Gastric spiral bacilli in captive cheetahs

DETERMINATION OF SPECIFIC ENTEROPATHOGEN PRESENCE IN CAPTIVE CHEETAHS (ACINONYX JUBATUS) FED VARIOUS DIETS USING FLUORESCENCE IN SITU HYBRIDIZATION

Chronic enteropathies pose an important difficulty in the captive management of cheetahs (Acinonyx jubatus) because of suspected multifactorial pathogenesis and the complex nature of enteric microbiota dynamics. Enterobacteriaceae, Campylobacter spp., Clostridium perfringens, Helicobacter spp., and Salmonella spp. are enteropathogens of interest because of their zoonotic potential and suspected contribution to enteropathies. This study aimed to determine the presence of these enteropathogens of interest in fecal samples from cheetahs (N = 48) fed different diets from three different institutions and to investigate the associations between diet, fecal score, and specific enteropathogen presence. Fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes were used to visualize and quantify putative enteropathogens in each sample concurrent with selective culturing for Salmonella and Clostridium perfringens. From FISH counts, carcass-fed animals had greater numbers of Enterobacteriaceae compared with animals fed low-fat dog food, although this trend was not statistically significant (P = 0.088). Furthermore, no significant associations were found between fecal score and bacterial load. Abundance of Campylobacter spp., Clostridium perfringens, or Helicobacter spp. as measured by FISH were not correlated with diet or fecal score. On the basis of these data, in agreement with published literature, it is concluded that these microbes may be commensals in the cheetah gastrointestinal tract and do not appear to be a primary cause of abnormal fecal scores.

Chronic Stress-Related Gastroenteric Pathology in Cheetah: Relation between Intrinsic and Extrinsic Factors

Simple Summary

The cheetah is the fastest land mammal. Habitat destruction, high mortality due to other predators, and illegal wildlife trade has led to a decrease in the wild population. Currently, the global adult population present in their natural habitat is estimated to be 7100 individuals. In captivity, the population suffers from limited reproduction and disease. Both the wild and captive populations have reduced genetic diversity from a historic bottleneck, leading to increased ecological and environmental vulnerability. Over the years, conservation programs have been developed for habitat protection, management of human–animal conflict, and the study of disease and genetics. Among these, the one with the greatest prevalence in captivity is chronic gastritis. This review analyzes the scientific literature on gastric pathology in cheetah, with the potential causes divided into “extrinsic factors”, such as living conditions and diet, and “intrinsic factors”, including the presence of Helicobacter-like organisms and the genetic predisposition.

Abstract

The rapid decline of cheetah (Acinonyx jubatus) throughout their range and long-term studies of captive breeding has increased conservation action for this species including the study of chronic diseases. Gastritis is one of the captive diseases that leads to high mortality presented with symptoms including vomiting, diarrhea, anorexia, and weight loss. The disease presents different histological lesions in the gastrointestinal tract that are characterized by inconstant and different clinical appearance in captive and free-range cheetahs. The aim of this review is to summarize the causes of chronic gastritis in the cheetah. Factors including diet, living conditions, infections with gastric Helicobacter-like organisms (GHLOs), the lack of genetic polymorphism and the cheetah’s specific-immunocompetence are analyzed. All studies on gastroenteric cheetah pathologies, conducted between 1991 (to the best of our knowledge, the first report on online databases) and 2021, are included in this review, highlighting the possible correlation between stress-related captive conditions and chronic gastric pathology.

