Helicobacter heilmannii infection: clinical, endoscopic and histopathological features in Japanese patients

Endoscopic features differentiating non-Helicobacter pylori Helicobacter-induced gastric mucosa-associated lymphoid tissue lymphoma with a nodular gastritis-like appearance and H. pylori-induced conventional nodular gastritis

OBJECTIVES

Conventional nodular gastritis has been known to be caused by Helicobacter pylori infection. Several cases of gastric mucosa-associated lymphoid tissue (MALT) lymphoma with non-H. pylori Helicobacters (NHPH) exhibit endoscopic findings resembling nodular gastritis. Considering the differences in malignancy, distinguishing between these two conditions is crucial. This study aimed to identify the distinguishing endoscopic features of NHPH-induced gastric MALT lymphoma with nodular gastritis-like appearance (NHPHi-MNG) and H.-induced conventional nodular gastritis (HPi-NG).

METHODS

Between 2011 and 2022, we analyzed 17 patients with NHPHi-MNG and 50 patients with HPi-NG at Hiroshima University Hospital and evaluated nodule morphology and distribution patterns.

RESULTS

Compared with the HPi-NG group, the NHPHi-MNG group exhibited significantly larger nodules (2.5 vs. 2.0 mm, P < 0.05) with protruded morphology (protruded/superficial, elevated: 14/3 vs. 8/42, P < 0.05), most prominently in the gastric angulus. The variability in nodule size was significantly higher in the NHPHi-MNG group than in the HPi-NG group (0.85 vs. 0.37 mm, P < 0.05), reflecting nodule heterogeneity. The distance from the gastric angulus to the proximal end of the nodular lesions was significantly greater in the NHPHi-MNG group than in the HPi-NG group (4.4 vs. 1.7 cm, P < 0.05). The nodules in the HPi-NG group were smaller, superficial, elevated, and most prominent in the gastric antrum compared with those in the NHPHi-MNG group. They were predominantly distributed in the gastric antrum with a homogeneous morphology.

CONCLUSION

NHPHi-MNG and HPi-NG can be endoscopically differentiated according to nodule morphology and distribution. Recognizing these distinguishing features is essential for an accurate diagnosis.

Asia-Pacific Survey on the Management of Helicobacter pylori Infection

BACKGROUND AND AIM

Gastric cancer (GC)-related incidence and mortality rates remain high owing to Helicobacter pylori infection in Asia, and the importance of primary and secondary prevention of GC has been well recognized. We aimed to investigate the extent of overall agreement among clinicians in the Asia-Pacific region regarding the management of H. pylori infection.

METHODS

The Upper Gastrointestinal (GI) Focus Group of the Asian Pacific Association of Gastroenterology-Emerging Leaders Committee developed an international survey, which was distributed to 98 clinicians in the Asia-Pacific region, compromising an online questionnaire focusing on the management of H. pylori infection.

RESULTS

Participants responded from Japan (15, 15.3%), Hong Kong (15, 15.3%), Thailand (33, 33.7%), Vietnam (23, 23.5%), Malaysia (4, 4.1%), Singapore (3, 3.1%), and others (5, 5.1%). The most common first-line eradication regimen was clarithromycin (CAM) triple therapy, including proton pump inhibitor (PPI), amoxicillin (AMPC), and CAM (64.3%) for 14 days (70.4%). The most common second-line eradication regimen was levofloxacin (LVX) triple therapy, including PPI, AMPC, and LVX (22.4%) for 14 days (67.3%). Eradication therapy was deemed necessary for all asymptomatic adults and minors (aged ≤ 17 years) currently infected with H. pylori by 81.6% and 64.3% of respondents, respectively, with 82.7% considering upper GI endoscopy for GC screening useful in the secondary prevention of GC.

CONCLUSION

There appears to be a growing consensus among clinicians, acknowledging the necessity of eradication therapy. We anticipate that this study will establish a new benchmark in preventive medicine aimed at eradicating GC in the Asia-Pacific region.

Helicobacter heilmannii Infection With Concurrent Gastric Cancer: A Case Report

Helicobacter heilmannii (H. heilmannii), a zoonotic pathogen, is increasingly recognized as a cause of gastritis and a potential risk factor for gastric cancer, despite its rarity. Here, we report a case of multiple synchronous early gastric cancers in a female patient in her 40s with H. heilmannii-associated gastritis. She underwent an esophagogastroduodenoscopy (EGD) for the evaluation of gastric discomfort. Endoscopy revealed cobblestone-like gastritis. Histological examination confirmed a signet ring cell carcinoma. Helicobacter pylori (H. pylori) antibody test was negative, and spiral-shaped bacteria were detected by Giemsa staining and real-time polymerase chain reaction (PCR), confirming H. heilmannii infection. Endoscopic submucosal dissection achieved curative resection without recurrence. Helicobacter heilmannii-induced gastritis presents distinct features, including a cobblestone-like appearance and lymphocyte-dominant infiltration, differing from H. pylori-associated gastritis. Chronic inflammation and immune modulation caused by H. heilmannii infection may contribute to carcinogenesis. Considering the diagnostic challenges and zoonotic transmission risks, enhanced awareness of H. heilmannii-associated gastric cancer is essential. This case highlights the importance of identifying H. heilmannii in H. pylori-negative gastritis and its potential role in gastric carcinogenesis. Further research is required to elucidate the pathogenic mechanisms and establish effective management protocols.

Triple-drug combination therapy versus six-month proton pump inhibitor monotherapy in non-Helicobacter pylori Helicobacter eradication, and hyperacid environment preference of Helicobacter suis: a clinical study

BACKGROUND

At present, eradication regimens for non-Helicobacter pylori Helicobacter (NHPH) have not been established yet. We investigated effectiveness of the standard triple-drug combination therapy for Helicobacter pylori eradication and of a proton pump inhibitor (PPI) monotherapy in eradication of NHPH.

METHODS

Subjects were the patients who were diagnosed with NHPH-infected gastritis based on microscopic findings, helical-shaped organisms obviously larger than Helicobacter pylori, in the gastric mucosal specimens using Giemsa staining at Kenwakai Hospital between November 2010 and September 2021, whose NHPH species were identified by polymerase chain reaction (PCR) analysis of urease genes in endoscopically-biopsied samples, and who consented to NHPH eradication with either the triple-drug combination therapy for one week or a PPI monotherapy for six months. Six months after the completion of eradication, its result was determined with esophagogastroduodenoscopy, microscopic examination, and PCR analysis. In cases of unsuccessful eradication, a second eradication with the other therapy was suggested to the patient.

RESULTS

PCR analysis detected NHPH in 38 patients: 36 as Helicobacter suis and two as Helicobacter heilmannii/Helicobacter ailurogastricus. Fourteen Helicobacter suis-infected and one Helicobacter heilmannii/Helicobacter ailurogastricus-infected patients requested eradication therapy. The triple-drug combination therapy succeeded in four of five patients, while the PPI monotherapy succeeded in five of 10 patients. Three of five patients who had been unsuccessful with the latter therapy requested the triple-drug combination therapy as the second eradication and all three were successful. In total, the triple-drug combination therapy succeeded in seven out of eight (87.5%) attempted cases, while the PPI monotherapy in five out of 10 (50%) attempted cases.

