397 patients from one general hospital in Croatia. Two independent pathologists analyzed the samples regarding the pathohistological characteristics and the form of H. pylori.

RESULTS

There was a statistically significant difference in the gender of patients with H. pylori gastritis. Only the coccoid form of H. pylori was present in 9.6% of patients. There was a statistically significant difference in the frequency of a certain form of the bacterium depending on its localization in the stomach. The intensity of the bacterium was low in the samples where only the coccoid or spiral form was described. In cases of infection in the antrum, premalignant lesions and the coccoid form of H. pylori were more often present.

CONCLUSION

In the diagnosis of H. pylori infection, the determination of the form of the bacterium via immunohistochemistry should be included to increase the rate of eradication therapy and reduce the incidence of gastric malignancy.

Analysis of Helicobacter pylori resistance in patients with different gastric diseases

Helicobacter pylori (H. pylori) resistance is the most important risk factor for eradication failure. However, in most regions, antibiotic resistance rates of H. pylori in patients with different types of gastric mucosal lesions are still unclear. An 8-year clinical retrospective cohort study involving 2847 patients was performed. In this study, we first summarized and compared the resistance status of H. pylori in different years, ages, sexes, and gastric diseases. The resistance profiles of amoxicillin (AMX), clarithromycin (CLR), levofloxacin (LVX) and furazolidone (FR) and their changing trends in the clinic were described. Then, multiple antibiotic resistance in different gastric diseases and years were described and compared. The relationship between proton pump inhibitor (PPI) medication history and antibiotic resistance in H. pylori was also explored. Finally, an antibiotic resistance risk model was constructed for clinical resistance risk prediction. The overall resistance rates of AMX, CLR, LVX and FR in gastric diseases were 8.18%, 38.11%, 43.98%, and 13.73%, respectively. The mono resistance, double resistance, triple resistance, and quadruple resistance rates were 30.17%, 25.96%, 6.46%, and 0.63%, respectively. Compared with the period from 2014 to 2016, the rates of mono-resistance and multiple resistance all showed relatively downward trends in the past 5 years. Factors including age, sex, type of gastric lesions and recent PPI treatment history are associated with the antibiotic resistance rate of H. pylori. Atrophic gastritis is an important clinical feature of high-risk antibiotic resistance in H. pylori-infected patients. Patients with atrophic gastritis have higher risk of resistant strains infection. In this study, our data provide the association between antibiotic resistance of H. pylori and gastritis pattern, which indicate the higher risk of resistant strain infection if the patients with atrophic gastritis, PPI history and older age.

Retrospective analysis of discordant results between histology and other clinical diagnostic tests on helicobacter pylori infection

BACKGROUND

A reliable test is essential for diagnosing Helicobacter pylori (H. pylori) infection, and crucial for managing H. pylori-related diseases. Serving as an excellent method for detecting H. pylori infection, histologic examination is a test that clinicians heavily rely on, especially when complemented with immunohistochemistry (IHC). Additionally, other diagnostic tests for H. pylori, such as the rapid urease test (CLO test) and stool antigen test (SA), are also highly sensitive and specific. Typically, the results of histology and other tests align with each other. However, on rare occasions, discrepancy between histopathology and other H. pylori diagnostic tests occurs.

AIM

To investigate the discordance between histology and other H. pylori tests, the underlying causes, and the impact on clinical management.

METHODS

Pathology reports of gastric biopsies were retrieved spanning August 2013 and July 2018. Reports were included in the study only if there were other H. pylori tests within seven days of the biopsy. These additional tests include CLO test, SA, and H. pylori culture. Concordance between histopathology and other tests was determined based on the consistency of results. In instances where histology results were negative while other tests were positive, the slides were retrieved for re-assessment, and the clinical chart was reviewed.

