Investigating the causal relationship of gut microbiota with GERD and BE: a bidirectional mendelian randomization.

BACKGROUND: Gut microbiota(GM) have been proven associated with lots of gastrointestinal diseases, but its causal relationship with Gastroesophageal reflux disease(GERD) and Barrett's esophagus(BE) hasn't been explored. We aimed to uncover the causal relation between GM and GERD/BE and potential mediators by utilizing Mendelian Randomization(MR) analysis. METHODS: Summary statistics of GM(comprising 301 bacteria taxa and 205 metabolism pathways) were extracted from MiBioGen Consortium(N = 18,340) and Dutch Microbiome Project(N = 7,738), GERD and BE from a multitrait meta-analysis(NGERD=602,604, NBE=56,429). Bidirectional two-sample MR analysis and linkage disequilibrium score regression(LDSC) were used to explore the genetic correlation between GM and GERD/BE. Mediation MR analysis was performed for the risk factors of GERD/BE, including Body mass index(BMI), weight, type 2 diabetes, major depressive disorder(MDD), smoking initiation, alcohol consumption, and dietary intake(including carbohydrate, sugar, fat, protein intake), to detect the potential mediators between GM and GERD/BE. RESULTS: 11 bacterial taxa and 13 metabolism pathways were found associated with GERD, and 18 taxa and 5 pathways exhibited causal relationship with BE. Mediation MR analysis suggested weight and BMI played a crucial role in these relationships. LDSC identified 1 taxon and 4 metabolism pathways related to GERD, and 1 taxon related to BE. Specie Faecalibacterium prausnitzii had a suggestive impact on both GERD(OR = 1.087, 95%CI = 1.01-1.17) and BE(OR = 1.388, 95%CI = 1.03-1.86) and LDSC had determined their correlation. Reverse MR indicated that BE impacted 10 taxa and 4 pathways. CONCLUSIONS: This study established a causal link between gut microbiota and GERD/BE, and identified the probable mediators. It offers new insights into the role of gut microbiota in the development and progression of GERD and BE in the host.

Fusobacterium Detected in Barrett's Esophagus and Esophageal Adenocarcinoma Tissues.

We examined Fusobacterium nucreatum (F. nucleatum) and whole Fusobacterium species (Pan-fusobacterium) in non-neoplastic Barrett's esophagus (BE) from patients without cancer (n = 67; N group), with esophageal adenocarcinoma (EAC) (n = 27) and EAC tissue (n = 22). F. nucleatum was only detectable in 22.7% of EAC tissue. Pan-fusobacterium was enriched in EAC tissue and associated with aggressive clinicopathological features. Amount of Pan-fusobacterium in non-neoplastic BE was correlated with presence of hital hernia and telomere shortening. The result suggested potential association of Fusobacterium species in EAC and BE, featuring clinicpathological and molecular features.

Relationship between Helicobacter pylori Eradication and Barrett's Esophagus Elongation.

INTRODUCTION: Helicobacter pylori eradication therapy may worsen gastroesophageal reflux disease that is a significant risk factor for Barrett's esophagus. However, the relationship between eradication therapy and Barrett's esophagus remains controversial. This study evaluated the impact of Helicobacter pylori eradication on the lengthening of Barrett's esophagus. MATERIALS AND METHODS: We conducted a retrospective analysis of consecutive patients who successfully underwent Helicobacter pylori eradication between 2004 and 2017. Endoscopic images obtained before and after eradication therapy were compared for Barrett's esophagus length according to the Prague C&M criteria and the presence of reflux esophagitis based on the Los Angeles classification. RESULTS: A total of 340 patients were analyzed (mean age: 66.9 ± 12.9 years) for a median follow-up of 55 months (interquartile range: 29.8-89.3). At the initial endoscopic assessment, 187 patients (55%) had a hiatal hernia, and all patients had gastric atrophy (C-0 to I: 2%, C-II to III: 47%, O-I to III: 51%). Reflux esophagitis was detected in 7 patients (2%) before eradication and in 21 patients (6%) afterward, which was a significant increase (p = 0.007). Barrett's esophagus was identified in 69 patients (20%) before eradication, with a median length of C0M1. Elongation after treatment was observed in only 2 patients (0.6%). We observed no significant increase in either the prevalence (p = 0.85) or the median length (p = 0.5) of Barrett's esophagus. CONCLUSIONS: Only 0.6% of patients exhibited Barrett's esophagus lengthening after Helicobacter pylori eradication therapy, suggesting no significant impact of the treatment on the development or elongation of Barrett's esophagus.