CONCLUSIONS

In NHPH eradication, the triple-drug combination therapy was considered to be effective to some extent and to become the first-line therapy. While, although less successful, PPI monotherapy appeared to be a potentially promising option particularly for patients with allergy or resistance to antibiotics. Effectiveness of PPI monotherapy may be attributed to hyperacid environment preference of Helicobacter suis and PPI's acid-suppressive effect. Additionally, male predominance in NHPH-infected gastritis patients may be explained by gender difference in gastric acid secretory capacity. However, further evidence needs to be accumulated.

STUDY REGISTRATION

This study was approved by the Research Ethics Committee of Kenwakai Hospital (No. 2,017,024).

Diagnosis by combination of endoscopic findings helps differentiate non-Helicobacter pylori Helicobacter-infected gastritis from Helicobacter pylori-infected gastritis

BACKGROUND

The characteristic endoscopic findings of non-Helicobacter pylori Helicobacter (NHPH) gastritis, including white marbled appearance and crack-like mucosa, have been reported. However, these findings can also manifest in H. pylori (HP)-infected gastritis. This study compared NHPH gastritis and mild atrophic HP gastritis to identify features that may enhance NHPH diagnosis.

MATERIALS AND METHODS

A total of 2087 patients underwent upper gastrointestinal endoscopy and were histologically evaluated by multiple gastric mucosal biopsies according to the updated Sydney System (USS) at Shinshu University Hospital between 2005 and 2023. Among them, nine patients were classified into the NHPH group and 134 patients with HP infection and mild atrophy were classified into the HP group for retrospective comparisons of endoscopic findings and clinicopathological characteristics.

RESULTS

All nine patients in the NHPH group (eight males [89%], median ± standard deviation [SD] age: 49 ± 13.0 years) were infected with H. suis. The 134 patients in the HP group contained 70 men (52%) and had a median ± SD age of 35 ± 19.9 years. Endoscopic findings were statistically comparable for white marbled appearance (three patients [33%] in the NHPH group and 37 patients [31%] in the HP group) and crack-like mucosa (three patients [33%] and 27 patients [20%], respectively). Diffuse redness was significantly less frequent in the NHPH group (one patient [14%] vs. 97 patients [72%], p < 0.001). White marbled appearance or crack-like mucosa without diffuse redness was significantly more common in the NHPH group (56% vs. 13%, p = 0.004), with a sensitivity and specificity of 56% and 87%, respectively. Mean USS neutrophil infiltration and Helicobacter density scores were significantly higher in the HP group (both p < 0.01), which might have influenced the endoscopic findings of diffuse redness.

CONCLUSIONS

When endoscopic findings of white marbled appearance or cracked-like mucosa are present, evaluation for diffuse redness may contribute to a more accurate diagnosis of NHPH gastritis.

No significant association between non-Helicobacter pylori Helicobacter infection with gastritis-related indices and gastric cancer

BACKGROUND

Non-Helicobacter pylori Helicobacter (NHPH) has recently been linked to various gastric diseases. However, the relationship between NHPH infection and gastric cancer remains controversial. This study aimed to identify the effect of NHPH infection on gastritis and gastric cancer development.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded tissues were obtained from 73 patients with gastric cancer, of whom 21 cases were Helicobacter pylori (Hp) current infection, 37 cases were Hp previous infection, and 15 cases were Hp naïve infection, and were screened for NPHPs using polymerase chain reaction. The results were compared with NHPH infection rates in the patients with gastritis-related diseases reported in the previous study. We evaluated the association of NHPH infection with gastritis and clinicopathological features of gastric cancer.

RESULTS

NHPH infection rates were 4/21 (19%) in "Hp current" patients, 4/37 (11%) in "Hp previous" infection patients, and 1/15 (7%) in "Hp naïve" patients, showing no significant difference in infection rates based on Hp infection status. NHPH infection rates in gastric cancer patients were similar to those in the patients with gastritis-related diseases reported in the previous study. A comparison of NHPH-positive and negative patients showed no significant differences in atrophic gastritis status, serum gastritis markers, or clinicopathological characteristics of gastric cancer, such as localization, size, gross type, differentiation, or depth.

CONCLUSIONS

The association between gastric cancer and NHPH infection would have important implications for gastric cancer prevention, diagnostics, and treatment, however, no significant association was found in this particular population.

Bacterial infection-driven lymphomagenesis

PURPOSE OF REVIEW

The first convincing evidence for a causal relationship between bacterial infection and lymphomagenesis came from the link between gastric lymphoma and chronic Helicobacter pylori gastritis. This review will summarize the current epidemiological, clinical, and biological evidence of a causative role of bacteria in the development of malignant lymphomas, particularly, the extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type.

RECENT FINDINGS

Other microorganisms have been associated with specific extranodal lymphoma sites with variable and not always definitive, evidence, including Chlamydia psittaci , Borrelia burgdorferi , Campylobacter jejuni and, most recently, Coxiella Burnetii . According to most plausible models, lymphoma growth is a consequence of continuous antigenic stimulation induced by chronic infection. However, some evidence of a direct oncogenic role of H. pylori has been provided, too.

SUMMARY

Lymphomas are not the result of a single cause but multifactorial diseases, influenced by a variety of genetic and environmental elements. Hence, ascertaining the specific contribution of bacterial infections is not always easy. Nevertheless, the eradication of the associated chronic infection may result in sustained lymphoma regression. Moreover, the association between infections and lymphoma may offer opportunities for reducing lymphoma incidence by preventing the predisposing infections or treating them early.

Gastric Helicobacter species associated with dogs, cats and pigs: significance for public and animal health

This article focuses on the pathogenic significance of Helicobacter species naturally colonizing the stomach of dogs, cats and pigs. These gastric "non-Helicobacter (H.) pylori Helicobacter species" (NHPH) are less well-known than the human adapted H. pylori. Helicobacter suis has been associated with gastritis and decreased daily weight gain in pigs. Several studies also attribute a role to this pathogen in the development of hyperkeratosis and ulceration of the non-glandular stratified squamous epithelium of the pars oesophagea of the porcine stomach. The stomach of dogs and cats can be colonized by several Helicobacter species but their pathogenic significance for these animals is probably low. Helicobacter suis as well as several canine and feline gastric Helicobacter species may also infect humans, resulting in gastritis, peptic and duodenal ulcers, and low-grade mucosa-associated lymphoid tissue lymphoma. These agents may be transmitted to humans most likely through direct or indirect contact with dogs, cats and pigs. Additional possible transmission routes include consumption of water and, for H. suis, also consumption of contaminated pork. It has been described that standard H. pylori eradication therapy is usually also effective to eradicate the NHPH in human patients, although acquired antimicrobial resistance may occasionally occur and porcine H. suis strains are intrinsically less susceptible to aminopenicillins than non-human primate H. suis strains and other gastric Helicobacter species. Virulence factors of H. suis and the canine and feline gastric Helicobacter species include urease activity, motility, chemotaxis, adhesins and gamma-glutamyl transpeptidase. These NHPH, however, lack orthologs of cytotoxin-associated gene pathogenicity island and vacuolating cytotoxin A, which are major virulence factors in H. pylori. It can be concluded that besides H. pylori, gastric Helicobacter species associated with dogs, cats and pigs are also clinically relevant in humans. Although recent research has provided better insights regarding pathogenic mechanisms and treatment strategies, a lot remains to be investigated, including true prevalence rates, exact modes of transmission and molecular pathways underlying disease development and progression.

