The role of Helicobacter suis, Fusobacterium gastrosuis, and the pars oesophageal microbiota in gastric ulceration in slaughter pigs receiving meal or pelleted feed.

This study investigated the role of causative infectious agents in ulceration of the non-glandular part of the porcine stomach (pars oesophagea). In total, 150 stomachs from slaughter pigs were included, 75 from pigs that received a meal feed, 75 from pigs that received an equivalent pelleted feed with a smaller particle size. The pars oesophagea was macroscopically examined after slaughter. (q)PCR assays for H. suis, F. gastrosuis and H. pylori-like organisms were performed, as well as 16S rRNA sequencing for pars oesophagea microbiome analyses. All 150 pig stomachs showed lesions. F. gastrosuis was detected in 115 cases (77%) and H. suis in 117 cases (78%), with 92 cases (61%) of co-infection; H. pylori-like organisms were detected in one case. Higher infectious loads of H. suis increased the odds of severe gastric lesions (OR = 1.14, p = 0.038), while the presence of H. suis infection in the pyloric gland zone increased the probability of pars oesophageal erosions [16.4% (95% CI 0.6-32.2%)]. The causal effect of H. suis was mediated by decreased pars oesophageal microbiome diversity [-1.9% (95% CI - 5.0-1.2%)], increased abundances of Veillonella and Campylobacter spp., and decreased abundances of Lactobacillus, Escherichia-Shigella, and Enterobacteriaceae spp. Higher infectious loads of F. gastrosuis in the pars oesophagea decreased the odds of severe gastric lesions (OR = 0.8, p = 0.0014). Feed pelleting had no significant impact on the prevalence of severe gastric lesions (OR = 1.72, p = 0.28). H. suis infections are a risk factor for ulceration of the porcine pars oesophagea, probably mediated through alterations in pars oesophageal microbiome diversity and composition.

Four cases of non-Helicobacter pylori Helicobacter-infected gastritis with duodenal spiral bacilli.

BACKGROUND: Non-Helicobacter pylori Helicobacter (NHPH) is rarely detected in duodenal mucosa due to its preference for slightly acidic environments. Here, we report four cases of NHPH-infected gastritis with duodenal spiral bacilli, potentially NHPH, indicating the possibility of duodenal mucosal infection. CASE PRESENTATION: In every case, gastric mucosa showed endoscopic findings characteristic of NHPH-infected gastritis, and a mucosal biopsy was taken from the duodenal bulb; spiral bacilli were identified under microscopy using Giemsa staining. Case 1, a 46-year-old man, had diffuse spotty redness, mucosal edema, and multiple tiny erosions in the duodenal bulb, along with larger erosions in the second portion of the duodenum upon endoscopic examination. Histopathologically, moderate infiltration of mononuclear cells and neutrophils in the lamina propria and gastric epithelial metaplasia were observed. Case 2, a 54-year-old man, showed an elevated lesion, 1 cm in diameter, with multiple red spots and a few tiny erosions in the duodenal bulb. Histopathologically, mild inflammatory cell infiltration and gastric epithelial metaplasia were observed. In Case 3, a 52-year-old man, endoscopy revealed a flat elevated lesion, 7 mm in diameter, with multiple red spots and a few tiny erosions in the anterior wall of the duodenal bulb. Histopathologically, we observed moderate inflammatory cell infiltration in the gastric antrum and gastric epithelial metaplasia in the duodenal bulb. Case 4, a 40-year-old man, showed mild spotty redness in the duodenal bulb. Histopathologically, mild mononucleocyte infiltration and gastric epithelial metaplasia were observed. A single spiral bacillus was observed in Case 4 by microscopy. In all but Case 2, Helicobacter suis was identified in the gastric juice by polymerase chain reaction analysis. CONCLUSIONS: Spiral bacilli resembling NHPH may infect the duodenal mucosa, particularly the bulb, causing inflammation. Gastric contents entering the duodenum may reduce the intraduodenal pH, promoting NHPH survival and proliferation.

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.

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).

Isolation and characterization of Helicobacter suis from human stomach.

Helicobacter suis, a bacterial species naturally hosted by pigs, can colonize the human stomach in the context of gastric diseases such as gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Because H. suis has been successfully isolated from pigs, but not from humans, evidence linking human H. suis infection to gastric diseases has remained incomplete. In this study, we successfully in vitro cultured H. suis directly from human stomachs. Unlike Helicobacter pylori, the viability of H. suis decreases significantly on neutral pH; therefore, we achieved this using a low-pH medium for transport of gastric biopsies. Ultimately, we isolated H. suis from three patients with gastric diseases, including gastric MALT lymphoma. Successful eradication of H. suis yielded significant improvements in endoscopic and histopathological findings. Oral infection of mice with H. suis clinical isolates elicited gastric and systemic inflammatory responses; in addition, progression of gastric mucosal metaplasia was observed 4 mo postinfection. Because H. suis could be isolated from the stomachs of infected mice, our findings satisfied Koch's postulates. Although further prospective clinical studies are needed, H. suis, like H. pylori, is likely a gastric pathogen in humans. Furthermore, comparative genomic analysis of H. suis using complete genomes of clinical isolates revealed that the genome of each H. suis isolate contained highly plastic genomic regions encoding putative strain-specific virulence factors, including type IV secretion system-associated genes, and that H. suis isolates from humans and pigs were genetically very similar, suggesting possible pig-to-human transmission.