A Meta-Analysis of the Impact of Obesity, Metabolic Syndrome, Insulin Resistance, and Microbiome on the Diagnosis of Barrett's Esophagus.

BACKGROUND AND AIM: The etiology and pathogenesis of Barrett's esophagus (BE) have been widely studied during recent decades. However, the association between BE and possible risk factors, including abdominal obesity (AO), metabolic syndrome (MetS), insulin resistance (IR), and the microbiome has not reached a consensus and lacks a systematic assessment. The purpose of our study is to evaluate, quantify, and summarize the association between these factors and BE risk. METHODS: A systematic search of Pubmed, Embase, and Cochrane Library databases was performed to identify relevant studies before September 2018. Studies were estimated with the OR, the weighted mean difference (WMD), and the 95% CI by using a random effects model. Subgroup analysis and publication bias were also performed. RESULTS: A total of 46 citations were included in the analysis, and 119,273 subjects were analyzed (AO 13, MetS 15, IR 9, and microbiome: 9). The pooled results showed that AO (p < 0.01, OR 1.30, 95% CI 1.11-1.52, I2 = 31.9%), MetS (p < 0.01, OR 1.68, 95% CI 1.40-2.01, I2 = 87.6%), and IR (p < 0.01, WMD 0.23, 95% CI 0.11-0.35, I2 = 55.8%) were all significantly associated with an increased risk of BE, but except for the microbiome (p > 0.05, OR 1.27, 95% CI 0.66-2.43, I2 = 46.7%). In addition, subgroup analyses were stratified by waist-to-hip ratio, waist circumference, body mass index, diagnosis criteria, strain type, geographical region, and study design, respectively. Moreover, we observed no evidence of publication bias in Egger's and Begg's tests. CONCLUSIONS: Our study reveals that AO, MetS, and IR are significantly associated with BE risk, except for the microbiome. The mechanism of BE induced by 3 risk factors should be further explored.

Novel Screening Tests for Barrett's Esophagus.

PURPOSE OF REVIEW: There has been an exponential increase in the incidence of esophageal adenocarcinoma (EAC) over the last half century. Barrett's esophagus (BE) is the only known precursor lesion of EAC. Screening for BE in high-risk populations has been advocated with the aim of identifying BE, followed by endoscopic surveillance to detect dysplasia and early stage cancer, with the intent that treatment can improve outcomes. We aimed to review BE screening methodologies currently recommended and in development. RECENT FINDINGS: Unsedated transnasal endoscopy allows for visualization of the distal esophagus, with potential for biopsy acquisition, and can be done in the office setting. Non-endoscopic screening methods being developed couple the use of swallowable esophageal cell sampling devices with BE specific biomarkers, as well as trefoil factor 3, methylated DNA markers, and microRNAs. This approach has promising accuracy. Circulating and exhaled volatile organic compounds and the foregut microbiome are also being explored as means of detecting EAC and BE in a non-invasive manner. Non-invasive diagnostic techniques have shown promise in the detection of BE and may be effective methods of screening high-risk patients.

Helicobacter pylori induces caudal-type homeobox protein 2 and cyclooxygenase 2 expression by modulating microRNAs in esophageal epithelial cells.

Dysregulation of microRNAs (miRNAs) has been linked to virulence factors of Helicobacter pylori. The role of H. pylori in esophageal disease has not been clearly defined. We previously reported that H. pylori esophageal colonization promotes the incidence of Barrett's esophagus and esophageal adenocarcinoma in vivo. Here, we studied the direct effects of H. pylori on the transformation of esophageal epithelial cells, with particular focus on whether H. pylori exerts its effects by modulating miRNAs and their downstream target genes. The normal human esophageal cell line HET-1A was chronically exposed to H. pylori extract and/or acidified deoxycholic acid for up to 36 weeks. The miRNA profiles of the esophageal epithelial cells associated with H. pylori infection were determined by microarray analysis. We found that chronic H. pylori exposure promoted acidified deoxycholic acid-induced morphological changes in HET-1A cells, along with aberrant overexpression of intestinal metaplasia markers and tumorigenic factors, including caudal-type homeobox protein 2 (CDX2), mucin 2, and cyclooxygenase 2 (COX2). Helicobacter pylori modified the miRNA profiles of esophageal epithelial cells, particularly aberrant silencing of miR-212-3p and miR-361-3p. Moreover, in biopsies from Barrett's esophagus patients, esophageal H. pylori colonization was associated with a significant decrease in miR-212-3p and miR-361-3p expression. Furthermore, we identified COX2 as a target of miR-212-3p, and CDX2 as a target of miR-361-3p. Helicobacter pylori infection of esophageal epithelial cells was associated with miRNA-mediated upregulation of oncoprotein CDX2 and COX2. Our observations provide new evidence about the molecular mechanisms underlying the association between H. pylori infection and esophageal carcinogenesis.