Investigation of endoscopic findings in nine cases of Helicobacter suis-infected gastritis complicated by gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND

We have previously reported that eradication therapy was more effective against Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma in non-Helicobacter pylori Helicobacter (NHPH)-positive cases than in NHPH-negative cases and that the infection status of NHPH could be a predictive marker for the efficacy of eradication therapy for H. pylori negative gastric MALT lymphoma. However, a diagnostic test for NHPH infection has not yet been clinically established. In this study, we investigated the endoscopic findings in cases of H. suis-infected gastritis associated with gastric MALT lymphoma reported at our institution.

MATERIALS AND METHODS

Participants were selected from cases of gastric MALT lymphoma who underwent esophagogastroduodenoscopy at Hiroshima University Hospital, who were negative for the API2-MALT1 gene, and who received eradication therapy as a first-line treatment. We examined the endoscopic findings in nine cases from this group in which H. suis infection was confirmed by polymerase chain reaction.

RESULTS

Endoscopic findings, such as cracked mucosa, spotty redness, nodular gastritis-like appearance, and white marbled appearance, which have been reported as characteristics of NHPH gastritis, were observed in multiple cases. The most common endoscopic findings in this study were cracked mucosa (7/9 cases), followed by spotty redness (6/9 cases), nodular gastritis-like appearance (5/9 cases), and white marbled appearance (2/9 cases).

CONCLUSIONS

Our study may serve as a reference for re-evaluation of the diagnostic criteria for H. suis infection and indications for eradication therapy, particularly for cases of H. pylori negative gastric MALT lymphoma, where endoscopic findings such as those seen in this study were observed in the background mucosa.

Clinical aspects of Helicobacter heilmannii-associated gastritis in patients with dyspepsia: A systematic review and meta-analysis

BACKGROUND

The clinical relevance of Helicobacter heilmannii (H. heilmannii) infection in patients with upper gastrointestinal diseases is not yet fully understood. The main purpose of this study was to evaluate the clinical, endoscopic, histopathological, and therapeutic features of H. heilmannii.

METHODS

To retrieve the relevant studies, we conducted a comprehensive systematic search of global databases such as the ISI Web of Science, PubMed, Scopus, Embase, and Google Scholar. After confirming the studies based on the inclusion criteria statistical analysis was performed using Comprehensive Meta-Analysis software.

RESULTS

In our study, the prevalence of infection with H. heilmannii was measured at 1.9% (95% CI: 0.8-4.2). The prevalence of H. heilmannii in Asian population was higher than Western countries (3.1% vs. 1.2%, respectively). Interestingly, the frequency of coinfection with both H. pylori and H. heilmannii was 15.4% (95% CI: 5.2-37.6). The most common endoscopic findings were chronic gastritis, hyperplasia, and erosion. In addition, our results showed that in people infected with this bacterium, gastric inflammation is typically chronic, focal, and less active than Helicobacter pylori (H. pylori) gastritis. Conventional treatment of H. pylori can lead to the eradication of H. heilmannii.

CONCLUSION

In general, H. heilmannii infection is significantly associated with mild chronic gastritis and can be treated with standard anti-H. pylori treatment.

Application of electron microscopy in gastroenterology

Electron microscopy has long been used in research in the fields of life sciences and materials sciences. Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX) analyses have also been performed in the field of gastroenterology. Electron microscopy and EDX enable (1) Observation of ultrastructural differences in esophageal epithelial cells in patients with gastroesophageal reflux and eosinophilic esophagitis; (2) Detection of lanthanum deposition in the stomach and duodenum; (3) Ultrastructural and elemental analyses of enteroliths and bezoars; (4) Detection and characterization of microorganisms in the gastrointestinal tract; (5) Diagnosis of gastrointestinal tumors with neuroendocrine differentiation; and (6) Analysis of gold nanoparticles potentially used in endoscopic photodynamic therapy. This review aims to foster a better understanding of electron microscopy applications by reviewing relevant clinical studies, basic research findings, and the state of current research carried out in gastroenterology science.

Non-Helicobacter pylori Helicobacter (NHPH) positive gastric cancer

Genetic analysis and culturing techniques for gastric non-Helicobacter pylori Helicobacter (NHPH) are progressing. NHPH is reported to accompany nodular gastritis, gastric MALT lymphoma, and mild gastritis. However, only a few gastric cancer cases infected by NHPH have been reported. PCR analysis specific for NHPH and H. pylori was performed for DNA from gastric mucosa of 282 Korean gastric cancer patients, who were treated with endoscopic submucosal dissection. For more precise strain detection of NHPH, NHPH-positive mucosa was stained by immunohistochemistry specific for Helicobacter suis. The Cancer Genome Atlas (TCGA) classification was analyzed for these 3 gastric cancer sub-groups by in situ hybridization and immunohistochemistry. Among 281 patients, 3 patients (1.1%) were positive for NHPH. One patient (Patient 1) was also positive for H. pylori by PCR, another patient (Patient 3) was positive for serum IgG for H. pylori, and the other patient (Patient 2) had no evidence for H. pylori infection. Gastric mucosa of Patients 2 and 3 were positive for H. suis staining. All three NHPH-positive gastric cancers were located in the antrum, and belonged to the Chromosomal Instability Type of TCGA classification. Gastric NHPH can be a cause of gastric cancer, although likely with lower pathogenesis than H. pylori.

Current Status of the Spectrum and Therapeutics of Helicobacter pylori-Negative Mucosa-Associated Lymphoid Tissue Lymphoma

Helicobacter pylori (HP)-unrelated mucosa-associated lymphoid tissue (MALT) lymphoma includes the majority of extragastric MALT lymphomas and a small proportion of gastric MALT lymphomas. Although the role of first-line antibiotics in treating HP-negative gastric MALT lymphomas remains controversial, HP eradication therapy (HPE)-like regimens may result in approximately 20-30% complete remission (CR) for patients with localized HP-negative gastric MALT lymphoma. In these patients, H. heilmannii, H. bizzozeronii, and H. suis were detected in sporadic gastric biopsy specimens. Extragastric MALT lymphoma is conventionally treated with radiotherapy for localized disease and systemic chemotherapy for advanced and metastatic diseases. However, a proportion of extragastric MALT lymphomas, such as ocular adnexal lesions and small intestinal lesions, were reported to be controlled by antibiotics for Chlamydophila psittaci and Campylobacter jejuni, respectively. Some extragastric MALT lymphomas may even respond to first-line HPE. These findings suggest that some antibiotic-responsive tumors may exist in the family of HP-negative MALT lymphomas. Two mechanisms underlying the antibiotic responsiveness of HP-negative MALT lymphoma have been proposed. First, an HPE-like regimen may eradicate the antigens of unknown bacteria. Second, clarithromycin (the main component of HPE) may have direct or indirect antineoplastic effects, thus contributing to the CR of these tumors. For antibiotic-unresponsive HP-negative MALT lymphoma, high-dose macrolides and immunomodulatory drugs, such as thalidomide and lenalidomide, have reported sporadic success. Further investigation of new treatment regimens is warranted.

Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma in the Gastrointestinal Tract in the Modern Era

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) typically arises from sites such as the stomach, where there is no organized lymphoid tissue. Close associations between Helicobacter pylori and gastric MALT lymphoma or Campylobacter jejuni and immunoproliferative small intestinal disease (IPSID) have been established. A subset of tumors is associated with chromosomal rearrangement and/or genetic alterations. This disease often presents as localized disease, requiring diverse treatment approaches, from antibiotic therapy to radiotherapy and immunochemotherapy. Eradication therapy for H. pylori effectively cures gastric MALT lymphoma in most patients. However, treatment strategies for H. pylori-negative gastric MALT lymphoma are still challenging. In addition, the effectiveness of antibiotic therapy has been controversial in intestinal MALT lymphoma, except for IPSID. Endoscopic treatment has been noted to usually achieve complete remission in endoscopically resectable colorectal MALT lymphoma with localized disease. MALT lymphoma has been excluded from post-transplant lymphoproliferative disorders with the exception of Epstein-Barr virus (EBV)-positive marginal zone lymphoma (MZL). We also describe the expanding spectrum of EBV-negative MZL and a close association of the disease with the gastrointestinal tract.

Prevalence, clinical features, and esophagogastroduodenoscopy (EGD) findings of non-Helicobacter pylori Helicobacter infection: A study of 50 cases at a single facility in Japan

BACKGROUND AND AIM

There are only a few reports of non-Helicobacter pylori Helicobacter (NHPH) gastritis in Japanese patients. We aimed to examine its prevalence, clinical features, and esophagogastroduodenoscopy (EGD) findings based on 50 patients encountered in one facility.

MATERIALS AND METHODS

Subjects were all patients who had undergone gastric mucosal biopsy endoscopically at Kenwakai Hospital for approximately 10 years. NHPH infection was diagnosed by microscopic findings of Giemsa staining performed on all specimens. PCR analysis of urease genes was performed to detect and identify NHPH, when informed consent was obtained. Helicobacter pylori-diagnostic tests were also performed. NHPH-infected patients were questioned about symptoms and animal contact.

RESULTS

NHPH gastritis was found in 50 of 3847 patients (1.30%). The percentage increased to 3.35% (30 of 896 patients) in the latter 2 years and 4 months with increasing recognition of its characteristic endoscopic findings by endoscopists. PCR analysis, performed in 30 patients, detected NHPH in 28 patients: 26 as Helicobacter suis and 2 as Helicobacter heilmanii/Helicobacter ailurogastricus. Helicobacter pylori-diagnostic tests were almost negative. However, anti-H. pylori antibody showed high-negative titer (3.0-9.9 U/ml) in 12. Of 50 patients (consisting of 49 men and 1 woman), almost all were asymptomatic, and 25 were keeping pets. Regarding EGD findings, in all 50 patients, "crack-like mucosa" and/or nodular gastritis was noted in gastric antrum, and regular arrangement of collecting venules (RAC) was noted in gastric corpus. None of the patients infected with NHPH were co-infected with H. pylori.

CONCLUSIONS

The prevalence was finally estimated to be approximately 3.35%. Helicobacter suis was the most common NHPH species. "Crack-like mucosa" and/or nodular gastritis in gastric antrum, RAC in gastric corpus, and H. pylori-negativity by H. pylori-diagnostic tests especially containing a high-negative titer of anti-H. pylori antibody may indicate NHPH infection.

Involvement of non-Helicobacter pylori helicobacter infections in Helicobacter pylori-negative gastric MALT lymphoma pathogenesis and efficacy of eradication therapy

BACKGROUND

Eradication therapy is known to be effective against Helicobacter pylori-positive gastric MALT lymphoma but predicting the efficacy of eradication therapy against Helicobacter pylori-negative gastric MALT lymphoma is difficult. Recent reports have shown that non-Helicobacter pylori helicobacter infections induce gastric MALT lymphoma, and we aimed to clarify whether non-Helicobacter pylori helicobacter infections are associated with the efficacy of eradication therapy.

METHODS

We analyzed eradication therapy as a first-line treatment for 182 cases of gastric MALT lymphoma, classified according to Helicobacter pylori infection and API2-MALT1 mutation status. We also evaluated the non-Helicobacter pylori helicobacter infection status in 29 Helicobacter pylori-negative cases via PCR with DNA extracted from paraffin-embedded biopsy tissues. Finally, we analyzed the relationship between non-Helicobacter pylori helicobacter infection status and eradication therapy outcome.

RESULTS

The API2-MALT1 mutation was observed in 13/182 patients (7.1%), none of whom were cured by eradication therapy. Helicobacter pylori-negative cases had a significantly higher non-Helicobacter pylori helicobacter infection rate than Helicobacter pylori-positive cases (16/29, 55% vs. 3/29, 10%; P < 0.05). Among the Helicobacter pylori-negative cases, non-Helicobacter pylori helicobacter-positive cases had a significantly higher complete response rate than non-Helicobacter pylori helicobacter-negative cases (12/16, 75% vs. 3/13, 23%; P < 0.05).

CONCLUSION

Helicobacter pylori-negative and API2-MALT1-negative gastric MALT lymphoma cases exhibited a high rate of non-Helicobacter pylori helicobacter infections, which may have contributed to the success of eradication therapy. Therefore, we recommend eradication therapy as a first-line treatment for non-Helicobacter pylori helicobacter-positive gastric MALT lymphoma.

Acute Peptic Ulcer Disease Caused by Non-Helicobacter pylori-Helicobacter

Human infection by Non-Helicobacter pylori-Helicobacter is rare and most commonly transmitted through direct contact with animals. The clinical presentation in most cases is chronic epigastric abdominal pain and it usually leads to chronic gastritis. We present an uncommon case of a patient with acute onset abdominal pain secondary to acute peptic ulcer disease caused by Helicobacter heilmannii who underwent successful treatment. We also conducted a review of the literature to understand the epidemiology, etiology, clinical presentation, and the best diagnostic and treatment modalities for Non-H. pylori-Helicobacter infections.

Gastric mucosa-associated lymphoid tissue lymphoma in conjunction with multiple lymphomatous polyposis in the context of Helicobacter pylori and Helicobacter suis superinfection

A 53-year-old woman visited a doctor and complained of chest discomfort after meals. Esophagogastroduodenoscopy showed multiple granular elevations in the gastric body. After biopsies from the elevations, she was diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma. Polymerase chain reaction also detected Helicobacter pylori and H. suis. Treatment to eradicate H. pylori and H. suis was successful. Endoscopic examination after the bacterial eradication treatment showed that multiple granular elevations remained in the gastric body; however, no lymphoma cells were found during histopathological examination. Thus, we reported a case of H. pylori-positive gastric MALT lymphoma with a unique morphology associated with H. suis superinfection.

