Detection of Helicobacter-like DNA in the gastric mucosa of Thoroughbred horses

Field study examining the mucosal microbiome in equine glandular gastric disease

Equine glandular gastric disease (EGGD) is a common disease among athletic horses that can negatively impact health and performance. The pathophysiology of this EGGD remains poorly understood. Previous studies using controlled populations of horses identified differences in the gastric glandular mucosal microbiome associated with disease. The objective of this study was to compare the gastric microbiome in horses with EGGD and those without across multiple barns and differing management practices. We hypothesized that alterations in the microbiome of the gastric glandular mucosa are associated with EGGD. A secondary objective was to perform a risk factor analysis for EGGD using the diet and management data collected. Microbial populations of biopsies from normal pyloric mucosa of horses without EGGD (control biopsies), normal pyloric mucosa of horses with EGGD (normal biopsies) and areas of glandular mucosal disruption in horses with EGGD (lesion biopsies) were compared. Lesion biopsies had a different microbial community structure than control biopsies. Control biopsies had a higher read count for the phylum Actinomycetota compared to lesion biopsies. Control biopsies also had an enrichment of the genera Staphylococcus and Lawsonella and the species Streptococcus salivarius. Lesion biopsies had an enrichment of the genera Lactobacillus and Actinobacillus and the species Lactobacillus equigenerosi. These results demonstrate differences in the gastric glandular microbiome between sites of disrupted mucosa in horses with EGGD compared to pyloric mucosa of horses without EGGD. Risk factor analysis indicated that exercise duration per week was a risk factor for EGGD.

Evaluation of a Comprehensive Profile of Salivary Analytes for the Diagnosis of the Equine Gastric Ulcer Syndrome

In this report, the measurement of salivary biomarkers as an aid for diagnosis of equine gastric ulcer syndrome (EGUS) was studied. A comprehensive panel of 23 salivary analytes was measured in the saliva of horses affected by EGUS and compared to healthy animals and horses with other diseases clinically similar to EGUS but with a negative diagnosis at gastroscopic examination. A total of 147 horses were included in the study and divided into heathy population (n = 12), the EGUS group (n = 110), and the group of horses with other diseases (n = 25). From the 23 analytes studied, 17 showed increased values in EGUS horses when compared to healthy ones, and uric acid, triglycerides, and calcium were significantly increased in horses with EGUS compared to the group of other diseases. The receiver operating characteristic curve analyses showed a modest but significant discriminatory power of those three analytes to identify EGUS from other diseases with similar symptoms. The discriminatory power enhanced when the results of the three analytes were combined. In conclusion, the results showed that selected salivary analytes could have potential use as biomarkers in horses with EGUS.

Determinación de Helicobacter spp. en mucosa gástrica glandular de mulas a través de la prueba de la actividad de la ureasa e histopatología

La información sobre la presentación y los factores predisponentes del síndrome de úlcera gástrica en mulas (SUGM) es escasa en comparación con el síndrome de úlcera gástrica en equinos (SUGE) y asnales. Debido a la naturaleza multifactorial de este síndrome, la helicobacteriosis ha sido estudiada en otras especies. El objetivo fue establecer la presencia de Helicobacter spp. en mucosa gástrica de mulas a través de la prueba rápida de la ureasa (PRU) y de análisis histopatológico. Menos del 27% de las muestras reaccionaron a la PRU, con tiempos prolongados de reacción, y al Agar Urea (prueba de oro), con menor porcentaje de positividad. La histopatología reveló procesos inflamatorios crónicos, sin presencia de bacterias curvoespiraladas. Las PRU no fueron conclusivas en la determinación de Helicobacter spp., comportamiento similar reportado en equinos. Se requieren exámenes diagnósticos específicos y procedimientos complementarios que explore regiones del estómago en consideración del número de muestras representativas.

A study comparing the healthy and diseased equine glandular gastric microbiota sampled with sheathed transendoscopic cytology brushes

BACKGROUND

The role of the equine gastrointestinal microbiota in the pathogenesis of equine glandular gastric disease (EGGD) is poorly understood.

