Molecular detection of Helicobacter spp. and Fusobacterium gastrosuis in pigs and wild boars and its association with gastric histopathological alterations

Abstract

Besides Helicobacter pylori, a Gram-negative bacterium that may cause gastric disorders in humans, non-Helicobacter pylori helicobacters (NHPH) may also colonize the stomach of humans and animals. In pigs, H. suis can induce gastritis and may play a role in gastric ulcer disease, possibly in association with Fusobacterium gastrosuis. In the present study, gastric samples from 71 slaughtered pigs and 14 hunted free range wild boars were tested for the presence of DNA of F. gastrosuis and gastric Helicobacter species associated with pigs, dogs cats and humans, using species-specific PCR assays, followed by sequencing of the amplicon. These gastric samples were also histopathologically evaluated. Almost all the pigs presented gastritis (95.8%). Helicobacter spp. were detected in 78.9% and F. gastrosuis in 35.2% of the animals. H. suis was the most frequently identified Helicobacter species (57.7% of the animals), followed by a H. pylori-like species (50.7%) and less often H. salomonis and H. felis (each in 2.8% of the animals). H. suis was most often detected in the glandular (distal) part of the stomach (pars oesophagea 9.9%, oxyntic mucosa 35.2%, antral mucosa 40.8%), while the H. pylori-like species was mainly found in the non-glandular (proximal) part of the stomach (pars oesophagea 39.4%, oxyntic mucosa 14.1%, antral mucosa 4.2%). The great majority of wild boars were also affected with gastritis (71.4%) and Helicobacter spp. and F. gastrosuis were detected in 64.3% and 42.9% of the animals, respectively. H. bizzozeronii and H. salomonis were the most frequently detected Helicobacter species, while a H. pylori-like species and H. suis were only occasionally identified. These findings suggest that these microorganisms can colonize the stomach of both porcine species and may be associated with gastric pathology. This should, however, be confirmed through bacterial isolation. This is the first description of the presence of F. gastrosuis DNA in the stomach of wild boars and a H. pylori-like species in the pars oesophagea of the porcine stomach.

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

“…In this study, one biopsy sample of the fundic gland zone was positive in the ureAB-based H. pylorispeci c PCR assay, while negative in the glmM-based H. pylori-speci c PCR assay, indicating that this may concern the presence of H. pylori-like organisms, which is in accordance with the results obtained by Cortez Nunes et al [11]. Further evidence concerning the existence of these potentially novel gastric Helicobacter species and their possible signi cance for gastric disease in pigs should be obtained through isolation and genomic characterization of the organisms, ideally in a large multi-farm study.…”

“…Methods used for the detection of H. pylori-like organisms were based on previous work of Cortez Nunes et al [11]. This involved a H. pylori-speci c PCR assay based on the ureAB gene [11,13], followed by a H. pylori-speci c PCR assay based on the glmM gene [11,14] which was performed in samples positive in the former PCR assay and allowed to discriminate between H. pylori and H. pylori-like organisms. Since no reports have been made of pigs naturally infected with H. pylori, the latter assay (glmM-based) was expected to be negative.…”

“…Experimental infection in gnotobiotic piglets with an isolate of these H. pylorilike organisms, recovered from a conventionally reared piglet, has resulted in the development of gastritis and gastric ulceration [10]. Recently, Nunes Cortez et al reported the possible presence of H. pylori-like organisms in pigs, which were most frequently detected in the pars oesophagea, and their signi cant correlation with erosion [11]. However, these organisms have not yet been fully characterized and their signi cance remains to be explored.…”

Presence of potentially novel Helicobacter pylori-like organisms in gastric samples from cats and dogs

“…Of note, Krakowka et al [24] have reported the presence of H. pylori-like organisms in pigs, which are structurally and immunologically closely related to, however antigenically distinct from, H. pylori, and morphologically distinct from H. suis, which is a well-known pathogen in pigs. Such pig associated H. pylori-like organisms have also been described by Cortez Nunes et al [25] who detected Helicobacter species in DNA samples of gastric tissue of 36 out of 71 pigs (50.7%) for which ampli cation in a ureAB gene based H. pylori-speci c PCR assay was achieved (as con rmed by sequencing), but not in a glmM gene based H. pylori-speci c PCR assay.…”

“…6, photographs of the IHC stainings of biopsies 037DA and 043DC were chosen to represent the presence of H. pylori-like organisms since these demonstrated the morphology of H. pylori most clearly. In retrospect, the H. pylorispeci c ureAB sequences obtained from these biopsies showed highest similarity to a partial coding sequence deposited in the NCBI GenBank database described as 'Helicobacter pylori isolate 39 urease subunit A and urease subunit B genes' (accession number: MW714655.1), which was obtained from a stomach sample of a wild boar and the organism was later also de ned as a H. pylori-like organism based on PCR and sequencing analysis [25].…”