Spiral shaped bacteria in gastric mucosa

Helicobacter suis-Infected Nodular Gastritis and a Review of Diagnostic Sensitivity for Helicobacter heilmannii-Like Organisms

Helicobacter heilmannii-like organisms (HHLOs) are associated with mucosa-associated lymphoid tissue lymphoma and peptic ulcer. However, the sensitivity of diagnostic tests for HHLOs, such as rapid urease test (RUT), urea breath test (UBT) and blood antibody, is not high. Tightly coiled spiral microorganisms were found in the gastric mucosal biopsy specimen of a 48-year-old asymptomatic woman. Her findings were positive for RUT and UBT, but negative for blood antibody and stool antigen against H. pylori. A 7-day course of esomeprazole, amoxicillin and clarithromycin was administered, resulting in the successful eradication of the HHLOs. Analysis of the 16S rRNA and urease genes suggested a diagnosis of the HHLO H. suis. The sensitivity results of RUT, UBT, culture, blood antibody, immunohistochemistry and stool antigen were 40.0, 14.8, 0, 23.1, 40.0 and 0%, respectively. We report asymptomatic nodular gastritis due to an HHLO. Histological techniques, most likely with smears, are expected to be the most effective method for diagnosing infections by HHLOs, and genetic diagnosis by polymerase chain reaction can be very useful to identify the species of HHLOs.

Helicobacter heilmannii gastritis: a histological and immunohistochemical trait

AIM

Biopsies of the gastric antrum were reviewed over a period of 10 years to determine the prevalence of Helicobacter heilmannii in symptomatic subjects from this geographical area and to relate its presence to distinctive histopathological and immunohistochemical features.

METHODS

Biopsies from 7926 symptomatic patients were reviewed. Ten serial sections were stained with haematoxylin and eosin for conventional histology. Another 10 sections were stained with the Gram method for spiral bacteria. When H heilmannii was suspected, 10 additional serial sections were stained with methylene blue to obtain homogeneous colouring. An equal number of sections from patients affected by isolated H heilmannii or H pylori gastritis were analysed by immunohistochemistry to evaluate lymphoid aggregate/mucosal lymphocyte clonality (CD20 and CD3) and tumour necrosis factor alpha (TNF-alpha) in stromal cells.

RESULTS

The prevalence of H heilmannii was 0.1% (eight of 7926), whereas H pylori was present in 60.7% of patients (4813 of 7926). In two of the eight H heilmannii positive patients both helicobacters were found. In all subjects infected by H heilmannii only, distinctive histology (lymphocyte exudation into gastric foveolae) was seen. Lymphoid aggregates, chronic mucosal inflammation with patchy activity, and the absence of epithelial mucus depletion were regular features of H heilmannii gastritis. Immunohistochemistry did not reveal different lymphocyte clonal patterns between H pylori and H heilmannii gastritis: CD20 positive cells were predominant in the centre of aggregates and mucosal infiltrates, whereas CD3 positive cells were prevalent at the periphery of follicles. Only H pylori gastritis showed a significant increase in TNF-alpha positive stromal cells.

CONCLUSION

These data suggest that an unusual lymphocyte reaction, with the tendency to invade the foveolar lumen, is a distinctive histopathological aspect of H heilmannii chronic gastritis, although further studies in a larger series are necessary to confirm this fact. Nevertheless, lymphocyte clones do not differ qualitatively from those found in H pylori infection. Moreover, compared with H heilmannii, H pylori provokes a more intense release of TNF-alpha, suggesting that different inflammatory responses exist to these two organisms.

Emergence of diverse Helicobacter species in the pathogenesis of gastric and enterohepatic diseases

Since Helicobacter pylori was first cultivated from human gastric biopsy specimens in 1982, it has become apparent that many related species can often be found colonizing the mucosal surfaces of humans and other animals. These other Helicobacter species can be broadly grouped according to whether they colonize the gastric or enterohepatic niche. Gastric Helicobacter species are widely distributed in mammalian hosts and are often nearly universally prevalent. In many cases they cause an inflammatory response resembling that seen with H. pylori in humans. Although usually not pathogenic in their natural host, these organisms serve as models of human disease. Enterohepatic Helicobacter species are an equally diverse group of organisms that have been identified in the intestinal tract and the liver of humans, other mammals, and birds. In many cases they have been linked with inflammation or malignant transformation in immunocompetent hosts and with more severe clinical disease in immunocompromised humans and animals. The purpose of this review is to describe these other Helicobacter species, characterize their role in the pathogenesis of gastrointestinal and enterohepatic disease, and discuss their implications for our understanding of H. pylori infection in humans.