Gut microbiomes of free-ranging and captive Namibian cheetahs: Diversity, putative functions and occurrence of potential pathogens

Although the significance of the gut microbiome for host health is well acknowledged, the impact of host traits and environmental factors on the interindividual variation of gut microbiomes of wildlife species is not well understood. Such information is essential; however, as changes in the composition of these microbial communities beyond the natural range might cause dysbiosis leading to increased susceptibility to infections. We examined the potential influence of sex, age, genetic relatedness, spatial tactics and the environment on the natural range of the gut microbiome diversity in free-ranging Namibian cheetahs (Acinonyx jubatus). We further explored the impact of an altered diet and frequent contact with roaming dogs and cats on the occurrence of potential bacterial pathogens by comparing free-ranging and captive individuals living under the same climatic conditions. Abundance patterns of particular bacterial genera differed between the sexes, and bacterial diversity and richness were higher in older (>3.5 years) than in younger individuals. In contrast, male spatial tactics, which probably influence host exposure to environmental bacteria, had no discernible effect on the gut microbiome. The profound resemblance of the gut microbiome of kin in contrast to nonkin suggests a predominant role of genetics in shaping bacterial community characteristics and functional similarities. We also detected various Operational Taxonomic Units (OTUs) assigned to potential pathogenic bacteria known to cause diseases in humans and wildlife species, such as Helicobacter spp., and Clostridium perfringens. Captive individuals did not differ in their microbial alpha diversity but exhibited higher abundances of OTUs related to potential pathogenic bacteria and shifts in disease-associated functional pathways. Our study emphasizes the need to integrate ecological, genetic and pathogenic aspects to improve our comprehension of the main drivers of natural variation and shifts in gut microbial communities possibly affecting host health. This knowledge is essential for in situ and ex situ conservation management.

Electron microscopic, genetic and protein expression analyses of Helicobacter acinonychis strains from a Bengal tiger

Colonization by Helicobacter species is commonly noted in many mammals. These infections often remain unrecognized, but can cause severe health complications or more subtle host immune perturbations. The aim of this study was to isolate and characterize putative novel Helicobacter spp. from Bengal tigers in Thailand. Morphological investigation (Gram-staining and electron microscopy) and genetic studies (16SrRNA, 23SrRNA, flagellin, urease and prophage gene analyses, RAPD DNA fingerprinting and restriction fragment polymorphisms) as well as Western blotting were used to characterize the isolated Helicobacters. Electron microscopy revealed spiral-shaped bacteria, which varied in length (2.5-6 µm) and contained up to four monopolar sheathed flagella. The 16SrRNA, 23SrRNA, sequencing and protein expression analyses identified novel H. acinonychis isolates closely related to H. pylori. These Asian isolates are genetically very similar to H. acinonychis strains of other big cats (cheetahs, lions, lion-tiger hybrid and other tigers) from North America and Europe, which is remarkable in the context of the great genetic diversity among worldwide H. pylori strains. We also found by immunoblotting that the Bengal tiger isolates express UreaseA/B, flagellin, BabA adhesin, neutrophil-activating protein NapA, HtrA protease, γ-glutamyl-transpeptidase GGT, Slt lytic transglycosylase and two DNA transfer relaxase orthologs that were known from H. pylori, but not the cag pathogenicity island, nor CagA, VacA, SabA, DupA or OipA proteins. These results give fresh insights into H. acinonychis genetics and the expression of potential pathogenicity-associated factors and their possible pathophysiological relevance in related gastric infections.

Effect of diet on the incidence of and mortality owing to gastritis and renal disease in captive cheetahs (Acinonyx jubatus) in South Africa

Seventy-two adult cheetahs were evaluated for the degree of gastritis by endoscopic biopsy and for renal disease by serum creatinine. Cheetahs free of Grade 3 gastritis and renal disease were placed on Trial A; remaining cheetahs were placed on Trial B, which ran concurrently. All cheetahs were monitored for 4 years. Cheetahs exited Trial A and entered Trial B if they developed Grade 3 gastritis or renal disease. Cheetahs exited Trial B if they developed clinical gastritis or renal disease that required a dietary change or aggressive medical therapy or died owing to either disease. Cheetahs on Trial A were fed either a supplemented meat diet (N = 26) or commercial cat food (N = 22). Cheetahs on Trial B were fed either the same meat diet (N = 28) or a commercial dry cat food formulated for renal disease (N = 16). Cheetahs fed meat on Trial A had a daily hazard of developing Grade 3 gastritis 2.21 times higher (95% CI 0.95-5.15) than cheetahs fed commercial cat food. This hazard was not statistically significant (P = 0.07). Mean gastritis scores were not significantly different between the two groups. Cheetahs fed commercial cat food in both Trials had lower serum urea levels and higher creatinine levels than those fed meat. Evidence for the effect of diet in cheetahs with gastritis and/or renal disease (Trial B) was inconclusive. The number of cheetahs dying of gastritis or renal disease at the facility has dropped markedly since the study began. These results indicate that diet may play an important role in the incidence of Grade 3 gastritis and that dietary and/or therapeutic management of gastritis may reduce mortality owing to gastritis and renal disease in captive cheetahs.

