Study on the role of gastric Helicobacter infection in gross pathological and histological lesions of the stomach in finishing pigs

Incidences of Helicobacter infection in pigs and tracing occupational hazard in pig farmers

Helicobacter species (spp.) is a gram-negative spiral-shaped motile bacterium that causes gastritis in pigs and also colonizes in the human stomach. The present study assessed the prevalence of Helicobacter spp. in pig gastric mucosa and the stool of pig farmers in Assam, India. A total of 403 stomach samples from pig slaughter points, 74 necropsy samples of pigs from pig farms, and 97 stool samples from pig farmers were collected. Among the pig stomach samples, 43 (20.09%) of those with gastritis showed the presence of Gram-negative, spiral-shaped organisms, while only 3.04% of stomach samples without lesions had these organisms. Scanning Electron Microscopy (SEM) of urease-positive stomach samples revealed tightly coiled Helicobacter bacteria in the mucus lining. Histopathological examination showed chronic gastritis with hemorrhagic necrosis, leucocytic infiltration, and lymphoid aggregates. PCR confirmed the presence of Helicobacter suis in 19.63% of pig stomach samples and 2.08% of pig farmer stool samples. Additionally, 3.12% of the stool samples from pig farmers were positive for Helicobacter pylori. Phylogenetic analysis revealed distinct clusters of Helicobacter suis with other Helicobacter spp. These findings highlight the prevalence of Helicobacter in both pig gastric mucosa and pig farmer stool. The findings highlight the need for improved sanitation and hygiene practices among pig farmers to minimize the risk of Helicobacter infection in humans.

A novel method for isolation and culture of primary swine gastric epithelial cells

BACKGROUND

Culturing primary epithelial cells has a major advantage over tumor-derived or immortalized cell lines as long as their functional phenotype and genetic makeup are mainly maintained. The swine model has shown to be helpful and reliable when used as a surrogate model for human diseases. Several porcine cell lines have been established based on a variety of tissues, which have shown to extensively contribute to the current understanding of several pathologies, especially cancer. However, protocols for the isolation and culture of swine gastric epithelial cells that preserve cell phenotype are rather limited. We aimed to develop a new method for establishing a primary epithelial cell culture from the fundic gland region of the pig stomach.

RESULTS

Mechanical and enzymatic dissociation of gastric tissue was possible by combining collagenase type I and dispase II, protease inhibitors and antioxidants, which allowed the isolation of epithelial cells from the porcine fundic glands showing cell viability > 90% during the incubation period. Gastric epithelial cells cultured in RPMI 1640, DMEM-HG and DMEM/F12 media did not contribute enough to cell adhesion, cluster formation and cell proliferation. By contrast, William's E medium supplemented with growth factors supports confluency and proliferation of a pure epithelial cell monolayer after 10 days of incubation at 37 °C, 5% CO2. Mucin-producing cell phenotype of primary isolates was confirmed by PAS staining, MUC1 by immunohistochemistry, as well as the expression of MUC1 and MUC20 genes by RT-PCR and cDNA sequencing. Swine gastric epithelial cells also showed origin-specific markers such as cytokeratin cocktail (AE1/AE3) and cytokeratin 18 (CK-18) using immunohistochemical and immunofluorescence methods, respectively.

CONCLUSIONS

A new method was successfully established for the isolation of primary gastric epithelial cells from the fundic gland zone through a swine model based on a combination of tissue-specific proteases, protease inhibitors and antioxidants after mechanical cell dissociation. The formulation of William's E medium with growth factors for epithelial cells contributes to cell adhesion and preserves functional primary cells phenotype, which is confirmed by mucin production and expression of typical epithelial markers over time.

The role of infectious agents in the development of porcine gastric ulceration

Ulceration of the non-glandular part of the stomach is a common disease entity of pigs worldwide, with prevalences of up to 93%. It may result in decreased daily weight gain, decreased feed intake and sudden death, thus leading to significant economic losses, as well as animal welfare issues. The aetiology is multifactorial. Diet particle size, management and infectious agents have been hypothesised to be involved. The exact mechanism behind porcine gastric ulceration is, however, not completely clear. The aim of this article is to provide an overview of the role of infectious agents in the development of porcine gastric ulceration. Results of recent studies indicate that Helicobacter suis infection plays an important role in gastric ulceration, probably by affecting gastric acid secretion through alteration of the number and/or function of parietal, D and G cells. In a gastric environment altered by H. suis, higher numbers of Fusobacterium gastrosuis are present and this novel pathogen has a potential role in the development of porcine gastric ulceration. Inoculation of pigs with Lactobacillus sp., Bacillus sp. or Helicobacter pylori-like bacteria in combination with a carbohydrate-rich diet may induce gastric lesions. It has been hypothesised that production of short chain fatty acids by some of these bacteria might be involved in the pathogenesis of porcine gastric ulceration, but the lack of taxonomic characterisation hampers the interpretation of these studies. Severe infectious diseases have also been associated with gastric lesions, probably due to interruption in feed intake and/or histamine release. Other agents, including fungi and parasites such as Hyostrongylus rubidus and Ascaris suum, have occasionally been associated with gastric lesions in pigs.