The histopathology of human gastric mucosa inhabited by Helicobacter heilmannii-like (Gastrospirillum hominis) organisms, including the first culturable case

The aim was to determine the prevalence of Helicobacter heilmannii-like organisms in human gastric biopsies and the associated histology compared with that of Helicobacter pylori-bearing gastric biopsies. Furthermore, the feasibility of culturing H. heilmannii was examined. A consecutive series of 727 gastric biopsies from 650 patients were prospectively scrutinized for H. heilmannii. Their distribution pattern was recorded as well as the affiliated morphology of the gastric mucosa. Additional biopsies from some of the patients were examined microbiologically. Four cases (0.6%)(95% confidence intervals: 0.01-1.2%) of the examined material harboured H. heilmannii. The bacterial burden was graded as sparse in three cases, moderate in one case. The distribution pattern was patchy; thus, in no case did all biopsies from one endoscopy comprise H. heilmannii. Adhesion to epithelial cells was infrequent. A mild gastritis, active in three cases, characterized all biopsies. Lymphoid aggregates occurred in biopsies from three patients. Micropapillary tufting of the epithelial layer and intestinal metaplasia were not apparent. Culture studies proved successful in the one of the four cases assayed. In conclusion the morphology of H. heilmannii-bearing mucosa deviates from that of H. pylori-associated mucosa by the absence of epithelial damage in the former. This observation can in part be explained by the predominant location of H. heilmannii at a distance from the epithelium in contrast to the conspicuous H. pylori adhesion to epithelial cells, coupled with a usually low bacterial burden and patchy occurrence of H. heilmannii as opposed to the generally more heavy infestation with H. pylori.

A comparison of Helicobacter pylori and H. heilmannii gastritis. A matched control study involving 404 patients

BACKGROUND

Since Helicobacter heilmannii gastritis is very much rarer than H. pylori gastritis, and no systematic studies comparing these two gastritides have so far been carried out, we undertook the present study to investigate possible differences between H. heilmannii and H. pylori gastritis.

METHODS

In 202 patients with H. heilmannii gastritis and 202 matched control patients with H. pylori gastritis and duodenal ulcer the following variables were graded and compared: Helicobacter colonization, chronicity of gastritis, activity of gastritis, replacement of foveolar epithelium by regenerative epithelium, mucus depletion, frequency of acquired mucosa-associated lymphoid tissue (MALT), and intestinal metaplasia.

RESULTS

In contrast to the diffuse pattern of colonization in the case of H. pylori, colonization with H. heilmannii is mainly (91.2%) focal and for the most part restricted to the antrum (only 29.1% concurrent colonization of the corpus). The gradings of all gastritis variables were statistically highly significantly milder in the case of H. heilmannii gastritis. In addition, intestinal metaplasia and acquired MALT were significantly less common in patients with H. heilmannii infection. The rare cases of erosions (n = 8) and ulcerations (n = 8) in H. heilmannii gastritis were usually associated with the use of non-steroidal anti-inflammatory drugs. In a single case of H. heilmannii gastritis a concurrent gastric carcinoma and in seven cases a low-grade gastric MALT lymphoma were found.

CONCLUSION

In contrast to H. pylori infection the rare colonization of the gastric mucosa with H. heilmannii, mainly circumscribed and mostly in the antrum, induces a very much milder form of gastritis in the antrum and corpus, which may also be the reason for the rarity of concurrent erosions and ulcers. Whether the observed relatively frequent association of H. heilmannii infection and gastric MALT lymphoma is coincidental, and whether H. heilmannii gastritis is more commonly associated with MALT lymphoma than is H. pylori gastritis must be investigated in further studies.

Helicobacter heilmannii (formerly Gastrospirillum hominis) gastritis: an infection transmitted by animals?

BACKGROUND

The source of infection with Helicobacter heilmannii (formerly Gastrospirillum hominis), a relatively rare causative agent of gastritis in humans, is not clear. It has long been known that this organism occurs in the stomach of domestic animals and pets.

METHODS

By performing an epidemiologic investigation on possible contact of patients with Helicobacter heilmannii gastritis with such animals, we made an attempt to gain further information about the source of infection.

RESULTS

Of 125 patients with confirmed H. heilmannii infection, 111 provided us with information about contact with animals. Some 70.3% of the patients had contact with one or more animals (as compared with 37% in the 'normal' population); 73% were males, and 1.6% had concomitant infection with H. pylori.

CONCLUSIONS

Our analysis indicates that H. heilmannii gastritis is due to its transmission to humans by domestic animals or pets. Concomitant infections by H. heilmannii and H. pylori are very rare, and it is possible that H. heilmannii might protect from infection with H. pylori. However, the results of our retrospective analysis will have to be tested against those of a prospective study investigating the day-to-day situation of the individual patients in greater detail and also be compared with patients not infected with H. heilmannii.

Gastrospirillum hominis in asymptomatic, healthy individuals

Gastrospirillum hominis is a spiral-shaped bacterium found in the stomach. It has been implicated as a possible cause of chronic gastritis. We report two cases of G. hominis colonization observed in a series of 175 healthy, asymptomatic volunteers investigated for Helicobacter pylori. None of the volunteers had symptoms or a history of gastrointestinal disease. Both carriers of G. hominis had histological signs of chronic, active antral gastritis. Multiple tests for H. pylori were negative. The prevalence of this spiral bacterium in healthy, asymptomatic individuals may be as low as in symptomatic persons.