OBJECTIVES

To investigate whether the glandular gastric microbiota is altered in horses with EGGD.

STUDY DESIGN

Prospective longitudinal study METHODS: Five Thoroughbred racehorses from one training centre underwent gastroscopy as part of poor performance investigation. Samples were taken from EGGD lesions and adjacent normal mucosa using sheathed transendoscopic cytology brushes and frozen at -80 °C. DNA was extracted for 16S rRNA sequencing, and sequences compared against a database to generate taxonomic classification of the microbiota. The same horses were sampled six months later.

RESULTS

Normal glandular mucosal samples were characterised by a higher proportion of Proteobacteria (46.3 %) than EGGD lesions (18.9 %). Relative abundance of Firmicutes was lower in samples from normal mucosa (20.0 %) than EGGD lesions (41.2 %). Linear discriminant analysis effect size (LEfSe) confirmed a greater proportion of Firmicutes species was characteristic of samples collected from EGGD lesions due to a very high relative abundance of Sarcina (up to 92.4 %) in two horses with EGGD. We were unable to comment on the stability of the glandular gastric microbiota over time.

MAIN LIMITATIONS

Small sample population. None of the horses examined had grossly normal gastric mucosa.

CONCLUSIONS

The gastric microbiota appears altered in EGGD, although we are unable to demonstrate a causative effect. Sarcina was particularly increased in abundance in EGGD and may be a useful biomarker of disease. Sheathed cytology brushes were an effective method for sampling the gastric mucosa.

Occurrence of Helicobacter spp. and Fecal Bacterial Contamination in High-altitude Aquatic Environments from the Andes

The occurrence of Helicobacter spp. and fecal bacterial contamination was investigated in high-altitude environments from the Northeastern Andes of Venezuela. Helicobacter DNA was detected by PCR in streams, drinking and irrigation waters, and one culture from drinking water by the HP enrichment medium for selection of Helicobacter pylori, which displayed 98.98% homology to this pathogen based on 16S rRNA gene sequencing. FISH demonstrated predominant coccoid cells of the target bacteria indicative of the viable but nonculturable (VBNC) state in all water samples and HP cultures. Our work reveals for the first time Helicobacter spp. in waters from one of the highest places in the world. These results, together with the presence of fecal coliforms (2-160 MPN/100 mL) from the headwaters of rivers to drinking and irrigation waters, alert fecal contamination and epidemiological implications in this area of ecological and economic importance for the region.

Gastric microbiome in horses with and without equine glandular gastric disease

Background

The role of the gastric microbiome in development or persistence of equine glandular gastric disease (EGGD) remains to be investigated.

Hypothesis/Objectives

The objective was to characterize the glandular mucosal and gastric fluid microbiomes of horses with and without EGGD. It was hypothesized that differences in the mucosal microbiome are associated with EGGD.

Animals

Twenty‐four horses were enrolled.

Methods

Gastroscopy was performed and EGGD scores recorded (score 0, n = 6; score 1, n = 8; score ≥2, n = 10). Gastric fluid and pinch biopsies of healthy glandular mucosa and EGGD lesions were collected via gastroscope. 16S rRNA amplicon sequencing of the gastric fluid and glandular mucosal biopsies was performed. Relationships between gastric fluid and mucosal microbial community composition were evaluated among EGGD score groups (EGGD 0‐BX, EGGD 1‐BX, EGGD ≥2‐BX) and among endoscopic appearances: controls from horses without EGGD and normal areas, hyperemic areas, and lesions from horses with EGGD.

Results

Microbial community structure of mucosal biopsies differed among EGGD score groups (Jaccard similarity index; P = .009). Principal coordinate analysis showed separate clusters for EGGD 0‐BX and EGGD ≥2‐BX.

Conclusions and Clinical Importance

A modest difference was detected in the community structure of the gastric glandular mucosal microbiome in association with EGGD score.