Characterization of the Gastric Immune Response in Cheetahs (Acinonyx jubatus) With Helicobacter-Associated Gastritis

Captive cheetahs have an unusually severe progressive gastritis that is not present in wild cheetahs infected with the same strains of Helicobacter. This gastritis, when severe, has florid lymphocyte and plasma cell infiltrates in the epithelium and lamina propria with gland destruction, parietal cell loss, and, in some cases, lymphoid follicles. The local gastric immune response was characterized by immunohistochemistry in 21 cheetahs with varying degrees of gastritis. The character of the response was similar among types of gastritis except that cheetahs with severe gastritis had increased numbers (up to 70%) of lamina proprial CD79a+CD21– B cells. CD3+CD4+ T cells were present in the lamina propria, and CD3+CD8α+ T cells were within the glandular epithelium. Lymphoid aggregates had follicular differentiation with a central core of CD79a+/CD45R+ B cells and with an outer zone of CD3+ T cells that expressed both CD4 and CD8 antigens. MHC II antigens were diffusely expressed throughout the glandular and superficial epithelium. No cheetah had evidence of autoantibodies against the gastric mucosa when gastric samples from 30 cheetahs with different degrees of gastritis were incubated with autologous and heterologous serum. These findings indicate that T-cell distribution in cheetahs is qualitatively similar to that in other species infected with Helicobacter but that large numbers of lamina propria activated B cells and plasma cells did distinguish cheetahs with severe gastritis. Further research is needed to determine whether alterations in the Th1:Th2 balance are the cause of this more plasmacytic response in some cheetahs.

Reproduction of severe gastroesophageal ulcers (GEU) in gnotobiotic swine infected with porcine Helicobacter pylori-like bacteria

Groups of gnotobiotic piglets were orally inoculated at 3 days of age with either Helicobacter heilmannii (Hh) or a newly described porcine-origin gastric Helicobacter pylori (Hp)-like bacterium. Three Hh-infected and 6 porcine Hp-like-infected swine were fed a milk replacement diet containing 5-10% (v/v) sterile corn syrup as a dietary source of fermentable carbohydrate. None of the piglets infected with Hh and supplemented with corn syrup developed gastric mucosal ulcers; 2 developed small erosive lesions in the pars esophagea. In contrast, all 6 dietary carbohydrate-supplemented Hp-like-infected swine developed severe gastroesophageal ulcers; 1 of these ex-sanguinated into the stomach and died before the end of the experiment. Four of these 6 piglets had grossly evident partially digested blood in the intestinal lumens, indicative of bleeding into the gastrointestinal tract from the stomach. These data suggest that a high carbohydrate diet and gastric colonization by porcine Hp-like bacteria facilitate development of clinically significant gastroesophageal ulcers.