RESULTS

Of 1396 pathology reports were identified, each accompanied by one additional H. pylori test. The concordance rates in detecting H. pylori infection between biopsy and other tests did not exhibit significant differences based on the number of biopsy fragments. 117 discrepant cases were identified. Only 20 cases (9 with CLO test and 11 with SA) had negative biopsy but positive results in other tests. Four cases initially stained with Warthin-Starry turned out to be positive for H. pylori with subsequent IHC staining. Among the remaining 16 true discrepant cases, 10 patients were on proton pump inhibitors before the biopsy and/or other tests. Most patients underwent treatment, except for two who were untreated, and two patients who were lost to follow-up.

CONCLUSION

There are rare discrepant cases with negative biopsy but positive in SA or CLO test. Various factors may contribute to this inconsistency. Most patients in such cases had undergone treatment.

Improving the detection of Helicobacter pylori in biopsies of chronic gastritis: a comparative analysis of H&E, methylene blue, Warthin-Starry, immunohistochemistry, and quantum dots immunohistochemistry

Objectives

The objective of the study was to compare the consistency of various staining methods, including H&E, Methylene Blue, Warthin-Starry (W-S), Immunohistochemistry (IHC) and Quantum dots immunohistochemistry (QDs-IHC), in detecting Helicobacter pylori (HP) in cases of mild, moderate and severe chronic gastritis.

Methods

Biopsy samples were obtained from 225 patients with chronic gastritis at the Department of Pathology, Yichang Central People's Hospital between January 2019 and October 2019. The presence of HP was detected using H&E, Methylene Blue, W-S, IHC, and QDs-IHC.

Results

The positive rates for HP detection using H&E, Methylene Blue, W-S, IHC, and QDs-IHC were 42.22%, 51.11%, 53.78%, 59.11%, and 58.67%, respectively. In cases of mild chronic gastritis, the consistency of test results between H&E, Methylene Blue, W-S, and QDs-IHC with IHC were Kappa=0.196, P=0.033, Kappa=0.706, P<0.001, Kappa=0.717, P<0.001, and Kappa=0.968, P<0.001, respectively. Similarly, in cases of moderate chronic gastritis, Kappa values between H&E, Methylene Blue, W-S, and QDs-IHC with IHC were 0.356, P<0.001, 0.655, P<0.001, 0.741, P<0.001, and 0.946, P<0.001, respectively. For cases of severe chronic gastritis, the Kappa values between the staining methods and IHC were 0.271, P=0.037, 0.421, P=0.002, 0.621, P<0.001, and 1, P< 0.001, respectively.

Conclusion

The study showed that the positivity rate of IHC was significantly higher than that of H&E, Methylene Blue, and W-S in detecting HP infection in chronic gastritis cases. In terms of consistency with IHC, QDs-IHC was the most reliable staining method across all severity grades, while the agreement between H&E and IHC was poor, and that between Methylene Blue and W-S with IHC was average. Pathology departments may choose the most appropriate staining method based on their specific needs, considering the staining time, contrast, and cost of each method.

A peptide of a type I toxin-antitoxin system induces Helicobacter pylori morphological transformation from spiral shape to coccoids

Toxin-antitoxin systems are found in many bacterial chromosomes and plasmids with roles ranging from plasmid stabilization to biofilm formation and persistence. In these systems, the expression/activity of the toxin is counteracted by an antitoxin, which, in type I systems, is an antisense RNA. While the regulatory mechanisms of these systems are mostly well defined, the toxins' biological activity and expression conditions are less understood. Here, these questions were investigated for a type I toxin-antitoxin system (AapA1-IsoA1) expressed from the chromosome of the human pathogen Helicobacter pylori We show that expression of the AapA1 toxin in H. pylori causes growth arrest associated with rapid morphological transformation from spiral-shaped bacteria to round coccoid cells. Coccoids are observed in patients and during in vitro growth as a response to different stress conditions. The AapA1 toxin, first molecular effector of coccoids to be identified, targets H. pylori inner membrane without disrupting it, as visualized by cryoelectron microscopy. The peptidoglycan composition of coccoids is modified with respect to spiral bacteria. No major changes in membrane potential or adenosine 5'-triphosphate (ATP) concentration result from AapA1 expression, suggesting coccoid viability. Single-cell live microscopy tracking the shape conversion suggests a possible association of this process with cell elongation/division interference. Oxidative stress induces coccoid formation and is associated with repression of the antitoxin promoter and enhanced processing of its transcript, leading to an imbalance in favor of AapA1 toxin expression. Our data support the hypothesis of viable coccoids with characteristics of dormant bacteria that might be important in H. pylori infections refractory to treatment.