Endoscopic gastric mucosal atrophy as a predictor of colorectal polyps: a large scale case-control study

Although some studies have indicated a correlation between Helicobacter pylori infection and the risk of colorectal neoplasms, these findings have not been consistent and are controversial. This case-control study aimed to investigate the association between endoscopic gastric mucosal atrophy and colorectal polyp occurrence. Records of 7,394 participants who underwent colonoscopy examinations from August 2008 to July 2018 were reviewed retrospectively. A total of 2,404 subjects were registered; 1,565 (65.1%) were in the gastric mucosal atrophy-positive group and 1,138 (47.3%) had colorectal polyps. The multivariate analysis adjusted by age, sex, smoking habits, alcohol habits, hemoglobin A1c, and systolic blood pressure indicated that patients in the gastric mucosal atrophy-positive group more frequently had colorectal polyps compared with patients in the gastric mucosal atrophy-negative group (odds ratio, 3.27; 95% confidence interval, 2.68-4.01; p<0.001). An analysis of the association between gastric mucosal atrophy degree and colorectal polyp status indicated that, compared with mild gastric mucosal atrophy, severe gastric mucosal atrophy was associated with a higher risk of proximal colon polyps (odds ratio, 1.47; 95% confidence interval, 1.05-2.07; p = 0.024) and two or more colorectal polyps (odds ratio, 1.80; 95% confidence interval, 1.30-2.49; p<0.001). In conclusion, gastric mucosal atrophy found during esophagogastroduodenoscopy may be an indication for complete colon screening.

Helicobacter suis infection is associated with nodular gastritis-like appearance of gastric mucosa-associated lymphoid tissue lymphoma

Most patients with gastric mucosa‐associated lymphoid tissue (MALT) lymphoma are infected with Helicobacter pylori, and eradication therapy is the first‐line treatment for localized disease with H pylori infection. However, there were several reports showing effectiveness of eradication therapy in even H pylori negative cases. Gastric MALT lymphomas are endoscopically classified into three common types: superficial, ulcerative, and elevated types. For the past 20 years, we have encountered 200 cases of localized gastric MALT lymphoma. Among them, only 4 cases (2%) showed similar macroscopic findings to those of nodular gastritis (gastric MALT lymphoma with nodular gastritis‐like appearance; M‐NGA). Here, we compared clinicopathological characteristics and prevalence of non‐H pylori Helicobacter (NHPH) infection between M‐NGA and other common types of gastric MALT lymphoma. To examine the prevalence of NHPH infection, DNA was extracted from formalin‐fixed paraffin‐embedded biopsy tissues from four cases of M‐NGA, 20 cases of common endoscopic types of gastric MALT lymphoma, and 10 cases of nodular gastritis. We used a highly sensitive polymerase chain reaction assay to detect the presence of five species of NHPH (Helicobacter suis, H felis, H bizzozeronii, H salomonis, and H heilmannii). H suis infection was detected in 4, 2, and 0 of the 4, 20, and 10 cases of M‐NGA, other types of gastric MALT lymphoma, and nodular gastritis, respectively. Other NHPH species were not detected in any cases. Complete response rate by eradication therapy was 4/4 in M‐NGA cases. Therefore, nodular gastritis‐like MALT lymphoma, which shows a very rare phenotype, is closely associated with NHPH infection, and eradication therapy may be the first‐choice treatment.

Novel Insights of Lymphomagenesis of Helicobacter pylori-Dependent Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common subtype of gastric lymphoma. Most gastric MALT lymphomas are characterized by their association with the Helicobacter pylori (HP) infection and are cured by first-line HP eradication therapy (HPE). Several studies have been conducted to investigate why most gastric MALT lymphomas remain localized, are dependent on HP infection, and show HP-specific intratumoral T-cells (e.g., CD40-mediated signaling, T-helper-2 (Th2)-type cytokines, chemokines, costimulatory molecules, and FOXP3+ regulatory T-cells) and their communication with B-cells. Furthermore, the reason why the antigen stimuli of these intratumoral T-cells with tonic B-cell receptor signaling promote lymphomagenesis of gastric MALT lymphoma has also been investigated. In addition to the aforementioned mechanisms, it has been demonstrated that the translocated HP cytotoxin-associated gene A (CagA) can promote B-cell proliferation through the activation of Src homology-2 domain-containing phosphatase (SHP-2) phosphorylation-dependent signaling, extracellular-signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), B-cell lymphoma (Bcl)-2, and Bcl-xL. Furthermore, the expression of CagA and these CagA-signaling molecules is closely associated with the HP-dependence of gastric MALT lymphomas (completely respond to first-line HPE). In this article, we summarize evidence of the classical theory of HP-reactive T-cells and the new paradigm of direct interaction between HP and B-cells that contributes to the HP-dependent lymphomagenesis of gastric MALT lymphomas. Although the role of first-line HPE in the treatment of HP-negative gastric MALT lymphoma remains uncertain, several case series suggest that a proportion of HP-negative gastric MALT lymphomas remains antibiotic-responsive and is cured by HPE. Considering the complicated interaction between microbiomes and the genome/epigenome, further studies on the precise mechanisms of HP- and other bacteria-directed lymphomagenesis in antibiotic-responsive gastric MALT lymphomas are warranted.

Histochemistry in the diagnosis of non-neoplastic gastrointestinal disorders

The alimentary tract serves as host to a large number of diseases. In the non-neoplastic group of disorders, conventional histochemistry continues to play an important diagnostic role. It is particularly important in recognizing specific infectious diseases, such as Helicobacter gastritis, Whipple disease, intestinal tuberculosis and other forms of mycobacteriosis, malakoplakia, intestinal spirochetosis, fungal enteritides, amebiasis, cryptosporidiosis, isosporiasis, and microsporidiosis. Those conditions and their histochemical properties are discussed in this review, along with the use of histochemistry in the characterization of structural gastrointestinal disorders. The latter include mucosal metaplasias, amyloidosis, glycogenic acanthosis of the esophagus, lymphocytic-collagenous colitis, gastric neuroendocrine hyperplasia, and pill gastritis.

Presence of gastric Helicobacter species in children suffering from gastric disorders in Southern Turkey

BACKGROUND

Infections with gastric Helicobacter spp. are associated with gastritis, peptic ulceration, and malignancies. Helicobacter pylori is the most prevalent Helicobacter species colonizing the human stomach. Other gastric non-H. pylori helicobacters (NHPHs) have been described in 0.2%-6% of human patients with gastric disorders. Nevertheless, due to difficulties in the diagnosis of NHPH infections and lack of routine screening, this is most likely an underestimation of their true prevalence. To the best of our knowledge, no studies have been performed in the presence of Helicobacter spp. in children suffering from gastric disorders in Southern Turkey.

MATERIALS AND METHODS

In total, 110 children with gastric complaints were examined at the Cukurova University Balcali hospital, Turkey. Gastroscopy was performed to evaluate the presence of gastric mucosal lesions. Biopsies of the pyloric gland zone were taken for histopathological analysis, rapid urease testing, and presence of Helicobacter spp. DNA by PCR.

RESULTS

Based on the PCR results, the prevalence of Helicobacter spp. was 32.7% (36/110). H. pylori was found in 30.9% (34/110), H. suis in 1.8% (2/110), and H. heilmannii/H. ailurogastricus in 0.9% (1/110) of the human patients. A mixed infection with H. pylori and H. suis was present in one patient. The presence of mucosal abnormalities, such as nodular inflammation, ulceration, and hyperemia, as well as gastritis, was significantly higher in Helicobacter spp. positive patients.

CONCLUSION

Helicobacter pylori, H. suis, and H. heilmannii/H. ailurogastricus were present in children with gastric complaints. Infection with these pathogens may be involved in the development of gastritis and ulceration.

