Examination of equine glandular stomach lesions for bacteria, including Helicobacter spp by fluorescence in situ hybridisation.

This research focused on investigating the presence and impact of bacteria, specifically Helicobacter, on the development of stomach lesions in horses. However, the study concluded that Helicobacter spp. did not play a role in these lesions, but an emerging pathogen, Escherichia fergusonii, may warrant further study.

Study Details and Methods

• The researchers set out to examine instances of erosion and ulceration in the glandular stomachs of horses, common issues amongst this species. They particularly sought to discern whether bacteria, particularly of the Helicobacter genus, were involved in the development of these gastric issues.
• The study samples consisted of stomach lesions and normal-appearing mucosa from horses slaughtered for human consumption. These samples were then rigorously tested for bacterial presence.
• Two methods were used to evaluate the samples. The Pyloritek assay was used to test for urease activity, which is related to the presence of Helicobacter pylori. Fluorescence In Situ Hybridisation (FISH) was utilised to evaluate mucosal bacterial content.
• In specific subsamples, researchers went one step further by cloning and sequencing for further bacterial characterisation.

Results

• Out of 63 stomachs tested, lesions were found in 36. These included hyperplastic rugae, polypoid structures, and focal erosions. However, none of these samples tested positive for urease activity or for FISH using the Helicobacter genus specific probe, indicating that Helicobacter bacteria were not involved.
• Notably, samples from both healthy mucosa and lesion sites contained clones with high similarities to Lactobacillus salivarius and Sarcina ventriculi.
• In one focal erosion, clones that resembled Escherichia and Enterococcus were discovered. Further investigations confirmed their identity to be Escherichia fergusonii and Enterococcus faecium.
• The Enterococcus faecium was found on the mucosal surface while the E. fergusonii was also found within the epithelial layer.

Conclusions and Implications

• Contrary to the study’s initial premise, there was no verification of the involvement of Helicobacter spp. in the gastric lesions found in horse’s glandular stomachs. While Helicobacter was not involved, the discovery of E. fergusonii, an emerging pathogen in humans and animals, in the gastric erosion calls for further research.
• Through this study, it was concluded that the impact and role of E. fergusonii in horses, particularly with regards to gastric erosion, require additional exploration to fully understand its impact and potential treatment options.