The Esophageal Microbiome in Health and Disease.

PURPOSE OF REVIEW: Investigation of the esophageal microbiome is a relatively new field. This review will outline data characterizing the esophageal microbiome in both health and disease states, including gastroesophageal reflux disease (GERD), Barrett's esophagus, esophageal cancer, eosinophilic esophagitis, and motility disorders. RECENT FINDINGS: While the esophagus was previously considered devoid of a significant bacterial population, development of culture-independent techniques, specifically 16S rRNA gene sequencing, as well as novel, minimally invasive microbial sampling modalities, has facilitated characterization of the esophageal microbiome in both health and several disease states. Although limited, there is evidence that the esophagus contains a diverse microbial population, with Gram-positive bacteria, specifically Streptococcus, dominating in health, while Gram-negative bacteria prevail in reflux disorders including GERD and Barrett's esophagus. The microbiome is altered with other esophageal disorders as well, including eosinophilic esophagitis and esophageal motility disorders, though these changes have been less well characterized. Characterization of the gut microbiome has advanced significantly; however, further investigation is essential. Understanding changes in the esophageal microbiome could affect our understanding of the natural history of diseases of the esophagus and present potential therapeutic approaches.

Helicobacter pylori and Barrett’s esophagus: a protective factor or a real cause?

Notwithstanding the definite aetiopathogenetic path of certain diseases, the relationship between Helicobacter pylori (H. pylori) and Barrett’s esophagus (BE), a condition that increases the risk for dysplasia and consequently adenocarcinoma of the distal esophagus and esophagogastric junction, remains uncertain. This paper reviews the current scientific literature with emphasis on the protective correlation between H. pylori infection and BE and demonstrates that a causal relationship has not been disproved with certainty. Furthermore, H. pylori infection could pose a risk for the onset of gastroesophageal reflux disease (GERD), which could in turn trigger BE, a precancerous lesion, and subsequently cause cancer. By analyzing the current available data, this article tries to verify that H. pylori infection is the underlying cause of esophageal cancer.

Associations of microbiota and toll-like receptor signaling pathway in esophageal adenocarcinoma.

BACKGROUND: Toll-like receptors (TLRs) recognize known molecules from microbes and have an established role in tumorigenesis. Using a rat model of esophageal adenocarcinoma, and human clinical samples, we investigated genes central to TLR-mediated signal transduction and characterized the esophageal microbiome across the spectrum of esophageal adenocarcinoma carcinogenesis. METHODS: We surgically induced bile/acid reflux in rats and their esophagi were harvested at 40 weeks post-surgery. Tissue samples from the model were selected for gene expression profiling. Additionally, for rat and human samples microbiome analysis was performed using PCR-ESI-MS-TOF technology with validation by fluorescence in situ hybridization. RESULTS: Gene expression results in the rat model indicated a significant upregulation of TLRs 1-3, 6, 7 and 9 in EAC compared to normal epithelium. PCR-ESI-MS-TOF analysis revealed a prevalence of Escherichia coli in Barrett's esophagus (60%) and esophageal adenocarcinoma (100%), which was validated by fluorescence in situ hybridization. In the human clinical samples, Streptococcus pneumonia was detected in high abundance in gastroesophageal reflux disease and Barrett's esophagus (50-70%) in comparison to tumor adjacent normal epithelium, dysplasia, and esophageal adenocarcinoma (20-30%). E. coli was detected in the Barrett's esophagus and esophageal adenocarcinoma groups but was absent in the tumor adjacent normal epithelium, dysplasia, and the gastroesophageal reflux disease groups. CONCLUSIONS: We demonstrated an association between the TLR signaling pathway and E. coli hinting towards possible early molecular changes being mediated by microbes in the rat model of esophageal adenocarcinoma carcinogenesis. Studies on human clinical samples also corroborate results to some extent; however, a study with larger sample size is needed to further explore this association.

Prevalence of upper gastrointestinal endoscopic findings in the community: A systematic review of studies in unselected samples of subjects.