EFFICACY AND LONG-TERM OUTCOME OF GASTRITIS THERAPY IN CHEETAHS (ACINONYX JUBATUS)

A prospective clinical trial evaluating efficacy and long-term outcome of treatments for lymphoplasmacytic gastritis in cheetahs (Acinonyx jubatus) was conducted. The study evaluated efficacy of 11 different antibiotic and antiinflammatory treatment protocols in 32 cheetahs (19 male, 13 female) for reducing gastric inflammation and Helicobacter colonization and monitored the course of disease through histologic grading of gastric biopsies. All cheetahs were biopsied up to I wk before treatment and then rebiopsied within 1 mo after treatment. Most animals were reassigned to a second treatment regimen within 6 mo. Each animal received from one to three treatments during the study period. After the trial, gastric biopsies were obtained from each cheetah annually until death or transfer from the facility to assess disease progression. The trial and follow-up period spanned 10 yr. At onset of the trial, all 32 cheetahs had some degree of gastritis, and 26 cheetahs (81%) were colonized with Helicobacter. Inflammatory lesions worsened regardless of treatment or the presence of Helicobacter. No treatment had a significant effect on inflammatory changes except the lansoprazole/clarithromycin/amoxicillin treatment group, which produced a short-term decrease in inflammation when compared to controls. Prednisone had no effect on gastric inflammation. Overall, 65% of colonized cheetahs were initially cleared of histologic evidence of Helicobacter by treatment, with short-term eradication occurring in 100% of the animals treated with omeprazole/clarithromycin/amoxicillin or tetracycline/metronidazole/Pepto-Bismol for 28 days. Long-term follow-up of treated animals in this study clearly demonstrated that these treatments had little effect on life-long progression of gastritis or on Helicobacter burden in individual cheetahs, although some treatments provided short-term reduction in gastritis and Helicobacter. These results provide evidence that Helicobacter alone is not the cause of gastritis in cheetahs and do not support the use of antibacterial treatments in cheetahs unless significant clinical signs (e.g., frequent vomiting/regurgitation, weight loss) are apparent.

Isolation and preliminary characterization of a novel Helicobacter species from swine

OBJECTIVE

To determine whether a Helicobacter sp similar to Helicobacter pylori in the stomachs of humans could be isolated from the stomachs of pigs.

ANIMALS

4 young conventionally reared and 21 gnotobiotic pigs.

PROCEDURE

Gastric mucosal homogenates (10% wt/vol) from 4 young conventionally reared pigs were cultured on Skirrow medium under microaerophilic conditions to assess the presence of Helicobacter spp. Colonies with morphologic features compatible with Helicobacter organisms were selected, tested for urease activity, and subpassaged on Skirrow medium. Isolates were examined via SDS-PAGE electrophoresis and reciprocal western blot analyses involving convalescent sera from monoinfected gnotobiotic pigs.

RESULTS

Urease- and catalase-positive, gram-negative, microaerophilic, small, curved rod bacteria were isolated from the gastric mucosa of young healthy pigs. The first isolate (2662) was structurally and immunologically closely related to H pylori isolated from humans. The second isolate (1268) displayed an SDS-PAGE profile dissimilar to that of H pylori and isolate 2662, yet it shared limited immunologic cross-reactivity with these microbes.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings of this study indicate that development of gastric mucosal ulcers and ulceration of the nonglandular pars esophagea in pigs may be associated with gastric colonization by swine-origin Helicobacter spp, which are similar to H pylori isolated from humans.

Experimental induction of bacterial gastritis and gastric ulcer disease in gnotobiotic swine inoculated with porcine Helicobacter-like species

OBJECTIVE

To determine whether 2 isolates of recently isolated swine-origin Helicobacter pylori-like bacteria are pathogenic in pigs and compare the signs of gastric disease induced by these isolates with those detected in H pylori- and Helicobacter heilmannii-infected pigs.

ANIMALS

36 neonatal gnotobiotic pigs.

PROCEDURE

Groups of separately housed pigs were inoculated orally with swine-origin Helicobacter-like isolates 2662 or 1268, H pylori (human gastric pathogen), or a gastric homogenate from gnotobiotic swine containing H heilmannii. Noninoculated pigs were used as control animals. Clinical signs and development of homologous and heterologous antibodies against Helicobacter organisms were assessed. After euthanasia, gastric tissues were examined grossly and microscopically; Helicobacter organisms were detected by use of Warthin-Starry and immunohistochemical stains.