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.

The Puzzle of Coccoid Forms of Helicobacter pylori: Beyond Basic Science

Helicobacter pylori (H. pylori) may enter a non-replicative, non-culturable, low metabolically active state, the so-called coccoid form, to survive in extreme environmental conditions. Since coccoid forms are not susceptible to antibiotics, they could represent a cause of therapy failure even in the absence of antibiotic resistance, i.e., relapse within one year. Furthermore, coccoid forms may colonize and infect the gastric mucosa in animal models and induce specific antibodies in animals and humans. Their detection is hard, since they are not culturable. Techniques, such as electron microscopy, polymerase chain reaction, loop-mediated isothermal amplification, flow cytometry and metagenomics, are promising even if current evidence is limited. Among the options for the treatment, some strategies have been suggested, such as a very high proton pump inhibitor dose, high-dose dual therapy, N-acetycysteine, linolenic acid and vonoprazan. These clinical, diagnostic and therapeutic uncertainties will represent fascinating challenges in the future.

Transformation of Helicobacter pylori into Coccoid Forms as a Challenge for Research Determining Activity of Antimicrobial Substances

Morphological variability is one of the phenotypic features related to adaptation of microorganisms to stressful environmental conditions and increased tolerance to antimicrobial substances. Helicobacter pylori, a gastric mucosal pathogen, is characterized by a high heterogeneity and an ability to transform from a spiral to a coccoid form. The presence of the coccoid form is associated with the capacity to avoid immune system detection and to promote therapeutic failures. For this reason, it seems that the investigation for new, alternative methods combating H. pylori should include research of coccoid forms of this pathogen. The current review aimed at collecting information about the activity of antibacterial substances against H. pylori in the context of the morphological variability of this bacterium. The collected data was discussed in terms of the type of substances used, applied research techniques, and interpretation of results. The review was extended by a polemic on the limitations in determining the viability of coccoid H. pylori forms. Finally, recommendations which can help in future research aiming to find new compounds with a potential to eradicate H. pylori have been formulated.

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.

Understanding the dimorphic lifestyles of human gastric pathogen Helicobacter pylori using the SWATH-based proteomics approach

Helicobacter pylori may reside in the human stomach as two morphological forms: the culturable spiral form and the viable but non-culturable (VBNC) coccoid form. This bacterium transforms from spiral to coccoid under in vitro suboptimal conditions. However, both spiral and coccoid have demonstrated its infectivity in laboratory animals, suggesting that coccoid may potentially be involved in the transmission of H. pylori. To determine the relevance of the coccoid form in viability and infectivity, we compared the protein profiles of H. pylori coccoids obtained from prolonged (3-month-old) culture with that of 3-day-old spirals of two H. pylori standard strains using SWATH (Sequential Window Acquisition of all Theoretical mass spectra)-based approach. The protein profiles reveal that the coccoids retained basal level of metabolic proteins and also high level of proteins that participate in DNA replication, cell division and biosynthesis demonstrating that coccoids are viable. Most interestingly, these data also indicate that the H. pylori coccoids possess higher level of proteins that are involved in virulence and carcinogenesis than their spiral counterparts. Taken together, these findings have important implications in the understanding on the pathogenesis of H. pylori-induced gastroduodenal diseases, as well as the probable transmission mode of this bacterium.