The Safety, Tolerability and Efficacy of Probiotic Bacteria for Equine Use

Probiotic bacteria are used widely as nutritional supplements and treatment interventions in the management of livestock and companion animals. The aim of this review is to summarize the current evidence reporting on the safety, tolerability and efficacy of probiotic bacteria use in horses. An online search of five databases for studies reporting on the use of probiotic bacteria use in horses which were either healthy or had a gastrointestinal or extraintestinal disease was conducted. A total of 18 articles were eligible for full review. No clear benefits were identified to support supplementation of equids with probiotic bacteria to improve starch and fiber digestion, nor for the treatment of colic or prevention of salmonellosis. Conflicting results were seen with the management of scouring in neonatal foals. Exacerbation of diarrhea and additional adverse events were reported in response to the administration of high doses of novel probiotic bacterial species. Probiotic bacteria given to exercising horses, improved aerobic fitness and stamina. The majority of probiotic bacterial species used in equine studies are bacterial species commonly used for human consumption and indigenous to the human gastrointestinal microbiota. There is a paucity of evidence to support the use of probiotic bacteria in the health maintenance and disease management of horses. While there are unclear and conflicting results associated with probiotic bacteria use for gastrointestinal conditions in both horses and foals, the administration of multistrain bacterial formulations to increase stamina in exercising horses shows promise.

Effect of oral administration of omeprazole on the microbiota of the gastric glandular mucosa and feces of healthy horses

BACKGROUND

Omeprazole administration is associated with changes in gastric and fecal microbiota and increased incidence of Clostridioides difficile enterocolitis in humans and dogs.

HYPOTHESIS/OBJECTIVES

Study purpose was to assess the effect of omeprazole on gastric glandular and fecal microbiota in healthy adult horses.

ANIMALS

Eight healthy horses stabled on straw and fed 100% haylage.

METHODS

Prospective controlled study. Transendoscopic gastric glandular biopsies, gastric fluid, and fecal samples were obtained from each horse twice at a 7-day interval before the administration of omeprazole. Samples were taken on the same horses before and after a 7-day administration of omeprazole (4 mg/kg PO q24h). pH was assessed on fresh gastric fluid and other samples were kept at -20°C until analysis. Bacterial taxonomy profiling was obtained by V1V3 16S amplicon sequencing from feces and gastric glandular biopsies. Analysis of alpha, beta diversity, and comparison between time points were performed with MOTHUR and results were considered significant when P < .05.

RESULTS

Gastric pH increased significantly after 7 days of omeprazole administration (P = .006). Omeprazole did not induce significant major changes in composition of fecal or gastric glandular microbiota, however, after administration, certain microbial genera became more predominant in the gastric glandular mucosa (lower Simpson's evenness, P = .05). Only the genus Clostridium sensu strictu_1 had a significant shift in the glandular gastric mucosa after omeprazole administration (P = .002). No population shifts were observed in feces.

CONCLUSIONS AND CLINICAL IMPORTANCE

Oral administration of omeprazole could have fewer effects in gastrointestinal microbiota in the horse compared to other species.

Equine glandular gastric disease: prevalence, impact and management strategies

Equine glandular gastric disease (EGGD) is an increasingly recognized disease of the glandular mucosa of the equine stomach. Diagnosis is confirmed by gastric endoscopy and scored based upon one of several different endoscopic scoring systems. Prevalence appears to be variable, depending upon breed and discipline. Primary identified risk factors include exercise frequency, and stress; therefore, management strategies are focused on reducing exercise and stress. Limiting grain intake and increasing pasture turnout may also be helpful preventative measures. Pharmacologic treatment consists primarily of an approved omeprazole product with or without misoprostol or sucralfate. Further research into the pathophysiology of EGGD may allow for identification of other targeted treatments.