BACKGROUND AND AIM: Upper gastrointestinal endoscopic findings, such as esophagitis, Barrett's esophagus, peptic ulcer, and malignancy, represent a public health problem. This systematic review aimed to evaluate the prevalence of upper gastrointestinal endoscopic findings in the community. METHODS: A systematic search was conducted in PUBMED and EMBASE to May 2015. Studies were eligible if they reported the prevalence of upper gastrointestinal endoscopic findings in unselected samples of the community. RESULTS: Twelve articles were eligible, nine reported data from three endoscopic surveys (n = 3063 subjects), and three from national screening programs (n = 84 153). The overall prevalence of upper gastrointestinal endoscopic findings in the community was 30% in the Kalixanda study (Sweden), 24.9% in the Loiano-Monghidoro study (Italy), and 68.9% in the Systematic Investigation of Gastrointestinal Diseases study (China). The pooled prevalence of esophagitis, endoscopically suspected esophageal metaplasia (ESEM), peptic ulcer, and gastric cancer in all studies was 11.2, 5.1, 6.8, and 0.33%, respectively. The most frequent finding was esophagitis in Europe, with a prevalence of 15.5% in Sweden and 11.8% in Italy, and peptic ulcer in China (17.1%), both in asymptomatic and symptomatic individuals. The prevalence of Helicobacter pylori was positively associated with the prevalence of peptic ulcer (r = 0.91) but negatively associated with the prevalence of both esophagitis (r = -0.99) and ESEM (r = -0.95). CONCLUSIONS: Upper gastrointestinal endoscopic findings are present in at least a quarter of subjects in the community with different patterns in Western and Eastern countries, both in asymptomatic and symptomatic subjects. H. pylori prevalence negatively impacts on the prevalence of reflux-related esophageal findings.

Potential Role of the Microbiome in Barrett's Esophagus and Esophageal Adenocarcinoma.

Esophageal adenocarcinoma and its precursor Barrett's esophagus have been rapidly increasing in incidence for half a century, for reasons not adequately explained by currently identified risk factors such as gastroesophageal reflux disease and obesity. The upper gastrointestinal microbiome may represent another potential cofactor. The distal esophagus has a distinct microbiome of predominantly oral-derived flora, which is altered in Barrett's esophagus and reflux esophagitis. Chronic low-grade inflammation or direct carcinogenesis from this altered microbiome may combine with known risk factors to promote Barrett's metaplasia and progression to adenocarcinoma.

Rebamipide Alters the Esophageal Microbiome and Reduces the Incidence of Barrett's Esophagus in a Rat Model.

BACKGROUND: Barrett's esophagus (BE) is characterized by a distinct Th2-predominant cytokine profile. However, antigens that shift the immune response toward the Th2 profile are unknown. AIM: We examined the effects of rebamipide on the esophageal microbiome and BE development in a rat model. METHODS: BE was induced by esophagojejunostomy in 8-week-old male Wistar rats. Rats were divided into control and rebamipide-treated group receiving either a normal or a 0.225 % rebamipide-containing diet, respectively, and killed 8, 16, 24, and 32 weeks after the operation. PCR-amplified 16S rDNAs extracted from esophageal samples were examined by terminal-restriction fragment length polymorphism (T-RFLP) analysis to assess microbiome composition. The dynamics of four bacterial genera (Lactobacillus, Clostridium, Streptococcus, and Enterococcus) were analyzed by real-time PCR. RESULTS: The incidences of BE in the control and rebamipide group at 24 and 32 weeks were 80 and 100, and 20 and 33 %, respectively. T-RFLP analysis of normal esophagus revealed that the proportion of Clostridium was 8.3 %, while that of Lactobacillales was 71.8 %. The proportions of Clostridium increased and that of Lactobacillales decreased at 8 weeks in both groups. Such changes were consistently observed in the control but not in the rebamipide group. Clostridium and Lactobacillus expression was lower and higher, respectively, in the rebamipide group than in the control group. CONCLUSIONS: Rebamipide reduced BE development and altered the esophageal microbiome composition, which might play a role in BE development.

Association between Helicobacter pylori and Barrett's esophagus, erosive esophagitis, and gastroesophageal reflux symptoms.