Negative Effect of Proton-pump Inhibitors (PPIs) on Helicobacter pylori Growth, Morphology, and Urease Test and Recovery after PPI Removal--An In vitro Study

BACKGROUND

Proton-pump inhibitor (PPI) consumption does lead to false-negative results of Helicobacter pylori diagnostic tests such as biopsy culture and rapid urease test (RUT).

MATERIALS AND METHODS

Helicobacter pylori isolates from 112 dyspeptic patients with (56.5%) or without (43.5%) PPI consumption were recruited for examining the negative effects of omeprazole (OMP), lansoprazole (LPZ), and pantoprazole (PAN) on H. pylori viability, morphology, and urease, in vitro. The effect of a sublethal concentration of OMP on bacterial features and their recovery after removal of OMP was also assessed.

RESULTS

Of 112 culture-positive gastric biopsies, 87.5% were RUT positive and 12.5% RUT negative. There was a significant correlation between negative RUT results and PPI consumption (p < .05). OMP (minimum inhibitory concentration, MIC 32 μg/mL) and LPZ (MIC 8 μg/mL) inhibited the growth of 78.6% of H. pylori isolates. OMP and LPZ inhibited urease of 90.3% of isolates between 0 and 40 minutes and 54.4% between 20 and 40 minutes, respectively. PAN did not inhibit H. pylori growth and urease. Three 3-day (9 days) consecutive subcultures of H. pylori on brucella blood agar (BBA) supplemented with OMP resulted in reduced bacterial viability (1+), compared with control (4+), change of spiral morphology to coccoid, and reduction in pink color intensity in urea agar. Bacterial growth (1+), morphology, and urease test did not improve after the first 3-day and second 3-day (6 days) subcultures on BBA. However, relative recovery occurred after the third 3-day (9 days) subculture and complete recovery was observed after the fourth 3-day (12 days) subculture, as confluent growth (4+), 100% spiral cells, and strong urease test.

CONCLUSION

Proton-pump Inhibitors exert transient negative effects on H. pylori viability, morphology, and urease test. Accordingly, cessation of PPI consumption at least 12 days before endoscopy could help avoiding false-negative results of H. pylori diagnostic tests.

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.

Real-world Helicobacter pylori diagnosis in patients referred for esophagoduodenoscopy: The gap between guidelines and clinical practice

BACKGROUND AND AIMS

Histopathology is the most accurate test to detect H. pylori when performed correctly with unknown validity in daily practice clinic settings. We aimed to determine the rate of potentially false-negative H. pylori results that might be due to continued use of proton pump inhibitors (PPIs) in routine endoscopy practice. We also aimed to establish whether gastroenterologists recommend routine cessation of PPIs before esophagogastroduodenoscopy (EGD) and whether they regularly document that biopsies for H. pylori testing have been taken while the patients are on PPI treatment.

METHODS

Detailed information about three known factors (PPIs, antibiotics and prior H. pylori eradication treatment), which may cause histology or rapid urease test (RUT) to be unreliable, had been prospectively collected through interviews using a questionnaire before each test. Gastric biopsies were stained with H&E for histological analysis.

RESULTS

A total of 409 individuals at three academic gastroenterology institutions were tested 200 times with histology. Fifty-six per cent (68 of 122) of all negative tests fell in the category of continuing PPI use, which had the potential to make the histology and RUT results unreliable.

CONCLUSIONS

These data demonstrate a clear and important gap between current guidelines and real-world practice with regards to the diagnosis of H. pylori during EGD. A negative histology or RUT should be considered false negative until potential protocol violations are excluded. Documentation of PPI use during the EGD should be an integral part of the EGD report. The current practice of taking biopsies for H. pylori testing in patients under PPIs should be reevaluated.