Oral and Cloacal Helicobacter Detection in Wild and Captive Orinoco Crocodiles (Crocodylus intermedius) in Venezuela

Helicobacter species can colonize digestive tract of animals and humans and have been associated with gastrointestinal diseases; however, this genus has not been studied in crocodiles. Our objective was to detect by PCR Helicobacter genus and Helicobacter pylori in oral and cloacal swabs from Orinoco crocodiles of two wild (Cojedes River System and Capanaparo River) and two captive breeding centers (CBCs; Masaguaral Ranch and UNELLEZ) populations. Bacterial DNA was found in 100% of oral samples (10 wild and 10 captives), and in the 95% of cloacal samples (10 wild and 9 captives). In wild populations, Helicobacter spp. was not detected, whereas in CBCs, Helicobacter was detected in 10% of the oral samples, and 66.7% of cloacal samples. H. pylori was detected in two Orinoco crocodiles. Two cloacal non-pylori Helicobacter amplicons were sequenced, showing low similarity (≤97%) to Helicobacter sequences reported. This is the first report of Helicobacter species, including H. pylori in Crocodylus intermedius from CBCs.

Helicobacter pylori-induced gastric pathology: insights from in vivo and ex vivo models

Gastric colonization with Helicobacter pylori induces diverse human pathological conditions, including superficial gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma and its precursors. The treatment of these conditions often relies on the eradication of H. pylori, an intervention that is increasingly difficult to achieve and that does not prevent disease progression in some contexts. There is, therefore, a pressing need to develop new experimental models of H. pylori-associated gastric pathology to support novel drug development in this field. Here, we review the current status of in vivo and ex vivo models of gastric H. pylori colonization, and of Helicobacter-induced gastric pathology, focusing on models of gastric pathology induced by H. pylori, Helicobacter felis and Helicobacter suis in rodents and large animals. We also discuss the more recent development of gastric organoid cultures from murine and human gastric tissue, as well as from human pluripotent stem cells, and the outcomes of H. pylori infection in these systems.

First demonstration of equid gammaherpesviruses within the gastric mucosal epithelium of horses

Horses commonly develop gastric mucosal ulcers, similar to humans, a condition known as equine gastric ulcer syndrome (EGUS) that can lead to poor performance and lost training time and care expenses. Unlike humans, however, an infectious bacterial cause of ulcers has not been conclusively identified. Herpesviruses, while well-established causative agents of diseases such as cold sores, genital lesions, and certain types of cancer, have also been implicated in the development of a subset of gastric ulcers in humans. The presence of equid herpesviruses in the gastrointestinal tract and their potential contribution to EGUS has not been evaluated. Here, we provide the first evidence of equid gammaherpesviruses 2 and 5 (EHV-2 and -5) within the epithelium of the gastric mucosa of horses. These viruses were initially detected by a nested PCR screen of gastric tissue samples obtained from client- and university-owned horses with and without ulcers; however, no association with EGUS was found in this limited sample set. We then validated a highly sensitive in situ hybridization (ISH) assay and used this assay to characterize the distribution of these viruses in necropsy gastric tissue samples from five racehorses. Analyses revealed frequent EHV-2 and EHV-5 co-infections within the gastric mucosal epithelium, regardless of the ulcer status. These results are the first to demonstrate the presence of equid gammaherpesviruses in the gastric mucosa of horses and warrants further investigation to determine the contribution of these viruses to the development of EGUS and/or other gastrointestinal diseases.

Therapeutics for Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) is an umbrella term used to describe ulcers in the nonglandular squamous and glandular mucosa, terminal esophagus, and proximal duodenum. Gastric ulcers in the squamous and glandular regions occur more often than esophageal or duodenal ulcers and likely have a different pathogenesis. At present, omeprazole is accepted globally as the best pharmacologic therapy for both regions of the stomach; however, the addition of coating agents and synthetic prostaglandins could add to its effectiveness in treatment of EGUS. Dietary and environmental management are necessary for prevention of recurrence.

Low occurrence of Helicobacter DNA in tropical wild birds, Venezuela

Enteric Helicobacter species (Helicobacter pullorum, Helicobacter pametensis, Helicobacter canadensis, Helicobacter anseris, and Helicobacter brantae) have been found in birds from temperate latitudes. We evaluated the occurrence of Helicobacter spp. in terrestrial wild birds from Venezuela. A fragment of 16S rRNA gene was amplified by PCR with Helicobacter genus-specific primers. Helicobacter spp. were detected in four of 80 fecal and in three of 42 intestinal tissue samples. Analyses of 16S and 23S rRNA gene sequences confirm for the first time the presence of Helicobacter in tropical terrestrial wild birds. However, the occurrence of Helicobacter was low, suggesting these bacteria may be uncommon in the populations we studied.