Evidence for a primate origin of zoonotic Helicobacter suis colonizing domesticated pigs

Helicobacter suis is the second most prevalent Helicobacter species in the stomach of humans suffering from gastric disease. This bacterium mainly inhabits the stomach of domesticated pigs, in which it causes gastric disease, but it appears to be absent in wild boars. Interestingly, it also colonizes the stomach of asymptomatic rhesus and cynomolgus monkeys. The origin of modern human-, pig- or non-human primate-associated H. suis strains in these respective host populations was hitherto unknown. Here we show that H. suis in pigs possibly originates from non-human primates. Our data suggest that a host jump from macaques to pigs happened between 100 000 and 15 000 years ago and that pig domestication has had a significant impact on the spread of H. suis in the pig population, from where this pathogen occasionally infects humans. Thus, in contrast to our expectations, H. suis appears to have evolved in its main host in a completely different way than its close relative Helicobacter pylori in humans.

Helicobacteriose em leitões: imuno-histoquímica em amostras colhidas por meio de gastroscopia

O diagnóstico da úlcera gastroesofágica (UGE) é fundamental para que se tente a recuperação dos afetados, entretanto há grande dificuldade na sua realização de forma precisa. Modernos endoscópios são ferramentas importantes nesse sentido e podem ser usados para determinar em que fase da criação a ulceração ocorre. A bactéria Helicobactertem sido associada à UGE e gerado perdas econômicas. Tendo em vista que poucos trabalhos têm sido realizados para identificação do problema precocemente, este estudo teve como objetivo detectar as lesões relacionando-as, ou não, com a bactéria Helicobacterspp., mediante análises macroscópica e histopatológica de amostras colhidas por meio da gastroscopia. Foram utilizados 20 animais de ambos os sexos, pesando entre 22 e 26kg e com 65 dias de idade. O aparelho utilizado foi um gastrovideoscópio da marca Karl Storz, modelo 1380NKS. Foram colhidas amostras das regiões anatômicas aglandular (quadrilátero esofágico) e glandular (cárdica, fúndica e pilórica) para o teste ultrarrápido da urease e para as avaliações histopatológicas e imuno-histoquímicas. Onze animais apresentaram lesões na região aglandular à endoscopia, e microscopicamente 15 animais apresentaram paraqueratose. Em 18 animais, foram observadas alterações em pelo menos uma das três regiões glandulares. As lesões foram maiores na região cárdica, seguida da antral e da fúndica. Em relação ao teste ultrarrápido da urease, sete animais foram negativos nas quatro regiões, e 13 positivos em pelo menos uma delas. Em relação à imuno-histoquímica (IHQ), 10 animais foram negativos em todas as regiões e 10 foram positivos em pelo menos uma delas. Os achados pré-ulcerativos não demonstraram relação com o Helicobacterspp., que apresenta caráter saprofítico e oportunista confirmado pela sua imunomarcação em áreas sem lesão.

An experimental Helicobacter suis infection causes gastritis and reduced daily weight gain in pigs

Helicobacter suis is a zoonotically important bacterium, that has been associated with gastritis and ulcerative lesions of the pars oesophagea of the stomach in pigs. Its exact role in these pathologies, however, still remains controversial. Therefore, a total of 29 medicated early weaned piglets were inoculated intragastrically or orally, with a total of 2 × 10(9) viable H. suis bacteria and the effect on gastric pathology and weight gain was determined. Twenty-three medicated early weaned piglets were inoculated with a sterile culture medium and used as sham-inoculated controls. The animals were euthanized between 28 and 42 days after inoculation. Infected animals showed a more severe gastritis compared to the control group. There was also a significant reduction of approximately 60 g per day (10%) in weight gain in H. suis inoculated animals compared to the sham-inoculated control animals. In conclusion, this study demonstrates for the first time that a pure in vitro culture of H. suis not only causes gastritis but also a marked decrease of the daily weight gain in experimentally infected pigs.