[Role of Helicobacter pylori coccoid forms in infection and recrudescence]

Helicobacter pylori is a spiral Gram-negative bacillus, which colonizes the human stomach and plays a key role in the pathogenesis of a number of gastroduodenal diseases. However, when expose to environmental stressed conditions, such as increased oxygen tension, extended incubation and exposure to antibiotics, Helicobacter pylori is able to entering the viable but nonculturable state, in which the bacterium modifies its morphology from a spiral to coccoid form, as a manifestation of cell adaptation to these adverse conditions. In gastric tissues, viable coccoid forms may remain latent for long time and retain virulence factors, so these forms possibly contribute to the treatment failures and recurrence of Helicobacter pylori infection and gastroduodenal diseases as well. In this review, we will discuss several aspects of cellular adaptation and survival of Helicobacter pylori, antibiotic susceptibility and virulence of coccoid forms and its involvement with recrudescence.

Influence of proton pump inhibitors on gastritis diagnosis and pathologic gastric changes

AIM: To investigate the influence of proton pump inhibitors (PPIs) exposure on the diagnosis of Helicobacter pylori (H. pylori) gastritis and intestinal metaplasia.

METHODS: Chronic PPI use is associated with masking of H. pylori infection. Patients with H. pylori infection are predisposed to gastric and duodenal ulcers, and long-term infection with this organism has been associated with gastric mucosal atrophy and serious long-term complications, such as gastric lymphoma and adenocarcinoma. Three hundred patients diagnosed with gastritis between January 2008 and April 2010 were included in our study. The computerized medical database of these patients was reviewed retrospectively in order to assess whether the type of gastritis diagnosed (H. pylori vs non-H. pylori gastritis) is influenced by PPI exposure. H. pylori density was graded as low, if corresponding to mild density following the Updated Sydney System, or high, if corresponding to moderate or severe densities in the Updated Sydney System.

RESULTS: Patients were equally distributed between males and females with a median age at the time of diagnosis of 50 years old (range: 20-87). The histological types of gastritis were classified as H. pylori gastritis (n = 156, 52%) and non-H. pylori gastritis (n = 144, 48%). All patients with non-H. pylori gastritis had inactive chronic gastritis. Patients with no previous PPI exposure were more likely to be diagnosed with H. pylori gastritis than those with previous PPI exposure (71% vs 34.2%, P < 0.001). Intestinal metaplasia was more likely to be detected in the latter patients (1.4% vs 6.5%, P = 0.023). Multivariate analysis has also demonstrated that in the presence of previous PPI exposure (OR = 0.217, 95%CI: 0.123-0.385), GERD (OR = 0.317, 95%CI: 0.132-0.763, P = 0.01), alcohol intake (OR = 0.396, 95%CI: 0.195-0.804, P = 0.01), the detection of H. pylori was less likely. Chronic use of PPIs may mask H. pylori infections promoting the diagnosis of non-H. pylori gastritis and leads to a significant drop in H. pylori densities and to an increased risk of intestinal metaplasia.

CONCLUSION: The use of PPIs masks H. pylori infection, promotes the diagnosis of non-H. pylori inactive chronic gastritis diagnosis, and increases the incidence of intestinal metaplasia.

Helicobacter pylori and CagA under conditions of iron deficiency

Iron deficiency is the most common nutritional deficiency worldwide and compelling evidence has demonstrated that this condition heightens the risk of gastric cancer. Infection with Helicobacter pylori is the strongest known risk factor for the development of gastric adenocarcinoma. Recent work has demonstrated that, under conditions of iron deficiency, H. pylori-induced gastric carcinogenesis is augmented through increased formation of the strain-specific cag type IV secretion system and enhanced delivery of the bacterial oncoprotein CagA into host cells. Although CagA is a potent virulence factor that promotes oncogenic responses, additional studies have now demonstrated that CagA modulates host cell iron homeostasis in vitro and fundamental metabolic functions of the bacterial cell in vivo. Here we discuss these findings and describe working models by which CagA exerts its effects on gastric epithelial cells, with particular emphasis on its potential role in modulation of host iron homeostasis.