RESULTS

Both porcine Helicobacter-like isolates colonized the stomachs of swine. Isolate 2662 was highly pathogenic; in 13 isolate 2662-inoculated pigs, gastroesophageal ulcerations developed in 9 and ulceration of the gastric glandular mucosa was detected in 5. Histologically, inflammatory gastritis consisting of multifocal to diffuse lymphocytic and plasmacytic cellular infiltrates and lymphoid follicle formation in the gastric lamina propria accompanied bacterial colonization of the gastric compartment. In contrast, H heilmannii was minimally pathogenic in that only modest inflammatory cell infiltrates were seen. Gastroesophageal or mucosal ulcers were not evident in pigs inoculated with H heilmannii.

CONCLUSIONS AND CLINICAL RELEVANCE

These data indicate that swine-origin H pylori-like bacteria can be pathogenic in pigs and suggest that porcine gastric disease may be mediated, in part, by colonization of the stomach by swine-origin H pylori-like bacteria.

Comparison of Helicobacter spp. in Cheetahs (Acinonyx jubatus) with and without gastritis

Chronic gastritis causes significant morbidity and mortality in captive cheetahs but is rare in wild cheetahs despite colonization by abundant spiral bacteria. This research aimed to identify the Helicobacter species that were associated with gastritis in captive cheetahs but are apparently commensal in wild cheetahs. Helicobacter species were characterized by PCR amplification and sequencing of the 16S rRNA, urease, and cagA genes and by transmission electron microscopy of frozen or formalin-fixed paraffin-embedded gastric samples from 33 cheetahs infected with Helicobacter organisms (10 wild without gastritis and 23 captive with gastritis). Samples were screened for mixed infections by denaturant gel gradient electrophoresis of the 16S rRNA gene and by transmission electron microscopy. There was no association between Helicobacter infection and the presence or severity of gastritis. Eight cheetahs had 16S rRNA sequences that were most similar (98 to 99%) to H. pylori. Twenty-five cheetahs had sequences that were most similar (97 to 99%) to "H. heilmannii" or H. felis. No cheetahs had mixed infections. The ultrastructural morphology of all bacteria was most consistent with "H. heilmannii," even when 16S rRNA sequences were H. pylori-like. The urease gene from H. pylori-like bacteria could not be amplified with primers for either "H. heilmannii" or H. pylori urease, suggesting that this bacteria is neither H. pylori nor "H. heilmannii." The cagA gene was not identified in any case. These findings question a direct role for Helicobacter infection in the pathogenesis of gastritis and support the premise that host factors account for the differences in disease between captive and wild cheetah populations.

Validation of the 13C-urea breath test for use in cheetahs (Acinonyx jubatus) with Helicobacter

Historically, therapeutic monitoring for prescribed eradication treatment of Helicobacter in cheetahs (Acinonyx jubatus) with associated gastritis has been accomplished only through endoscopic biopsies. The 13C-urea breath test (UBT) can offer an alternative to repeated biopsies for therapeutic monitoring. Five male and five female cheetahs and one male Sumatran tiger (Panthera tigris) were studied. All were clinically healthy before and after this investigation. Breath samples of end-tidal expiration were taken before and after administration of a 13C-enriched urea solution through a gastroesophageal tube. Twenty-milliliter breath samples were taken at 10, 20, 30, and 40 min after administration of the urea solution. The results of the breath analysis were compared with the results of rapid urease testing, histopathologic examination, and impression smears of gastric biopsies taken at the time of the breath test. The sensitivity and specificity for the 13C-UBT in this investigation were 100%. and the positive predictive value and negative predictive value were both 100%. Although the 13C-UBT is a good noninvasive diagnostic tool for monitoring the presence of Helicobacter sp. in the gastric mucosa, endoscopy should still be used for initial diagnosis and grading of gastritis and for monitoring the progression of disease in cheetahs. The 13C-UBT is a valuable, simple, accurate, and sensitive tool for monitoring eradication of Helicobacter during therapy for clinical gastritis.

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.