Detection of Helicobacter spp. in gastric, fecal and saliva samples from swine affected by gastric ulceration

The aim of this study was to evaluate the presence of Helicobacter (H.) spp. in swine affected by gastric ulceration. Stomachs from 400 regularly slaughtered swine were subjected to gross pathological examination to evaluate the presence of gastric ulcers. Sixty-five samples collected from ulcerated pars esophagea and 15 samples from non-ulcerated pyloric portions were submitted to histopathological and molecular analyses, to detect Helicobacter spp., H. suis and H. pylori by PCR. Feces and saliva swabs were also collected from 25 animals in order to detect in vivo the presence of Helicobacter spp.. Gastric ulcers were detected in 373 cases (93%). The presence of ulcers in association with inflammatory processes was further confirmed by histological examination. Forty-nine percent (32/65) of the ulcerated esophageal portions as well as 53% (8/15) of the non-ulcerated pyloric portions were positive for Helicobacter spp. by PCR. The Helicobacter spp. positive samples were also positive for H. suis, while H. pylori was not detected. These results were confirmed by restriction enzyme analysis. With regard to feces and saliva samples, 15/25 (60%) and 16/25 (64%) were positive for Helicobacter spp. PCR, respectively but all were negative in H. suis and H. pylori specific PCR.

Gastric helicobacters in domestic animals and nonhuman primates and their significance for human health

Helicobacters other than Helicobacter pylori have been associated with gastritis, gastric ulcers, and gastric mucosa-associated lymphoid tissue lymphoma in humans. These very fastidious microorganisms with a typical large spiral-shaped morphology were provisionally designated "H. heilmannii," but in fact they comprise at least five different Helicobacter species, all of which are known to colonize the gastric mucosa of animals. H. suis, which has been isolated from the stomachs of pigs, is the most prevalent gastric non-H. pylori Helicobacter species in humans. Other gastric non-H. pylori helicobacters colonizing the human stomach are H. felis, H. salomonis, H. bizzozeronii, and the still-uncultivable "Candidatus Helicobacter heilmannii." These microorganisms are often detected in the stomachs of dogs and cats. "Candidatus Helicobacter bovis" is highly prevalent in the abomasums of cattle but has only occasionally been detected in the stomachs of humans. There are clear indications that gastric non-H. pylori Helicobacter infections in humans originate from animals, and it is likely that transmission to humans occurs through direct contact. Little is known about the virulence factors of these microorganisms. The recent successes with in vitro isolation of non-H. pylori helicobacters from domestic animals open new perspectives for studying these microorganisms and their interactions with the host.

Alterações histológicas da pars esophagea de suínos e sua relação com Helicobacter spp

A relação entre Helicobacter spp. e a presença de alterações histológicas na pars esophagea de suínos foi avaliada em 67 estômagos de animais em idade de abate. Para a identificação das helicobactérias, utilizou-se a técnica da PCR com primers específicos para o gênero Helicobacter. As alterações histológicas foram identificadas e classificadas como ulceração, erosão, degeneração epitelial, alongamento de papilas, hiperplasia, paraqueratose, intensidade do infiltrado inflamatório e aumento do número de folículos linfoides. As alterações mais frequentemente encontradas na pars esophagea foram a degeneração epitelial e o alongamento de papilas, observadas em 83,5% (n=56) das amostras analisadas. Em 77,5% (n=52) das amostras, observou-se paraqueratose e em 61,1% (n=41) hiperplasia epitelial. Quarenta e sete (70,1%) foram positivas na PCR para Helicobacter spp. Nessas amostras a erosão foi a lesão mais observada (40,2%), seguida de ulceração da mucosa (11,9%). Em 58,2% das amostras positivas na PCR, não foram observadas ulcerações de mucosa. Observou-se associação significativa (P=0,003) entre a presença de Helicobacter spp. e a degeneração epitelial da pars esophagea de suínos em idade de abate.

Non-Helicobacter pylori helicobacters detected in the stomach of humans comprise several naturally occurring Helicobacter species in animals

Besides the well-known gastric pathogen Helicobacter pylori, other Helicobacter species with a spiral morphology have been detected in a minority of human patients who have undergone gastroscopy. The very fastidious nature of these non-Helicobacter pylori helicobacters (NHPH) makes their in vitro isolation difficult. These organisms have been designated 'Helicobacter heilmannii'. However, sequencing of several genes detected in NHPH-infected tissues has shown that the 'H. heilmannii' group comprises at least five different Helicobacter species, all of them known to colonize the stomach of animals. Recent investigations have indicated that Helicobacter suis is the most prevalent NHPH species in human. This species has only recently been isolated in vitro from porcine stomach mucosa. Other NHPH that colonize the human stomach are Helicobacter felis, Helicobacter bizzozeronii, Helicobacter salomonis and 'Candidatus Helicobacter heilmannii'. In numerous case reports of human gastric NHPH infections, no substantial information is available about the species status of the infecting strain, making it difficult to link the species with certain pathologies. This review aims to clarify the complex nomenclature of NHPH species associated with human gastric disease and their possible animal origin. It is proposed to use the term 'gastric NHPH' to designate gastric spirals that are morphologically different from H. pylori when no identification is available at the species level. Species designations should be reserved for those situations in which the species is defined.

