New spiral bacterium in gastric mucosa

Transmission of Helicobacter spp. A challenge to the dogma of faecal-oral spread

Faecal oral spread is claimed by many to be the mode of transmission of the gastric pathogen Helicobacter pylori. This idea is based not on experimental data but because the epidemiology of H. pylori infection resembles that of other pathogens known to be spread by the faecal-oral route. This is in spite of the observation that no-one has been successful in culturing H. pylori from human stool. In this study, a series of transmission experiments are reported on animals infected with the gastric spirilla, Helicobacter felis and 'Gastrospirillum hominis'. Germfree mice and rats infected with H. felis did not transmit their infection to uninoculated mice despite prolonged contact in the same cage nor could the bacterium be isolated from their intestinal contents. This was confirmed in specific pathogen free mice where infected dams did not pass the helicobacter to their progeny. Similarly, mice infected with a human isolate of 'Gastrospirillum hominis' did not transmit the infection while in close contact with uninoculated mice. In contrast, in a limited series of experiments, both H. pylori and H. felis were transmitted from infected gnotobiotic Beagle puppies to uninfected animals in the same enclosure. In addition, the gastric mucus from a cat with indigenous 'Gastrospirillum'-like organisms was infectious for mice, whereas faecal content from the same animal was not. It is suggested that the difference between the murine and canine experiments is that the dogs are more likely to have oral-oral contact than rodents. Unlike dogs, mice and rats do not vomit and are coprophagous. It is concluded that the case for faecal-oral spread of Helicobacter species is 'not proven' and that the inter-oral route is more likely.

Helicobacter mustelae-induced gastritis and elevated gastric pH in the ferret (Mustela putorius furo)

Helicobacter mustelae has been cultured from the stomachs of ferrets with chronic gastritis; the lesions in the stomach have many of the same histological features seen in H. pylori gastritis in humans. To determine whether H. mustelae-negative ferrets with normal gastric mucosa were susceptible to colonization and whether gastritis developed after infection, four H. mustelae-negative ferrets treated with cimetidine were inoculated orally on two successive days with 3 ml (1.5 x 10(8) CFU) of H. mustelae; eight age-matched H. mustelae-negative ferrets served as controls. All four ferrets became colonized; H. mustelae persisted through week 24 of the study, as determined by positive gastric culture, tissue urease, and Warthin-Starry staining of gastric tissue. Superficial gastritis developed in the oxyntic gastric mucosa, and a full-thickness gastritis, composed primarily of lymphocytes and plasma cells plus small numbers of neutrophils and eosinophils, was present in the antrum. The inflammation was accompanied by an elevation of immunoglobulin G antibody to H. mustelae. At 4 weeks post-inoculation, the four infected (experimental) ferrets developed an elevated gastric pH (4.0 to 5.2) for 2 weeks. The eight control ferrets did not have gastritis; H. mustelae could not be demonstrated in gastric tissue via culture, nor was there an immune response to the bacteria. In ferrets, H. mustelae readily colonizes the stomach and produces a gastritis, a significant immune response, and, like H. pylori infection in humans, a transient elevated gastric pH after Helicobacter infection.

Gastric injury and invasion of parietal cells by spiral bacteria in rhesus monkeys. Are gastritis and hyperchlorhydria infectious diseases?

The possibility of using the rhesus monkey as a model for studying gastric function in the presence of infection with spiral bacteria was studied. Endoscopic evaluation of the gastric mucosa was performed under general anesthesia in 29 colony-bred rhesus monkeys, and gastric pinch biopsy specimens were obtained from each animal. On a separate day, gastric emptying and acid output were determined using a 99mTc dilution technique. Biopsy samples were fixed for light microscopy (H&E, Gram, and Warthin-Starry stains) and for transmission electron microscopy. The presence of spiral bacteria and gastritis was assessed and rated on coded slides. In 8 of 29 monkeys, Helicobacter pylori-like organisms were observed in close proximity to the mucosal epithelial cells or in the lumen of the gastric pits. In 14 other monkeys, "Gastrospirillum hominis"-like organisms were observed in the mucus covering the surface of epithelial cells, in the lumina of the gastric glands, and overlying parietal cells. Gastritis was present in 8 of 8 animals positive for H. pylori-like organisms, in 2 of 14 animals positive for "G. hominis"-like organisms, and in none of the uninfected monkeys, and the mean gastritis index was significantly greater in animals positive for H. pylori-like organisms. Moreover, acid output was significantly higher in monkeys positive for "G. hominis"-like organisms than in controls or animals positive for H. pylori-like organisms. Gastric emptying was not significantly different in the three groups. In conclusion, (a) H. pylori-like, but not "G. hominis"-like, organisms cause gastritis while not modifying acid output; (b) "G. hominis"-like, but not H. pylori-like organisms, invade and on occasion damage parietal cells while apparently causing hyperchlorhydria; and (c) the rhesus monkey appears to be a good model for the study of gastric infection with spiral bacteria.

Transport conditions and number of biopsies necessary for culture of Helicobacter pylori

Stuart's transport medium with a charcoal impregnated swab was tested for transport of biopsies from the gastric antrum for culture of Helicobacter pylori. Biopsies were cultured under microaerophilic conditions either within 2 h or after a delay of 24 h at 4 degrees C. In 65 patients referred for gastroscopy two biopsies were taken. Helicobacter pylori was found in 39 patients. The rate of survival of Helicobacter pylori was found to be as high in Stuart's transport medium after 24 h at 4 degrees C as in the paired biopsy which was cultured immediately after transportation in normal saline. In five (13%) of 39 patients positive for Helicobacter pylori, the organism was cultured from only one of the biopsies. It is therefore recommended that two biopsies be taken for culture.