Porcine gastric ulcer

Ulceration of the pars esophagea in swine develops from a complex interaction of dietary particle size, gastric fluidity, dietary carbohydrate content, and presence of certain species of commensal gastric organisms capable of fermenting dietary carbohydrates. Unlike in humans, the significance of the role of Helicobacter sp. in development of porcine gastric ulcers is yet undefined. Management practices that limit the incidence and severity of gastric ulceration without interfering with growth performance appear to be the best option for control.

Healthy cats are commonly colonized with "Helicobacter heilmannii" that is associated with minimal gastritis

Gastric Helicobacter infection in healthy pet cats is not well characterized. We performed endoscopy with gastric biopsy on 15 healthy pet cats that were rigorously screened to exclude underlying or concurrent diseases that might affect Helicobacter colonization. Gastric mucosa biopsy specimens were examined by histology, culture, and PCR for the presence of Helicobacter infection and by histology for the presence of gastritis. Of 15 cats, all but 1 had gastric Helicobacter-like organisms (GHLOs) on examination by light microscopy, and in the one histologically negative cat, GHLOs were detected by PCR. Gastric inflammation was mild or was absent for all cats. No Helicobacter species were identified by culture. Analysis of the 16S rRNA sequence from Helicobacter strains from 10 cats showed that all bacteria were closely related to Helicobacter felis, although there was heterogeneity among the sequences. These results suggest that the gastric mucosa of healthy pet cats is commonly colonized with an uncultivated Helicobacter that is closely related to H. felis, is associated with little or no gastritis, and shows heterogeneity in its 16S rRNA sequence. The epithet "Helicobacter heilmannii" continues to be an appropriate working designation for these bacteria.

Production of gastroesophageal erosions and ulcers (GEU) in gnotobiotic swine monoinfected with fermentative commensal bacteria and fed high-carbohydrate diet

Erosions and gastroesophageal ulcers (GEU) were produced in the pars esophagea of young gnotobiotic swine fed a carbohydrate-enriched liquid diet and monoinfected with two different fermentative commensal bacteria, Lactobacillus and Bacillus sp. In contrast, piglets, fed a similar diet and inoculated with Gastrospirillum sp. (Helicobacter heilmannii), a helicobacter species that colonizes the gastric mucosa, did not develop GEU. Experimental GEU likely develops secondary to epithelial damage mediated by microbial-origin acids whose production is potentiated by high dietary carbohydrate and parietal cell-origin hydrochloric acid.

Demonstration of Helicobacter pylori-like organisms in the gastric mucosa of captive exotic carnivores

Samples of gastric tissue from the cardiac, fundic and pyloric region of 30 carnivores comprising 12 tigers (Panthera tigris), 10 lions (Panthera leo), three pumas (Felis concolor), two leopards (Panthera pardus), one serval (Felis serval), one wolf (Canis lupus) and one hyena (Crocuta crocuta) kept at German zoological gardens were subjected to histopathological and immunohistochemical examination. Selected tissue specimens of 12 animals were examined also by electron microscopy. The purpose of this study was to determine the prevalence of Helicobacter-like organisms in carnivores and to record infection rates, degree of colonization and associated histopathological changes. Three morphologically different types of spiral-shaped bacteria were demonstrated. A Helicobacter pylori-like organism (HPLO) was found in 42% of the tigers and 90% of the lions examined. Large Helicobacter-like organisms (HLOs) were identified in three pumas, one serval, one hyena and in three lions (in the latter, in coexistence with HPLOs). A third organism with a spiral periplasmic fibril (Helicobacter felis-like) was demonstrated in a wolf. The most striking histopathological finding associated with HPLO and HLO colonization was the formation of lymphoid follicles in the mucosa. Additional lymphoplasmacytic and neutrophilic infiltrates in the gastric mucosa were found in a number of tigers and lions infected with HPLOs, but none in the other carnivores infected with HLOs. From these results it is concluded that gastric bacteria similar or identical with H. pylori may also be an important cause of chronic gastritis in tigers and lions.