Administration of trimethoprim-sulphadimidine does not improve healing of glandular gastric ulceration in horses receiving omeprazole: a randomised, blinded, clinical study

Background

Interest in Equine Gastric Ulcer Syndrome (EGUS) has recently increased in part due to a growing awareness of the differences between squamous and glandular disease. The pathophysiology and epidemiology of squamous and glandular disease are different and recently it has been shown that the response of glandular gastric ulceration to monotherapy with omeprazole is poor. Given these differences it has been recommended that specific treatment guidelines be formulated for equine glandular disease and that adjunctive therapies be investigated. Along these lines it has been suggested that the addition of antimicrobials may enhance healing. The objective of this study was to investigate whether the addition of trimethoprim-sulphadimidine to omeprazole therapy would result in superior healing of naturally occurring equine glandular ulceration compared with omeprazole monotherapy.

Results

Combination therapy of omeprazole plus trimethoprim-sulphadimidine could not be demonstrated to be superior to omeprazole monotherapy. Healing of the glandular mucosa was observed in 7/15 (47%; 95% CI 24 to 71%) and 3/13 (23%; 95% CI 7% to 50%) of horses in the TMPS and OMEP groups, respectively (OR?=?1.8; 95% CI 0.32 to 10.0; p?=?0.67). Improvement of the glandular mucosa was observed in 12/15 (80%; 95% CI 56 to 94%) and 9/13 (69%; 95% CI 42 to 89%) of horses in the TMPS and OMEP groups, respectively (OR?=?2.9; 95% CI 0.6 to 15.0; p?=?0.25).

Conclusions

The results of the present study do not support the addition of trimethoprim-sulphadimidine to therapeutic protocols for equine glandular ulceration. Several limitations were present in the study and the use of antimicrobials as an adjunctive treatment warrants further investigation. However, given the potential deleterious consequences associated with the indiscriminate use of antimicrobials, the inclusion of antimicrobials in treatment regimes for EGUS is not justified until their efficacy is further validated.

A comparison of three doses of omeprazole in the treatment of equine gastric ulcer syndrome: A blinded, randomised, dose-response clinical trial

REASONS FOR PERFORMING THE STUDY

A previous study demonstrated that a dose effect between 1.6 and 4.0 mg/kg bwt of omeprazole per os s.i.d. is present in the treatment of equine gastric ulceration. In the same study, healing of glandular ulceration appeared inferior to healing of squamous ulceration. However, several limitations were recognised in that study and further investigation is warranted.

OBJECTIVES

To further investigate the presence of a dose relationship in the treatment of gastric ulceration under conditions that may favour omeprazole efficacy such as administration prior to exercise and after a brief fast, and potential differences between the response of squamous and glandular ulceration to omeprazole therapy.

STUDY DESIGN

A blinded, randomised, dose-response clinical trial.

METHODS

Sixty Thoroughbred racehorses with grade ≥2/4 squamous and/or glandular ulceration were identified by gastroscopy. Horses were randomly assigned to receive either 1.0, 2.0 or 4.0 mg/kg bwt of enteric coated omeprazole per os s.i.d. 1-4 h prior to exercise. Gastroscopy was repeated at approximately 28 days.

RESULTS

The lower doses studied (1.0 and 2.0 mg/kg bwt) were noninferior to the reference dose (4.0 mg/kg bwt) in the treatment of squamous ulceration. Healing was greater in squamous ulceration than glandular ulceration (86% vs. 14%; P<0.0001). Improvement in ulcer grade was more likely in squamous lesions than glandular lesions (96% vs. 34%; P<0.0001). Worsening of the glandular ulcer grade was observed in 36% of horses.