Regulation of Helicobacter pylori Virulence Within the Context of Iron Deficiency

Helicobacter pylori strains that harbor the oncoprotein CagA increase gastric cancer risk, and this risk is augmented under iron-deficient conditions. We demonstrate here that iron depletion induces coccoid morphology in strains lacking cagA. To evaluate the stability of augmented H. pylori virulence phenotypes stimulated by low-iron conditions, H. pylori isolated from iron-depleted conditions in vivo were serially passaged in vitro. Long-term passage decreased the ability of hypervirulent strains to translocate CagA or induce interleukin 8, indicating that hypervirulent phenotypes stimulated by low-level iron conditions are reversible. Therefore, rectifying iron deficiency may attenuate disease among H. pylori-infected persons with no response to antibiotics.

Gastric biopsies: the gap between evidence-based medicine and daily practice in the management of gastric Helicobacter pylori infection

BACKGROUND

Many consider histology to be the gold standard for Helicobacter pylori detection. Because the number and distribution of H pylori organisms vary, particularly in patients taking proton pump inhibitors (PPIs), the American Gastroenterological Association recommends discontinuing PPIs two weeks before endoscopy, and taking biopsies from both the body and antrum.

OBJECTIVE

To assess the influence of clinical practice on the histopathological detection of H pylori infection.

METHODS

Electronic patient records were evaluated for the sites of gastric sampling and PPI use at endoscopy. One hundred fifty cases with biopsies taken from both antrum and body were randomly selected for pathological re-review with special stains. The gastric regions sampled, H pylori distribution and influence of clinical factors on pathological interpretation were assessed.

RESULTS

Between 2005 and 2010, 10,268 biopsies were taken to detect H pylori. Only one region was sampled in 60% of patients (antrum 47%, body 13%). Re-review of biopsies taken from both antrum and body indicated that the correct regions were sampled in only 85 (57%) patients. Of these, 54 were H pylori positive and 96 were H pylori negative. H pylori was present in the antrum in only 15% of the patients and body only in 21%. Of 96 H pylori-negative patients, two were reinterpreted as positive. Forty-seven per cent of patients were taking PPIs at endoscopy, contributing to both false-negative and false-positive diagnoses.

CONCLUSION

Despite national and international guidelines for managing H pylori infection, the American Gastroenterological Association guidelines are infrequently adhered to, with PPIs frequently contributing to false diagnosis; sampling one region only increases the likelihood of missing active infection by at least 15%.

Long-term pretreatment with proton pump inhibitor and Helicobacter pylori eradication rates

AIM

To investigate whether proton pump inhibitor (PPI) pretreatment influences Helicobacter pylori eradication rate.

METHODS

We retrospectively reviewed H. pylori-infected patients who were treated with a standard triple regimen (PPI, amoxicillin 1 g, and clarithromycin 500 mg, all twice daily for 7 d). The diagnosis of H. pylori infection and its eradication was assessed with the rapid urease test, histological examination by silver staining, or the ¹³C-urea breath test. We divided the patients into two groups: one received the standard eradication regimen without PPI pretreatment (Group A), and the other received PPI pretreatment (Group B). The patients in Group B were reclassified into three groups based on the duration of PPI pretreatment: Group B-I (3-14 d), Group B-II (15-55 d), and Group B-III (≥ 56 d).

RESULTS

A total of 1090 patients were analyzed and the overall eradication rate was 80.9%. The cure rate in Group B (81.2%, 420/517) was not significantly different from that in Group A (79.2%, 454/573). The eradication rates in Group B-I, B-II and B-III were 80.1% (117/146), 81.8% (224/274) and 81.4% (79/97), respectively.

CONCLUSION

PPI pretreatment did not affect H. pylori eradication rate, regardless of the medication period.