Lipid profile of Helicobacter spp.: presence of cholesteryl glucoside as a characteristic feature

The lipid and fatty acid profiles of eight Helicobacter spp. (H. nemestrinae, H. acinonyx, H. canis, Helicobacter sp. strain CLO-3, "H. rappini" [Flexispira rappini], H. pametensis, Helicobacter sp. strain Bird-B, and Helicobacter sp. strain Bird-C) and the fatty acid profiles of five additional species (H. pylori, H. felis, H. muridarum, H. mustelae, and H. fennelliae) were analyzed and compared. A heterologous fatty acid profile was observed among the Helicobacter spp., and on that basis the species could be divided into two groups. Group A had 19-carbon cyclopropane fatty acid (19:0cyc) and tetradecanoic acid (14:0) as the major fatty acids, and group B characteristically lacked the 19:0cyc and had hexadecanoic acid (16:0) and octadecenoic (18:1) acids as the major fatty acids. The species of group A are primarily gastric colonizers, and those of group B are primarily intestinal colonizers. Seven of the eight species studied showed the unusual and characteristic presence of cholesteryl glucosides (CGs), and most of these seven showed a very large amount (9.7 to 27.4% of the weight of total extractable lipid). The types of CGs and their distribution in different species were as follows: cholesteryl-6-O-acyl-alpha-D-glucopyranoside (cholesteryl-6-O-tetradecanoyl-alpha-D-glucopyranoside in H. nemestrinae and mainly cholesteryl-6-O-dodecanoyl-alpha-D-glucopyranoside in "H. rappini"), cholesteryl-alpha-D-glucopyranoside (H. nemestrinae, H. acinonyx, H. canis, Helicobacter sp. strain CLO-3, and "H. rappini"), and cholesteryl-6-O-phosphatidyl-alpha-D-glucopyranoside (H. nemestrinae, H. acinonyx, H. canis, and Helicobacter sp. strain CLO-3). Besides this, we could also detect cholesteryl acyl glucoside in H. acinonyx, cholesteryl glucoside in Helicobacter sp. strains Bird-B and -C, and cholesteryl phosphatidyl glucoside in "H. rappini" and Helicobacter sp. strain Bird-C. A selective accumulation of free cholesterol was observed in the neutral lipid fractions. On the basis of the detection of CGs in 11 of the 13 species studied so far, the presence of CGs appears to be a characteristic feature of the genus Helicobacter. In view of this and also because of a simple and rapid detection method described herein, the CGs can be used as a valuable chemotaxonomic marker.

Animal models and vaccine development

Following the demonstration of Helicobacter pylori as a major gastroduodenal pathogen there was a need to develop animal models in order to investigate mechanisms of pathogenesis and to be able to test new treatment strategies. Helicobacter pylori will only colonize a limited number of hosts including non-human primates, germ-free or barrier raised piglets, germ-free dogs and recently laboratory raised cats. Although these models have proved useful there is a need for more convenient small animal models. The ferret infected with its natural gastric organism, Helicobacter mustelae, is the only other animal to show peptic ulceration and has been successfully used to investigate gastritis and antimicrobial agents. The other commonly used animal model is the laboratory mouse or rat infected with either Helicobacter felis or Helicobacter heilmannii, bacteria that normally colonize cat or dog gastric mucosae. Active/chronic gastritis, gastric atrophy, and lymphoma-like lesions have been shown to develop in H. felis infected mice. The most recent and exciting use of an animal model has been the use of the H. felis mouse model in the development of human vaccines against H. pylori. Mice can be protected against infection with large doses of viable H. felis by oral immunization using sonicates of H. felis or H. pylori or recombinant H. pylori urease together with cholera toxin or cholera toxin-B subunit as the mucosal adjuvant. More importantly it has been shown that immunization of already infected animals results in eradication of infection. This raises the intriguing possibility that therapeutic immunization might be a viable option in the management of Helicobacter-associated disease. If immunization as a therapy of peptic ulcers was combined with short-term acid suppression, the possibility of reinfection may also be eliminated. In those countries where H. pylori infection rates are very high and infection occurs at an early age, large scale oral immunization of sections of the community would not only protect the young from the deleterious consequences of long-term H. pylori infection but could also cure existing disease.