Diagnosis of Helicobacter pylori Using Invasive and Noninvasive Approaches

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

Cholesterol-α-glucosyltransferase gene is present in most Helicobacter species including gastric non-Helicobacter pylori helicobacters obtained from Japanese patients

BACKGROUND

Non-Helicobacter pylori helicobacters (NHPHs) besides H. pylori infect human stomachs and cause chronic gastritis and mucosa-associated lymphoid tissue lymphoma. Cholesteryl-α-glucosides have been identified as unique glycolipids present in H. pylori and some Helicobacter species. Cholesterol-α-glucosyltransferase (αCgT), a key enzyme for the biosynthesis of cholesteryl-α-glucosides, plays crucial roles in the pathogenicity of H. pylori. Therefore, it is important to examine αCgTs of NHPHs.

MATERIALS AND METHODS

Six gastric NHPHs were isolated from Japanese patients and maintained in mouse stomachs. The αCgT genes were amplified by PCR and inverse PCR. We retrieved the αCgT genes of other Helicobacter species by BLAST searches in GenBank.

RESULTS

αCgT genes were present in most Helicobacter species and in all Japanese isolates examined. However, we could find no candidate gene for αCgT in the whole genome of Helicobacter cinaedi and several enterohepatic species. Phylogenic analysis demonstrated that the αCgT genes of all Japanese isolates show high similarities to that of a zoonotic group of gastric NHPHs including Helicobacter suis, Helicobacter heilmannii, and Helicobacter ailurogastricus. Of 6 Japanese isolates, the αCgT genes of 4 isolates were identical to that of H. suis, and that of another 2 isolates were similar to that of H. heilmannii and H. ailurogastricus.

CONCLUSIONS

All gastric NHPHs examined showed presence of αCgT genes, indicating that αCgT may be beneficial for these helicobacters to infect human and possibly animal stomachs. Our study indicated that NHPHs could be classified into 2 groups, NHPHs with αCgT genes and NHPHs without αCgT genes.

Prevalence of Gastric Non-Helicobacter pylori-Helicobacters in Japanese Patients with Gastric Disease

BACKGROUND

Non-Helicobacter pylori-helicobacters (NHPH) compose a group of gram negative zoonotic bacteria that may induce in humans gastric diseases including gastritis, gastroduodenal ulcer and MALT lymphoma. Their prevalence in the general population has previously been reported to 0.1-6.2%, although such reports still remain less in number.

AIMS

This study aimed at estimating the prevalence of gastric NHPH in Japanese people, and further aimed at linking this to different gastric diseases and co-infection with H. pylori.

METHODS

Endoscopically obtained biopsy samples from 280 Japanese patients with various gastric diseases were collected. Samples were analyzed by immunohistochemistry and by species-specific PCR for detection of gastric helicobacters.

RESULTS

The total prevalence of gastric NHPH among 280 Japanese patients was 6.1%, and the prevalence of H. pylori was 65.7%. There was no significant difference in prevalence of either NHPH or H. pylori when infected with H. pylori or NHPH, respectively. NHPH infection was found to be the highest in patients with gastric MALT lymphoma and duodenal ulcer, the former being independent of co-infection with H. pylori and the latter being dependent.

CONCLUSIONS

This study reports a total prevalence of 6.1% of gastric NHPH in Japanese patients, and further highlights gastric MALT lymphoma and duodenal ulcer (when co-infected with H. pylori) as important related diseases.

Helicobacter Species Identified in Captive Sooty Mangabeys (Cercocebus atys) with Metastatic Gastric Adenocarcinoma

BACKGROUND

Of all human cancers, gastric carcinoma is the one of the leading causes of death. Helicobacter pylori is considered a major etiologic agent of this disease. Spontaneously occurring gastric carcinoma is a rare diagnosis in nonhuman primates. A 2011 case report documented a high incidence of gastric adenocarcinoma in a closed colony of captive sooty mangabeys (Cercebus atys). However, H. pylori infection was not detected in these animals.

MATERIALS AND METHODS

In this study, using archived formalin-fixed, paraffin-embedded stomach sections of these animals alternative methodologies were used to identify H. pylori and other non-H. pylori Helicobacter species. In addition, two additional cases of sooty mangabeys with metastatic gastric carcinoma are characterized.

RESULTS

Using fluorescent in situ hybridization, we identified gastric H. suis in 75% of archived and new gastric carcinoma cases. In the two newly reported cases, H. suis and a novel Helicobacter species were detected via PCR and sequence analysis of the 16S rRNA gene. H. pylori was not identified in any of the gastric carcinoma cases via FISH and/or PCR and sequence analysis of Helicobacter spp. in DNA from of available tissues.

CONCLUSIONS

This report is the first to characterize Helicobacter species infection in spontaneous gastric carcinoma with metastatic potential in nonhuman primates.

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.

Two Cases of Chronic Gastritis with non-Helicobacter pylori Helicobacter Infection

Two men, 48 and 54 years of age, were referred for medical checkups without any particular symptoms. Upper gastrointestinal endoscopy showed a normal gastric body, but white marbled appearance in the lesser curvature of the gastric angle and antrum. Biopsy specimens revealed relatively long and tightly coiled organisms. The two patients were diagnosed as having non-Helicobacter pylori helicobacter (NHPH) infection according to the findings of pathological and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. After triple therapy (amoxicillin, clarithromycin, and rabeprazole), endoscopy showed an improvement of the white marbled lesions and biopsy specimens showed no NHPH. The white marbled appearance limited to the gastric angle and antrum may be a potential characteristic finding of NHPH-infected gastritis.

Helicobacter pylori Infection in Rural and Urban Dyspeptic Patients from Venezuela

The goal of this work was to assess the Helicobacter pylori prevalence in a rural mestizo population and compare it to an urban population from Venezuela. The study was performed in gastric juice samples of 71 dyspeptic patients from Caracas (urban) and 39 from Tucupita (rural), in the Orinoco Delta region. Helicobacter pylori was detected by amplification of 16S rRNA, glmM, and ureA genes in 55.0% patients from urban and 87.2% from rural populations. cagA was found positive in 51% and 62% urban and rural patients, respectively. Non-H. pylori Helicobacter species were not detected in the urban population, but was found in 7.7% of patients in the rural study site. Frequency values of the 16S rRNA, glmM, and ureA genes were higher in the rural population. The odds ratio for each gene was 15.18 for 16S rRNA, 2.34 for glmM, 2.89 for ureA, and 1.53 cagA, showing significant differences except for cagA when gene frequency was compared in both populations. These results demonstrate a higher frequency of H. pylori and gastric non-H. pylori Helicobacter infection in a rural mestizo population with low hygienic standards as compared with city dwellers, representing a potential risk for the development of gastroduodenal diseases.

Interferon-γ-producing B cells induce the formation of gastric lymphoid follicles after Helicobacter suis infection

Helicobacter (H.) suis is capable of infecting various animals including humans, and H. suis infections can lead to gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Recently, we reported that interferon-γ (IFN-γ) was highly expressed in the stomachs of H. suis-infected mice, but the direct relationship between the upregulation of IFN-γ expression and the formation of gastric lymphoid follicles after H. suis infection remains unclear. Here, we demonstrated that the IFN-γ produced by B cells plays an important role in the formation of gastric lymphoid follicles after H. suis infection. In addition, IFN-γ-producing B cells evoked gastric lymphoid follicle formation independent of T-cell help, suggesting that they are crucial for the development of gastric MALT induced by Helicobacter infection.