Assessment of cagE and babA mRNA expression during morphological conversion of Helicobacter pylori from spiral to coccoid

Helicobacter pylori (H. Pylori) is an actively dividing spiral bacterium that changes to coccoid morphology under stressful environments. The infectivity of the coccoids is still controversial. The aim of this study was to determine the viability and expression of two important virulence genes (babA and cagE), in antibiotic-induced coccoid forms. Three strains of H. pylori, the standard 26695 and two clinical isolates (p1, p2) were converted to coccoid form by amoxicillin. Coccoids were identified according to Gram-staining and microscopic morphology. The viability of the cells was analyzed by flow cytometry. The expression of cagE and babA in coccoid forms were evaluated and compared to the spirals by quantitative PCR assay. The coccoid forms were developed after 72 h exposure of H. pylori to ½ MIC of amoxicillin, and the conversion form was completed (100 %) at 144 h in all of three isolates. Flow cytometry analyses showed that the majority of the induced coccoids (90-99.9 %) were viable. Expression of cagE and babA was seen in coccoids; however, in lower rate (cagE, ~3-fold and babA, ~10-fold) than these in spiral forms. Coccoid forms of two clinical isolates significantly expressed higher rate of cagE and babA than standard 26695 strain (P = 0.01). These results suggest that the induced coccoid form of H. pylori is not a passive entity but can actively infect the human by expression of the virulence genes for long time in stomach and probably play a role in chronic and severe disease.

Influence of pretreatment with H2 receptor antagonists on the cure rates of Helicobacter pylori eradication

Background

Pretreatment with a proton pump inhibitor (PPI) reportedly decreases the efficacy of Helicobacter pylori (H. pylori) eradication, however, the effect of pretreatment with an H2 receptor antagonist (H2RA) on H. pylori eradication has not yet been studied. We compared the efficacy of eradication regimen (lansoprazole/amoxicillin/clarithromycin) in patients with H. pylori infection with or without H2RA pretreatment.

Material/Methods

In this retrospective study conducted at three centers, 310 patients with H. pylori infection were treated. The diagnosis of H. pylori infection was made using the rapid urease test, bacterial cultures and histological examination of endoscopic biopsy specimens. The patients were assigned to receive an eradication regimen first or following pretreatment with H2RA. Eradication was assessed using the ¹³C-urea breath test more than 4 weeks after the completion of therapy.

Results

Overall, H. pylori was eradicated in 79.7% of the cases: the eradication rate was 81.6% in the pretreatment group, and 77.6% in the eradication first group (p=0.3799, chi-square test). No significant difference in the eradication rate was observed between the two groups.

Conclusions

Pretreatment with H2RA had no significant influence on the efficacy of H. pylori eradication therapy.

Unusual Helicobacter pylori in gastric resection specimens: an old friend with a new look

Immunohistochemical staining is useful in the diagnosis of Helicobacter pylori-induced gastritis. The authors encountered gastric resection specimens with an unusual pattern of reactivity on H pylori immunostains where the typical morphology of the organism was not recognizable, but the characteristic chronic gastritis associated with infection was present. The authors sought to explore this phenomenon by retrospectively reviewing and immunostaining 28 gastric resection specimens for H pylori. Six cases with large clumps of immunohistochemically positive but morphologically unrecognizable material were identified on light microscopy, corresponding on electron microscopy to clusters of predominantly coccoid H pylori, some located intracellularly. Such organisms were not identifiable without immunohistochemistry, and the phenomenon was not encountered in gastric biopsies. The authors conclude that this staining pattern reflects true H pylori infection that is not diagnosable without immunohistochemistry. Based on its occurrence only in resections, it may be the result of hypoxic or other stress induced when the mucosa is not promptly fixed.