CONCLUSIONS

The results of this study suggest that, under the conditions studied, where omeprazole is administered before exercise and following a brief fast, doses of omeprazole as low as 1 mg/kg bwt per os s.i.d. may be as effective as higher doses. The proportion of glandular ulceration that heals with 28 days of omeprazole therapy is less than that of squamous ulceration.

ImproWin® in the treatment of gastric ulceration of the squamous mucosa in trotting racehorses

BACKGROUND

Gastric ulceration is highly prevalent in horses, and there is a large commercial market for feed-additives and non-licenced products that claim effect for prevention and treatment of gastric ulceration. ImproWin® has been used as a feed additive in horses with anecdotal evidence that it may have some positive effects on gastric ulceration.The aim of this study was to investigate the effect of ImproWin® treatment on spontaneously occurring gastric ulcers of the squamous mucosa in Standardbred and Coldblooded trotting racehorses. The study was performed as a randomised, double-blinded, single centre study with stratified semi cross-over design with breed as stratification factors. The horses were clinically and endoscopically examined prior to start and after three weeks of treatment. The ulcerations were scored in accordance with Equine Gastric Ulcer Council (EGUC) recommendations on a 5 point scale and on a 10 cm Visual Analogue Scale (VAS). The patients were responder-classified after 3 weeks. Responders in need of ulcer treatment were randomly allocated to 2 or 4 weeks of additional treatment. Non-responders to placebo were crossed to ImproWin®.

RESULTS

The 5-point EGUC score and VAS recorded score was significantly reduced (P ≤ 0.01) in both groups after 3 weeks of treatment. From 3 weeks to the end of treatment the score was further significantly reduced in the ImproWin® group (P ≤ 0.05). At the end of treatment, 78% in the ImproWin® group and 54.8% in the placebo group were classified as responders. The difference was significant (P = 0.04).

CONCLUSIONS

ImproWin® may aid the healing process of ulcers of the gastric squamous mucosa of trotters.

High frequency of Helicobacter pylori in the esophageal mucosa of dyspeptic patients and its possible association with histopathological alterations

BACKGROUND

Helicobacter pylori gastric colonization is known to be high in symptomatic subjects. However, only a few reports on the presence of H. pylori in the esophageal mucosa have been published. The aim of this study was to assess the frequency of H. pylori in the esophagus of dyspeptic patients and its association with histopathology.

METHODS

The presence of H. pylori in the gastroesophageal mucosa was detected by fluorescence in situ hybridization (FISH) and PCR analysis of DNA extracted from gastric and esophageal biopsies of 82 symptomatic patients, using genus- and species-specific PCR primers. Alterations in the gastroesophageal mucosa were assessed by conventional histological techniques.

RESULTS

H. pylori in the stomach was detected by PCR and FISH, respectively, in 61% (n=43) and 90% (n=63) of dyspeptic patients, and in the esophagus in 70% (n=44) and 73% (n=46). The prevalence of cagA-positive strains by PCR varied from 50% (n=35) in the gastric mucosa to 65% (n=41) in the esophageal mucosa. By combining the results of both methods, H. pylori was present in the gastroesophageal mucosa in 86% (n=68) of patients. The association of the presence of bacteria, including H. pylori, in the esophageal mucosa with histopathological alterations was statistically significant between microabscesses and bacteria (r=0.656, p<0.0001) and PCR detection and pseudogoblet cells (r=0.25, p<0.047).

CONCLUSIONS

This is the first report of the occurrence of H. pylori in the esophageal mucosa from dyspeptic Venezuelan patients. These results demonstrate the high prevalence of H. pylori in the esophagus, and its presence was correlated with signs of inflammation.

Evaluation of the Helicobacteraceae in the oral cavity of dogs

OBJECTIVE

To determine the Helicobacter spp present in the oral cavity of dogs and the relationship of those organisms with gastric Helicobacter spp to better define the potential for dog-human and dog-dog transmission.

SAMPLE

Saliva and dental plaque from 28 dogs and gastric biopsy specimens from a subset of 8 dogs.