Helicobacter heilmannii sensu lato: An overview of the infection in humans

Helicobacter heilmannii sensu lato (H. heilmannii s.l.) is a group of gastric non-Helicobacter pylori Helicobacter species that are morphologically indistinguishable from each other. H. heilmannii s.l. infect the stomach of several animals and may have zoonotic potential. Although the prevalence of these infections in humans is low, they are associated with gastric pathology, including mucosa-associated lymphoid tissue lymphoma, making them a significant health issue. Here, the taxonomy, epidemiology, microbiology, diagnosis, and treatment of these infections will be reviewed. The gastric pathology associated with H. heilmannii s.l. infections in humans will also be addressed. Finally, the features of the complete bacterial genomes available and studies on species-specific pathogenesis will be reviewed. The understanding of the mechanisms that underlie gastric disease development mediated by the different bacterial species that constitute H. heilmannii s.l. is essential for developing strategies for prevention and treatment of these infections.

Anti-CXCL13 antibody can inhibit the formation of gastric lymphoid follicles induced by Helicobacter infection

Helicobacter suis infects the stomachs of both animals and humans, and can induce gastric mucosa-associated lymphoid tissue (MALT) lymphomas. It is known that CXC chemokine ligand 13 (CXCL13) is highly expressed in the Helicobacter-infected mice and gastric MALT lymphoma patients, but the pathway that links the activation of CXCL13 and the formation of gastric MALT lymphomas remains unclear. In this study, we examined whether CXCL13 neutralization would interfere with the formation of gastric lymphoid follicles including B cells, CD4+T cells, dendritic cells (DCs), and follicular DCs (FDCs) in germinal centers to determine the role of CXCL13 in the formation of B-cell aggregates after H. suis infection. Moreover, the expression of genes associated with the lymphoid follicle formation was also effectively suppressed by anti-CXCL13 antibody treatment. These results suggest that the upregulation of CXCL13 has an important role in the development of gastric MALT lymphomas and highlight the potential of anti-CXCL13 antibody for protection against Helicobacter-induced gastric diseases.

Development of new PCR primers by comparative genomics for the detection of Helicobacter suis in gastric biopsy specimens

BACKGROUND

Although the infection rate of Helicobacter suis is significantly lower than that of Helicobacter pylori, the H. suis infection is associated with a high rate of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In addition, in vitro cultivation of H. suis remains difficult, and some H. suis-infected patients show negative results on the urea breath test (UBT).

MATERIALS AND METHODS

Female C57BL/6J mice were orally inoculated with mouse gastric mucosal homogenates containing H. suis strains TKY or SNTW101 isolated from a cynomolgus monkey or a patient suffering from nodular gastritis, respectively. The high-purity chromosomal DNA samples of H. suis strains TKY and SNTW101 were prepared from the infected mouse gastric mucosa. The SOLiD sequencing of two H. suis genomes enabled comparative genomics of 20 Helicobacter and 11 Campylobacter strains for the identification of the H. suis-specific nucleotide sequences.

RESULTS

Oral inoculation with mouse gastric mucosal homogenates containing H. suis strains TKY and SNTW101 induced gastric MALT lymphoma and the formation of gastric lymphoid follicles, respectively, in C57BL/6J mice. Two conserved nucleotide sequences among six H. suis strains were identified and were used to design diagnostic PCR primers for the detection of H. suis.

CONCLUSIONS

There was a strong association between the H. suis infection and gastric diseases in the C57BL/6 mouse model. PCR diagnosis using an H. suis-specific primer pair is a valuable method for detecting H. suis in gastric biopsy specimens.

Helicobacter heilmannii sensu stricto-related gastric ulcers: A case report

A spiral bacterium (SH9), morphologically different from Helicobacter pylori (H. pylori), was found in a 62-year-old woman’s gastric mucosa. Gastroscopic examination revealed multiple gastric ulcers near the pyloric ring; mapping gastric biopsy showed mild mononuclear infiltration with large lymphoid follicles in the antrum, without corpus atrophy. Urea breath test and H. pylori culture were negative, but Giemsa staining of biopsies revealed tightly coiled bacteria that immunostained with anti-H. pylori antibody. Sequencing of SH9 16S rRNA and the partial urease A and B subunit genes showed that the former sequence had highest similarity (99%; 1302/1315 bp) to Helicobacter heilmannii (H. heilmannii) sensu stricto (H. heilmannii s.s.) BC1 obtained from a bobcat, while the latter sequence confirmed highest similarity (98.3%; 1467/1493 bp) to H. heilmannii s.s. HU2 obtained from a human. The patient was diagnosed with multiple gastric ulcers associated with H. heilmannii s.s. infection. After triple therapy (amoxicillin, clarithromycin, and lansoprazole) with regimen for eradicating H. pylori, gastroscopy showed ulcer improvement and no H. heilmannii s.s. upon biopsy.

Clinical characteristics of Helicobacter heilmannii- versus Helicobacter pylori-associated gastritis in Chinese patients

AIM: To compare the endoscopic and histopathological characteristics of Helicobacter heilmannii (H. heilmannii)- versusHelicobacter pylori (H. pylori)-associated gastritis in Chinese patients.

METHODS: Gastric biopsy specimens from 53559 consecutive patients treated at Peking University Third Hospital from January 2003 to January 2010 were reviewed retrospectively. All cases of chronic gastritis were evaluated based on the Updated Sydney System. Endoscopic and histopathological characteristics of cases with H. heilmannii infection were compared with those with H. pylori infection.

RESULTS: There were 46 cases with H. heilmannii infection (0.1%) and 18326 cases with H. pylori infection (34.2%). Compared to H. pylori-associated gastritis, H. heilmannii-associated gastritis showed a lower bacterial density (P < 0.001), less severe mononuclear cell infiltration (P < 0.001) and neutrophil activity (P < 0.001), and endoscopic findings of H. heilmannii-associated gastritis were devoid of ulcer (P = 0.021). H. heilmannii density showed a significant correlation with neutrophil activity (P = 0.02), but not with chronic inflammation (P = 0.159). The percentages of patients with mucosal atrophy, intestinal metaplasia and intraepthelial neoplasia in the H. heilmannii-associated gastritis group were 23.9%, 21.7% and 4.3%, respectively, and there was no significant difference in the prevalence and degree of these precancerous lesions between the two groups. A case of signet-ring cell carcinoma concomitant with H. heilmannii infection was detected.

CONCLUSION: H. heilmannii-associated gastritis is uncommon and milder than H. pylori-associated gastritis. The observation that there were no significant differences between two groups in the prevalence and degree of mucosal atrophy, intestinal metaplasia and intraepthelial neoplasia suggests that H. heilmannii may be partly responsible for malignant-associated lesions just as H. pylori does. In addition, one case of signet-ring cell carcinoma concomitant with H. heilmannii infection was noted.