Application of immunohistochemistry to infections

CONTEXT

Pathologists play an important role in the diagnosis or exclusion of infectious diseases. Traditionally, the diagnosis of infectious diseases rely on serologic assays and cultures. Serologic results may be difficult to interpret in the setting of immunosuppression, fresh tissue is not always available for culture, and culture of fastidious pathogens can be difficult and may take weeks or months to yield a result. Although some microorganisms or their cytopathic effects may be readily identifiable on routine and/or histochemical stains, often these changes are not specific or are sparse in the sample evaluated. In these cases, additional immunohistochemical stains are often needed to establish the diagnosis of infection.

OBJECTIVE

To review the current value and limitations of the use of immunohistochemistry in the diagnosis of infectious diseases in formalin-fixed tissue samples.

DATA SOURCES

Literature in Medline and the authors' own experience.

CONCLUSIONS

Immunohistochemistry has proven to be a useful tool in the diagnosis of infectious diseases in tissue samples. Immunohistochemistry is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, are noncultivable, or exhibit an atypical morphology. Finally, it is important to remember that there may be widespread occurrence of common antigens among bacteria and pathogenic fungi and both monoclonal and polyclonal antibodies must be tested for possible cross-reactivity with other organisms.

Increased rate of Helicobacter pylori infection detected by PCR in biopsies with chronic gastritis

Histology is considered a sensitive method for detection of Helicobacter pylori, in gastric biopsies. We investigated the diagnostic potential of qualitative nested (nPCR) and quantitative PCR (qPCR) for detection of H. pylori using different primers on 126 archived gastric biopsies with inflammation and correlated the inflammatory changes with the presence and density of bacteria. H. pylori was detected in 42.8% biopsies by histology and PCR, an additional 15 samples were positive exclusively by PCR: nPCR was positive in all histologically positive samples, but qPCR failed to detect H. pylori in 10 biopsies. The inflammatory score was significantly higher in biopsies positive for H. pylori only by PCR showed a significant higher inflammatory score compared with negative biopsies (mean of neutrophils score, 1.60 vs. 0.90, P < 0.01; mean of mononuclear cells score, 2.27 vs. 1.67, P < 0.01), whereas the inflammatory score was similar compared with biopsies positive for H. pylori by histology (mean of neutrophils score, 1.60 vs. 1.56, not significant; mean of mononuclear cells score, 2.27 vs. 2.20, not significant). A weak correlation between inflammatory score and the density of H. pylori detected by histology was observed. The mean values of H. pylori DNA were significantly higher in histologic-positive than in histologic negative biopsies. We have shown that PCR can detect H. pylori in about 20% of histologic-negative gastric biopsies, indicating the clinical relevance of H. pylori detection by PCR in biopsies with characteristic inflammatory changes.

Meta-analysis: the influence of pre-treatment with a proton pump inhibitor on Helicobacter pylori eradication

BACKGROUND

There is much debate about the influence of pre-treatment with a proton pump inhibitor on Helicobacter pylori eradication. The few studies investigating the influence of pre-treatment on triple and quadruple therapies did not find differences in eradication rates. However, the high eradication rates make it difficult to study factors associated with therapy failure in small populations. In order to overcome this problem we performed a meta-analysis.

METHODS

The literature was searched in order to identify randomized clinical trials comparing modern triple/quadruple therapies for H. pylori eradication without pre-treatment with a proton pump inhibitor with exactly the same regimen with pre-treatment. The overall risk difference (with - without pre-treatment) was calculated by pooling the risk differences of the individual studies weighted by the inverse of their variances.

RESULTS

Nine studies, investigating a total of 773 patients, were identified. There was considerable variation regarding therapy regimen and duration. Pooled eradication rates were 81.3% (312 of 384) for patients with pre-treatment and 81.2% (316 of 389) for patients without pre-treatment. The (weighted) overall risk difference was 0.1% (95% CI: -5%; 5%).

CONCLUSION

Pre-treatment with a proton pump inhibitor does not influence H. pylori eradication.