PROCEDURES

PCR-based screening for Helicobacter spp was conducted on samples obtained from the oral cavity of 28 dogs. Comparative analysis was conducted on Helicobacteraceae 16S rDNA clone libraries from the oral cavity and stomach of a subset of 8 dogs (5 vomiting and 3 healthy) that had positive PCR results for Helicobacter spp.

RESULTS

Helicobacteraceae DNA was identified in the oral cavity of 24 of 28 dogs. Analysis of cloned 16S rDNA amplicons from 8 dogs revealed that Wolinella spp was the most common (8/8 dogs) and abundant (52/57 [91%] clones) member of the Helicobacteraceae family in the oral cavity. Only 2 of 8 dogs harbored Helicobacter spp in the oral cavity, and 1 of those was coinfected with Helicobacter heilmannii and Helicobacter felis in samples obtained from the stomach and saliva. Evaluation of oral cavity DNA with Wolinella-specific PCR primers yielded positive results for 16 of 20 other dogs (24/28 samples were positive for Wolinella spp).

CONCLUSIONS AND CLINICAL RELEVANCE

Wolinella spp rather than Helicobacter spp were the predominant Helicobacteraceae in the oral cavity of dogs. The oral cavity of dogs was apparently not a zoonotically important reservoir of Helicobacter spp that were non-Helicobacter pylori organisms.

Equine stomachs harbor an abundant and diverse mucosal microbiota

Little is known about the gastric mucosal microbiota in healthy horses, and its role in gastric disease has not been critically examined. The present study used a combination of 16S rRNA bacterial tag-encoded pyrosequencing (bTEFAP) and fluorescence in situ hybridization (FISH) to characterize the composition and spatial distribution of selected gastric mucosal microbiota of healthy horses. Biopsy specimens of the squamous, glandular, antral, and any ulcerated mucosa were obtained from 6 healthy horses by gastroscopy and from 3 horses immediately postmortem. Pyrosequencing was performed on biopsy specimens from 6 of the horses and yielded 53,920 reads in total, with 631 to 4,345 reads in each region per horse. The microbiome segregated into two distinct clusters comprised of horses that were stabled, fed hay, and sampled at postmortem (cluster 1) and horses that were pastured on grass, fed hay, and biopsied gastroscopically after a 12-h fast (cluster 2). The types of bacteria obtained from different anatomic regions clustered by horse rather than region. The dominant bacteria in cluster 1 were Firmicutes (>83% reads/sample), mainly Streptococcus spp., Lactobacillus spp. and, Sarcina spp. Cluster 2 was more diverse, with predominantly Proteobacteria, Bacteroidetes, and Firmicutes, consisting of Actinobacillus spp. Moraxella spp., Prevotella spp., and Porphyromonas spp. Helicobacter sp. sequences were not identified in any of 53,920 reads. FISH (n = 9) revealed bacteria throughout the stomach in close apposition to the mucosa, with significantly more Streptococcus spp. present in the glandular region of the stomach. The equine stomach harbors an abundant and diverse mucosal microbiota that varies by individual.

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

Background

The equine glandular stomach is commonly affected by erosion and ulceration. The aim of this study was to assess whether bacteria, including Helicobacter, could be involved in the aetiology of gastric glandular lesions seen in horses.

Results

Stomach lesions, as well as normal appearing mucosa were obtained from horses slaughtered for human consumption. All samples were tested for urease activity using the Pyloritek^® assay, while mucosal bacterial content was evaluated using Fluorescence In Situ Hybridisation. In selected sub samples, bacteria characterisation was pursued further by cloning and sequencing. Mucosal lesions were found in 36/63 stomachs and included hyperplastic rugae, polypoid structures and focal erosions. None of the samples were tested positive for urease activity or for FISH using the Helicobacter genus specific probe. In samples of lesions, as well as normal samples, clones with 99% similarities to Lactobacillus salivarius and Sarcina ventriculi were found. Escherichia like bacterium clones and Enterococcus clones were demonstrated in one focal erosion. Based on a phylogenetic tree these clones had 100% similarity to Escherichia fergusonii and Enterococcus faecium. The Enterococcus were found colonising the mucosal surface, while E. fergusonii organisms were also demonstrated intraepithelial.