Complete remission of gastric plasmacytoma following eradication of "Candidatus Helicobacter heilmannii"

This is the first case report of gastric plasmacytoma associated with "Candidatus Helicobacter heilmannii" ('H. heilmannii') infection. The patient was a 40-year-old woman with epigastric discomfort. Upper gastrointestinal endoscopy demonstrated a white granular lesion on the wall of the gastric body. Histological studies showed numerous eosinophilic globules expanding the lamina propria mucosae. Immunohistochemically, the cells with these globules stained positive for CD138, CD79a, immunoglobulin (Ig) M, and kappa light chain, but negative for CD20, IgG, IgA, and lambda light chain. A diagnosis of plasmacytoma was made. Although a Helicobacter pylori infection was not detected, the patient received H. pylori eradication treatment. Two months after H. pylori eradication treatment, an upper gastrointestinal endoscopy showed a reduction of the white granular lesion. Eighteen months after eradication treatment, endoscopy, endoscopic ultrasonography and histological studies revealed complete remission of the lesion. No relapse has been documented 30 months after the initial diagnosis of plasmacytoma. Retrospectively, analysis of biopsy specimens removed before eradication treatment demonstrated that this patient had 'H. heilmannii' infection. Therefore, H. pylori eradication therapy should be considered as a potential first-line therapy for early-stage gastric plasmacytoma with or without H. pylori infection.

Neonatal Fc receptor for IgG (FcRn) expressed in the gastric epithelium regulates bacterial infection in mice

Neonatal Fc receptors for immunoglobulin (Ig)G (FcRn) assume a central role in regulating host IgG levels and IgG transport across polarized epithelial barriers. We have attempted to elucidate the contribution of FcRn in controlling Helicobacter infection in the stomach. C57BL/6J wild-type or FcRn(-/-) mice were infected with Helicobacter heilmannii, and gastric lesions, bacterial load and the levels of antigen-specific IgG in serum and gastric juice were analyzed. The elevated levels of anti-H. heimannii IgG in gastric juice were observed exclusively in wild-type mice but not in FcRn(-/-) mice. In contrast, an increase in lymphoid follicles and bacterial loads along with deeper gastric epithelium invasion were noted in FcRn(-/-) mice. C57BL/6J wild-type or FcRn(-/-) mice were also infected with Helicobacter pylori SS1, and the results of the bacterial load in stomachs of these mice and the anti-H. pylori IgG levels in serum and gastric juice were similar to those from H. heilmannii infection. Our data suggest that FcRn can be functionally expressed in the stomach, which is involved in transcytosis of IgG, and prevent colonization by H. heilmannii and the associated pathological consequences of infection.

Role of bacteria in oncogenesis

Although scientific knowledge in viral oncology has exploded in the 20th century, the role of bacteria as mediators of oncogenesis has been less well elucidated. Understanding bacterial carcinogenesis has become increasingly important as a possible means of cancer prevention. This review summarizes clinical, epidemiological, and experimental evidence as well as possible mechanisms of bacterial induction of or protection from malignancy.

Induction of high endothelial venule-like vessels expressing GlcNAc6ST-1-mediated L-selectin ligand carbohydrate and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in a mouse model of "Candidatus Helicobacter heilmannii"-induced gastritis and gastric mucosa-associated lymphoid tissue (MALT) lymphoma

BACKGROUND

"Candidatus Helicobacter heilmannii" induce chronic gastritis, which eventually leads to gastric B-cell type mucosa-associated lymphoid tissue (MALT) lymphoma. This study was performed using an animal model of infection with "Candidatus Helicobacter heilmannii" to elucidate how this chronic inflammation is induced or maintained.

MATERIALS AND METHODS

BALB/c mice were infected with the "Candidatus Helicobacter heilmannii" isolate SH4. The animals were examined at 8, 26, 54, and 83 weeks after the infection. The stomach of the animals was resected and immunostained for peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1), "Candidatus Helicobacter heilmannii," and CD45R/B220. An in vitro binding assay with L- and E-selectin·IgM chimeric proteins was performed. Real-time polymerase chain reaction was used to evaluate transcripts of N-acetylglucosamine-6-O-sulfotransferases (GlcNAc6STs), which direct the expression of the PNAd and MAdCAM-1.

RESULTS

Chronic gastritis developed in the infected animals, and its severity increased with the duration of the infection. B-cell type MALT lymphoma developed in some animals at 54 and 83 weeks after infection. PNAd- and MAdCAM-1-expressing high endothelial venule (HEV)-like vessels were induced in infected animals which developed chronic gastritis and MALT lymphoma. The number of HEV-like vessels increased as chronic inflammation progressed. The induced HEV-like vessels were bound by L- and E-selectin·IgM chimeric protein. mRNA expressions of GlcNAc6ST-1 and MAdCAM-1 increased in the infected animals.

CONCLUSIONS

HEV-like vessels expressing GlcNAc6ST-1-mediated L-selectin ligand carbohydrate and MAdCAM-1 may play a crucial role in the pathogenesis of "Candidatus Helicobacter heilmannii"-induced chronic gastritis and MALT lymphoma.

Helicobacter pylori-negative gastritis: seek, yet ye shall not always find

Since its recognition as the causative agent for most cases of gastritis, the prevalence of Helicobacter pylori-induced gastritis has been declining, in part due to the deliberate and inadvertent use of various medications. As a result, pathologists find themselves facing cases of gastritis in which, based upon history and histology, there are expected but undetectable H. pylori organisms. This review explores the 2 possibilities of false-negative and true-negative gastritides, including when and how to search for H. pylori, explanations for absent organisms in cases of true H. pylori gastritis, and other causes of gastritis that may mimic H. pylori infection. The latter group includes reactive gastropathy with focal activity, focally active gastritis and carditis, autoimmune gastritis, granulomatous gastritis, lymphocytic gastritis, and other infections.

Characterization of multiple Helicobacter bizzozeronii isolates from a Finnish patient with severe dyspeptic symptoms and chronic active gastritis

BACKGROUND

Helicobacter pylori is the primary cause of gastritis and peptic ulceration in humans. In a minority of patients with upper gastrointestinal symptoms, long tightly coiled spiral bacteria, provisionally named "Helicobacter heilmannii," are observed in gastric biopsies. These bacteria are extremely fastidious and only one previous study has succeeded in obtaining an isolate in vitro.

MATERIALS AND METHODS

We used two different selective media to isolate "H. heilmannii" from the gastric mucosa of a Finnish patient presenting with severe dyspeptic symptoms. The isolates were characterized by testing for urease and catalase activity, by using light and electron microscopy, and by sequencing of the partial 16S rRNA and ureAB genes. Single-enzyme amplified fragment length polymorphism (sAFLP) was used to analyze the genetic diversity among the isolates.

RESULTS

We obtained 15 isolates from different gastric biopsies prior and three after unsuccessful treatment of the patient. The isolates were identified as Helicobacter bizzozeronii. Eradication therapy was unsuccessful most probably due to high level of resistance to metronidazole. Persistent colonization by the same H. bizzozeronii clone was confirmed by sAFLP, however, small differences between the profiles suggested long-term colonization of the patient.

CONCLUSIONS

Helicobacter bizzozeronii remains the only "H. heilmannii" species isolated from human gastric mucosa although it has been an infrequent observation among "H. heilmannii"-infected patients in PCR-based screening studies. The relevance of H. bizzozeronii and other potentially zoonotic gastric Helicobacter spp. in human disease remains to be determined.