Gastrospirillum hominis-associated chronic active gastritis

A 16-year-old Caucasian male presented with nausea, vomiting, and abdominal pain. Endoscopy revealed erythematous antral mucosa with four discrete gastric ulcers. Biopsies showed multiple spiral organisms, 4-6 microns in length, lying in the mucous layer on the surface. The organisms were strongly Giemsa positive and weakly CLOtest positive. They did not stain with Warthin-Starry silver or Gram-Weigert stains. Electron microscopy revealed fragments of Gastrospirillum hominis, with its characteristic spiral shape and length of 4 microns in the plane of section. We believe that this is one of the first reported pediatric cases in North America.

Helicobacter-like organisms: histopathological examination of gastric biopsies from dogs and cats

Gastric biopsies from the fundic gland region of 122 dogs and 127 cats were subjected to histopathological examination. The aim of the study was to determine infection rates and degrees of colonization by Helicobacter-like organisms (HLOs), and to ascertain their possible relationship to histopathological changes. In all, 82% of the dogs and 76% of the cats had an HLO infection. The most striking histopathological changes were glandular degeneration with accumulation of lymphocytes and neutrophilic granulocytes (dogs, 21%; cats, 39%), fibrosis of the lamina propria mucosae (dogs, 41%; cats, 58%), oedema in the lamina propria mucosae (dogs, 54%; cats, 23%), lymphoid follicles (dogs, 17%; cats, 19%) and lymphoplasmacytic infiltrates. A relation between the degree of colonization by HLOs and the extent of histopathological changes could only be discovered in the cats. It was not possible to ascertain whether these bacteria, irrespective of the degree of colonization, were responsible for the histopathological changes in the dogs.

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.

Acute gastritis associated with spiral organisms from cats

Numerous studies implicated Helicobacter pylori as one causative agent producing gastritis and dyspepsia. Recent reports focus on another bacterium, Gastrospirillum hominis, as a possible pathogen producing gastritis. We report a 30-year-old researcher who became acutely ill with epigastric pain indicative of esophagitis or peptic ulcer disease. Gastritis and a gastric ulcer were observed endoscopically. Histological examination of the gastric mucosa revealed an acute gastritis and large spiral-shaped organisms. The spiral forms were present in large quantities in the gastric mucosa of experimental animals (cats) handled by the patient in his research. Electron microscopy confirmed that the organisms from the cat and patient were morphologically identical. The patient was successfully treated with bismuth subsalicylate. His symptoms resolved and the organisms were cleared from his stomach. This study provides evidence that another bacterium, a Gastrospirillum, may cause gastritis in man and may be transmitted from animal to man.

Epizootic gastritis associated with gastric spiral bacilli in cheetahs (Acinonyx jubatus)

An outbreak of vomiting in a group of captive cheetahs (Acinonyx jubatus) was investigated, and histologic examination revealed chronic gastritis characterized by infiltration of lymphocytes and numerous plasma cells and epithelial erosions. Lymphoid follicles, globule leukocytes, scattered neutrophils, and (in one animal) abscessed gastric glands were inconsistent findings. In addition, necropsy of three cheetahs revealed gastric mucosal hyperplasia. Two kinds of bacteria were identified in the stomachs of infected cheetahs. Numerous long, tightly coiled motile Gastrospirillum-like organisms were seen in gastric mucus and in Warthin-Starry-stained sections of mucosa. These bacteria could not be cultured but were transmitted to conventional mice in homogenates of gastric mucosa from infected cheetahs. Ultrastructural examination revealed helical filaments on some of these bacteria. In addition, a smaller Helicobacter sp. was isolated. This organism could be cultured in vitro under microaerophilic conditions. One or both of these bacterial species was probably responsible for the gastritis in these cheetahs.