Conclusion

Gastric Helicobacter spp. could not be verified as being involved in lesions of the glandular stomach of the horse. Since E. fergusonii has been described as an emerging pathogen in both humans and animals, the finding of this bacterium in gastric erosion warrants further clarification to whether gastric infection with this type bacterium is important for horses.

Pathology of gastritis and gastric ulceration in the horse. Part 1: range of lesions present in 21 mature individuals

REASONS FOR PERFORMING STUDY

Gastric ulceration is now widely recognised as an important disease in high performance horses. Little is known about gastric histopathology in healthy or diseased animals; a comprehensive assessment would enhance interpretation of gross findings through assessment of their accuracy and allow for identification of lesion variety and pathogenesis in different anatomical regions of the stomach.

OBJECTIVES

To investigate the true extent and variety of gastric lesions in a mixed population of mature horses at post mortem.

METHODS

Stomachs were removed from a mixed population of 21 horses at post mortem. Mucosal abnormalities were recorded in photographic and written form. Representative samples from all gross lesions were taken for histopathology and processed routinely. Special stains including Gram, PAS and Warthin Starry, were used when appropriate. Pathological classification of lesion type using both gross and histological appearances was performed.

RESULTS

Classification of lesions within the squamous region included hyperkeratosis, punctate scars, diffuse erosions/ ulcerations and margo injuria; and within the glandular region, hyperaemia, focal erosions and ulcerations. Glandular metaplasia was recognised for the first time in the equine stomach. No Helicobacter-like organisms were detected in association with lesion development.

CONCLUSIONS AND POTENTIAL RELEVANCE

This study used gross and histological examination to highlight the large variety of naturally occurring gastric lesions in a mixed population of horses. Analysis of the pathogenesis of lesion development is now possible. Further research regarding the range of pathology in larger, more diverse groups of horses is required.

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.

Extragastric manifestations of Helicobacter pylori infection: other Helicobacters

The finding that Helicobacter pylori is the main cause of gastritis and peptic ulcer disease has opened a new era in the gastrointestinal world. Today there is evidence that H. pylori may also play a role in different nongastric diseases, opening the new "extragastric manifestations of H. pylori infection" field. Concerning this, several studies have been published in the last year. The most convincing data arise from those investigating idiopathic thrombocytopenic purpura and sideropenic anemia, while there is also an increasing evidence for a possible association with atherosclerotic disease. Furthermore, the discovery of a number of other novel Helicobacter species has stimulated the research in different extragastric diseases, in which an infectious hypothesis is plausible. In particular, several species have been studied for a potential role in different liver and intestinal diseases with interesting findings.

Specific and sensitive detection of H. pylori in biological specimens by real-time RT-PCR and in situ hybridization

PCR detection of H. pylori in biological specimens is rendered difficult by the extensive polymorphism of H. pylori genes and the suppressed expression of some genes in many strains. The goal of the present study was to (1) define a domain of the 16S rRNA sequence that is both highly conserved among H. pylori strains and also specific to the species, and (2) to develop and validate specific and sensitive molecular methods for the detection of H. pylori. We used a combination of in silico and molecular approaches to achieve sensitive and specific detection of H. pylori in biologic media. We sequenced two isolates from patients living in different continents and demonstrated that a 546-bp domain of the H. pylori 16S rRNA sequence was conserved in those strains and in published sequences. Within this conserved sequence, we defined a 229-bp domain that is 100% homologous in most H. pylori strains available in GenBank and also is specific for H. pylori. This sub-domain was then used to design (1) a set of high quality RT-PCR primers and probe that encompassed a 76-bp sequence and included at least two mismatches with other Helicobacter sp. 16S rRNA; and (2) in situ hybridization antisense probes. The sensitivity and specificity of the approaches were then demonstrated by using gastric biopsy specimens from patients and rhesus monkeys. This H. pylori-specific region of the 16S rRNA sequence is highly conserved among most H. pylori strains and allows specific detection, identification, and quantification of this bacterium in biological specimens.