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.

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.

PCR analysis and specific immunohistochemistry revealing a high prevalence of non-Helicobacter pylori Helicobacters in Helicobacter pylori-negative gastric disease patients in Japan: High susceptibility to an Hp eradication regimen.

BACKGROUND: The clinical significance of non-Helicobacter pylori Helicobacter (NHPH) is still unknown. There are many reports of NHPH-infected patients suffering from gastric diseases. Here, we investigated the polymerase chain reaction (PCR) positivity of NHPH infection in gastric disease patients who were negative for H. pylori (Hp) by the rapid urease test and by pathological observation. MATERIALS AND METHODS: We collected the 296 endoscopically obtained gastric mucosal samples of Hp-negative gastric disease patients diagnosed based on a rapid urease test and pathology from 17 hospitals in Japan from September 2013 to June 2019, and we analyzed the existence of Hp and NHPH by PCR. The samples were also treated by indirect immunohistochemistry using an anti-Helicobacter suis VacA paralog antibody and were observed by confocal laser microscopy. RESULTS: Among the 236 non-Hp-eradicated cases, 49 cases (20.8%) were positive for NHPH. Among them, 20 cases were positive for Helicobacter suis, 7 cases were positive for Helicobacter heilmannii sensu stricto/ Helicobacter ailurogastricus (Hhss/Ha), and the other 22 cases could not be identified. The regional differences in the infection rates were significant. Forty percent of the nodular gastritis cases, 24% of the MALT lymphoma, 17% of the chronic gastritis cases, and 33% of the gastroduodenal ulcer cases were NHPH positive. Forty-five patients had been treated with one of the four types of combinations of a proton pump inhibitor and two antibiotics, and in all of these cases, the NHPH diagnosed by PCR was successfully eradicated. Immunohistochemistry using the Helicobacter suis-specific HsvA antibody coincided well with the PCR results. Among the 29 post-Hp eradication cases, three were NHPH positive, including one Hhss/Ha-positive case. Thus, approx. 20% of the Hp-negative non-Hp-eradicated gastric disease patients treated at 17 hospitals in Japan were infected with NHPH.

Comparative virulence of in vitro-cultured primate- and pig-associated Helicobacter suis strains in a BALB/c mouse and a Mongolian gerbil model.

BACKGROUND: Helicobacter suis (H. suis) is the most prevalent gastric non-H. pylori Helicobacter species in humans. This bacterium mainly colonizes the stomach of pigs, but it has also been detected in the stomach of nonhuman primates. The aim of this study was to obtain better insights into potential differences between pig- and primate-associated H. suis strains in virulence and pathogenesis. MATERIALS AND METHODS: In vitro-isolated H. suis strains obtained from pigs, cynomolgus monkeys (Macaca fascicularis), and rhesus monkeys (Macaca mulatta) were used for intragastric inoculation of BALB/c mice and Mongolian gerbils. Nine weeks and six months later, samples of the stomach of inoculated and control animals were taken for PCR analysis and histopathological examination. RESULTS: The cynomolgus monkey-associated H. suis strain only colonized the stomach of mice, but not of Mongolian gerbils. All other H. suis strains colonized the stomach in both rodent models. In all colonized animals, severe gastric inflammation was induced. Gastric lymphoid follicles and destruction of the antral epithelium were observed in infected gerbils, but not in mice. Infection with both pig- and primate-associated H. suis strains evoked a similar marked Th17 response in mice and gerbils, accompanied by increased CXCL-13 expression levels. CONCLUSIONS: Apart from the cynomolgus monkey-associated strain which was unable of colonizing the stomach of Mongolian gerbils, no substantial differences in virulence were found in rodent models between in vitro-cultured pig-associated, cynomolgus monkey-associated and rhesus monkey-associated H. suis strains. The experimental host determines the outcome of the immune response against H. suis infection, rather than the original host.

Species-specific immunity to Helicobacter suis.

BACKGROUND: Helicobacter (H.) suis is mainly associated with pigs, but is also the most prevalent gastric non-H. pylori Helicobacter species found in humans. Both H. pylori and H. suis may cause persistent infection of the stomach. Several immune evasion mechanisms have been proposed for H. pylori, which focus to a great extent on its major virulence factors, which are absent in H. suis. The aim of this study was to gain more knowledge on immune evasion by H. suis. MATERIALS AND METHODS: Cytokine expression kinetics were monitored in the stomach of BALB/c mice experimentally infected with H. suis. The cytokine expression profile in the stomach of naturally H. suis-infected pigs was also determined. Subsequently, the effect of H. suis on murine and porcine dendritic cell (DC) maturation and their ability to elicit T-cell effector responses was analyzed. RESULTS: Despite a Th17/Th2 response in the murine stomach, the inflammatory cell influx was unable to clear H. suis infection. H. suis-stimulated murine bone marrow-derived dendritic cells induced IL-17 secretion by CD4+ cells in vitro. Natural H. suis infection in pigs evoked increased expression levels of IL-17 mRNA in the antrum and IL-10 mRNA in the fundus. In contrast to mice, H. suis-stimulated porcine monocyte-derived dendritic cells were unable to express MHCII molecules on their cell surface. These semimature DCs induced proliferation of T-cells, which showed an increased expression of TGF-ß and FoxP3 mRNA levels. CONCLUSIONS: Helicobacter suis might evade host immune responses by skewing toward a Treg-biased response.