Gastritis due to spiral shaped bacteria other than Helicobacter pylori: clinical, histological, and ultrastructural findings

An intensive histological search for Helicobacter pylori in gastric biopsy specimens has led to the detection of other spiral shaped bacteria in the human gastric mucosa. The clinical and morphological findings of 39 cases (0.25% of all gastric biopsies performed in the observation period) are reported for 34 patients (87.2%) complaining of upper abdominal discomfort. Five patients (12.8%) had chronic gastritis and 34 (87.2%) chronic active gastritis. The organisms were seen by light microscopy deep in the gastric foveolae and intracellularly. The scanning and transmission electron microscopic findings show bacteria which invade and damage gastric mucosal cells. These organisms are similar to the spiral shaped bacteria found in the stomachs of cats and dogs and non-human primates. In eight patients organisms were not detected after four weeks of treatment with bismuth salts. The disappearance of the organisms coincided with resolution of the chronic active gastritis and the symptoms.

Spiral organisms: what are they? A microbiologic introduction to Helicobacter pylori

The stomach provides a hostile environment to most microorganisms owing to the antibacterial effect of gastric acidity. However, over the period of mammalian evolution a highly specialized group of bacteria has evolved to inhabit the gastric mucosa. The common features of these bacteria that allow survival in the stomach and colonization of their natural ecologic niche, mucus, are a specialized form of motility, microaerophilism, and very high activity of the enzyme urease. Other important adaptations have been the acquisition of sophisticated mechanisms to evade host defences, and in certain cases tissue damage may result. The most important of these usually spiral-shaped bacteria is Helicobacter pylori. It is proposed that this bacterium is the human gastric spirillum that in most persons lives in harmony with its natural host, resulting in asymptomatic infection. However, if as yet undefined conditions are present, serious disease may result-that is, peptic ulceration. A consequence of long-term infection may be atrophic gastritis, which sets the scene for gastric carcinoma. The more the microbiology of the stomach is studied, the more species of Helicobacter are discovered, such as H. mustelae in the ferret, H. felis in cats and dogs, and 'Gastrospirillum hominis' in primates, cats, dogs, and pigs. These other helicobacters provide us with a wide spectrum of animal models of gastroduodenal disease. To understand mechanisms of pathogenesis, it is suggested that systematic study of all members of the genus will identify important colonizing factors and provide a realistic perspective on the putative virulence factors that have been proposed for H. pylori to date.

Gastric spiral bacilli in captive cheetahs

Two kinds of gastric spiral bacilli were identified in the stomachs of captive cheetahs with naturally occurring gastritis. One type was morphologically similar to 'Gastrospirillum hominis'. This organism could not be cultured in vitro. Some of these bacteria had superficial helical filaments, and others did not. The other type was morphologically, biochemically, and bacteriologically similar to Helicobacter pylori. This organism is most likely a new species of Helicobacter. One or both of these bacteria may have been responsible for the gastritis seen in these cheetahs.

Helicobacter pylori-related gastroduodenal disease in children. Diagnostic utility of enzyme-linked immunosorbent assay

To evaluate the accuracy of IgG and IgA serological tests in establishing a diagnosis of Helicobacter (Campylobacter) pylori gastric infection, 60 children presenting with chronic abdominal pain were prospectively studied. Endoscopic antral biopsies were obtained and analyzed for the presence of H. pylori using three standard methods: culture and identification of bacterial isolates, microscopic examination for morphologically characteristic bacteria, and urease production by the biopsy specimen. Concomitantly obtained serum samples were analyzed for the presence of IgG and IgA antibodies against H. pylori surface antigens using enzyme-linked immunosorbent assay (ELISA). Thirty-four of 60 (56.6%) had histological evidence of chronic active gastritis, eight of whom (13.3%) also had evidence of H. pylori infection by at least one criteria. Six of the eight infected patients had H. pylori demonstrated by all three methods. Of the eight infected patients, seven had IgG antibodies against H. pylori (sensitivity of 87%) and six had IgA antibodies (sensitivity of 75%). Among the six patients who had H. pylori infection confirmed by all three methods, all had IgG antibodies (sensitivity of 100%). In the patients without evidence of H. pylori infection, the IgG ELISA had a specificity of 96% (50/52), and the IgA ELISA had a specificity of 100% (52/52). Our data suggest that serological testing for the presence of antibodies against H. pylori may be a useful diagnostic tool in screening children with chronic abdominal pain for the presence of gastric infection with H. pylori.

Immunocytochemical detection of Helicobacter pylori in formalin fixed tissue biopsy specimens

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Evaluation of 3-fucosyl N-acetyllactosamine antibody staining in histological assessment of CIN

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Tightly spiral shaped bacteria in the human stomach: another cause of active chronic gastritis?

Tightly spiral shaped Gram negative bacteria were seen in the gastric biopsies obtained from two patients undergoing gastroscopy. Active chronic gastritis was present in both patients and one patient also had gastric ulceration. Attempts to culture the organism by a number of methods were unsuccessful but positive urease results were obtained in both patients. Both patients were treated with colloidal bismuth subcitrate. Biopsies taken after treatment showed resolution of infection and histological gastritis. These results suggest that Helicobacter pylori is not the only organism associated with chronic active gastritis in man.

Spiral shaped bacteria in gastric mucosa

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'Corkscrew-like' bacteria associated with gastritis

Gastric spiral bacteria morphologically unlike Campylobacter pylori have recently been described in patients with gastritis. We report an additional case. These organisms are as yet unnamed, remain uncultured and are morphologically similar to organisms present in the gastric mucosa of various mammalian species. Their possible role in the pathogenesis of gastritis is discussed.