Gastric zygomycosis in a pig affected with postweaning multisystemic wasting syndrome--case report

A postweaning pig died in spite of antibiotic therapy showing wasting in a small herd. Postweaning multisystemic wasting syndrome (PMWS) was diagnosed on the basis of gross pathological and histological lesions and the presence of moderate amounts of porcine circovirus 2 (PCV2) antigen in tissue samples. Mycotic gastritis caused by Zygomycetes spp. was found on round areas with a diameter of 1 to 3 cm in the glandular mucosa of the stomach. Moderate amount of PCV2 viral antigen was detected almost evenly in the stomach and mostly in the macrophages. In addition, acute uraemia, revealed by an ammonia-like stink of the gastric mucosa and the presence of acute erosions on the glandular mucosa of the stomach, was observed as a consequence of PCV2-induced interstitial nephritis. Only PCV2 infection could be identified as a cause of secondary mycotic gastritis. The results further support the immunosuppressive ability of PCV2 infection in PMWS-affected pigs.

Cell proliferation in pathogenesis of esophagogastric lesions in pigs

Esophagogastric ulcer is an independent disease in swine that is characterized by ulcerous autodigestion of the cutaneous mucosa, which does not exhibit a tendency to recover, but, on the contrary, a tendency toward severe hemorrhaging, with a predominantly lethal outcome. Since it develops in the part of the stomach that is morphologically and functionally different from other glandular mucosa, it was questioned earlier whether it could be a peptic ulcer based on its nature. Spontaneous ulcers, usually of the stomach, commonly occur in many domestic animals. Some of these lesions are chronic and they may occur in either the glandular or squamous-lined regions of the stomach. As with the human disease, the pathogenesis in domestic animals is multifactorial, poorly understood, and variable between and within species. Environmental stress and dietary factors are very important in the ulcer disease in swine. It has been shown that the Helicobacter spp. is strongly associated with naturally occurring ulcer and preulcer lesions of the pars esophagea in swine, which raises the possibility that Helicobacter spp. is an important factor in the pathogenesis of these lesions. The dynamics of the development of esophagogastric ulcers imply hyperplastic lesions (parakeratosis and hyperkeratosis), keratolysis, erosions, peptic necrosis, and the development of ulcers with all the characteristics of peptic ulcerations in other localities. In addition, K6 is expressed in association with the mucosal changes. The pattern of the intermediate filaments of keratin suggests that epithelial proliferation, which leads to visible hyperkeratosis, constitutes the essence of gastric ulcers in swine.

Detection of helicobacter candidatus suis by PCR in oesophagogastric ulcers of swine in Italy

The aim of this study was to evaluate by PCR the presence of Helicobacter spp. in gastric mucus from the fundic region of the stomach and to investigate its role in oesophagogastric ulcers in swine bred and regularly slaughtered in Piedmont (Northern Italy). Stomachs from 595 regularly slaughtered swine were subjected to gross pathological examination in order to evaluate the presence of gastric ulcers (revealed in 75 cases, 12.6%). Histopathological examination was performed to better characterise erosions and ulcers. DNA extracted from gastric mucus collected from all the ulcer-affected and from 25 normal stomachs was submitted to PCR using Helicobacter spp. 16S rRNA gene target primers. Sixty-three percent (47/75) of the affected stomachs was positive as well as 24% (6/25) of the non-affected ones. Sequence analysis from 5 positive samples showed 99% homology with Helicobacter candidatus suis 16S ribosomal RNA gene.

Age-dependent seroprevalence of antibodies against aHelicobacter pylori–like organism andHelicobacter pyloriin commercially reared swine

OBJECTIVE

To determine the prevalence of antibodies against a swine-origin Helicobacter pylori-like organism (HPLO) and H pylori in conventionally reared swine.

ANIMALS

640 conventionally reared swine of various ages from 16 high-health farms in Canada, 20 sows from Ohio, and 35 gnotobiotic swine.

PROCEDURES

Blood was collected from the cranial vena cava. Sera were collected and tested via ELISA for antibodies against antigen prepared from a swine-origin HPLO and human H pylori strain 26695.

RESULTS

Antibodies reactive with a swine HPLO, H pylori, or both were detected in 483 of 640 swine from all 16 farms in western Canada. Seroprevalence varied with age and was low (5.6%) in suckling (<or= 4-week-old) swine and increasingly high in swine ranging from > 4 weeks old to adulthood.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggested that colonization by a swine-origin HPLO, H pylori, or both and resultant seroconversion, like that of H pylori infection in humans, were common in commercial swine operations. Furthermore, data indicated that gastric infection was acquired at an early age. The relationships to gastric colonization by HPLOs and clinical manifestations of disease such as gastritis and gastroesophageal ulceration remain to be determined.