BACKGROUND & AIMS: Infection with Helicobacter pylori, particularly the cytotoxin-associated gene A (cagA)+ strain, is believed to protect against Barrett's esophagus, but it is not clear if it protects against gastroesophageal reflux disease (GERD). We aimed to determine whether H pylori infection is associated with GERD symptoms, erosive esophagitis, and Barrett's esophagus within the same cohort. METHODS: We analyzed data from a case-control study of 533 men (ages, 50-79 y) who underwent colorectal cancer screening at 2 tertiary medical centers in Michigan between 2008 and 2011 and who also were recruited to undergo upper endoscopy. We assessed 80 additional men found to have Barrett's esophagus during clinically indicated upper-endoscopy examinations. Logistic regression was used to estimate the associations between serum antibodies against H pylori or cagA and GERD symptoms, esophagitis, and Barrett's esophagus, compared with randomly selected men undergoing colorectal cancer screens (n = 177). RESULTS: H pylori infection was associated inversely with Barrett's esophagus (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.29-0.97), particularly the cagA+ strain (OR, 0.36; 95% CI, 0.14-0.90). There was a trend toward an inverse association with erosive esophagitis (H pylori OR, 0.63; 95% CI, 0.37-1.08; and cagA+ OR, 0.47; 95% CI, 0.21-1.03). However, GERD symptoms were not associated with H pylori infection (OR, 0.948; 95% CI, 0.548-1.64; and cagA+ OR, 0.967; 95% CI, 0.461-2.03). CONCLUSIONS: Based on a case-control study, infection with H pylori, particularly the cagA+ strain, is associated inversely with Barrett's esophagus. We observed a trend toward an inverse association with esophagitis, but not with GERD symptoms.

Gastric microbiota is altered in oesophagitis and Barrett's oesophagus and further modified by proton pump inhibitors.

Gastro-oesophageal reflux can cause inflammation, metaplasia, dysplasia and cancer of the oesophagus. Despite the increased use of proton pump inhibitors (PPIs) to treat reflux, the incidence of oesophageal adenocarcinoma has increased rapidly in Europe and in the United States in the last 25 years. The reasons for this increase remain unclear. In this study, we aimed to determine whether the microbiota of the gastric refluxate and oesophageal biopsies differs between patients with heartburn and normal-appearing oesophageal mucosa versus patients with abnormal oesophageal mucosa [oesophagitis or Barrett's oesophagus (BE)] and to elucidate the effect of PPIs on the bacterial communities using 16S rRNA gene pyrosequencing. Significant differences in the composition of gastric fluid bacteria were found between patients with heartburn and normal oesophageal tissue versus patients with oesophagitis or BE, but in the oesophagus-associated microbiota differences were relatively modest. Notably, increased levels of Enterobacteriaceae were observed in the gastric fluid of oesophagitis and BE patients. In addition, treatment with PPIs had dramatic effects on microbial communities both in the gastric fluids and the oesophageal tissue. In conclusion, gastric fluid microbiota is modified in patients with oesophagitis and BE compared with heartburn patients with normal biopsies. Furthermore, PPI treatment markedly alters gastric and oesophageal microbial populations. Determining whether the changes in bacterial composition caused by PPIs are beneficial or harmful will require further investigation.

Association between Helicobacter pylori and Barrett's esophagus: a case-control study.

OBJECTIVES: The estimated association between Helicobacter pylori and Barrett's esophagus (BE) has been heterogenous across previous studies. In this study, we aimed to examine the association between H. pylori and BE and to identify factors that may explain or modify this association. METHODS: We conducted a case-control study in which we used screening colonoscopy controls recruited from primary care clinics as our primary control group in order to minimize selection bias. All participants underwent an esophagogastroduodenoscopy with gastric mapping biopsies. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the association between H. pylori and BE while controlling for confounders. RESULTS: We identified 218 cases and 439 controls. The overall OR for the association between H. pylori and BE after controlling for age and white race was 0.55 (95% CI: 0.35-0.84). We observed an even stronger inverse association (OR: 0.28; 95% CI: 0.15, 0.50) among participants with corpus atrophy or antisecretory drug use ≥ 1 time per week (factors thought to lower gastric acidity), and no inverse association in patients without these factors (OR: 1.32; 95% CI: 0.66, 2.63). CONCLUSIONS: The association between H. pylori and a decreased risk for BE appears to occur in patients with factors that would likely lower gastric acidity (corpus atrophy or taking antisecretory drugs at least once a week).

Metagenomic analysis of the gastric microbiota cultivable from a patient with gastritis concomitant with Barrett's esophagus.

Barrett's esophagus is a distal metaplasia characterized by the transformation of squamous mucosa into columnar mucosa. This esophageal phenotype is a product not only of the chronic reflux of gastric acids, but also by microorganisms that colonize the oral cavity and stomach. Two classes of microbiota can be identified in Barrett's esophagus; microbiota type I is associated with the normal esophagus and type II with an inflamed esophagus. The present study describes the gastric microbiota of a patient with antral gastritis concomitant with Barrett's esophagus absent infection with Helicobacter pylori. Gastric biopsies were obtained following the protocol of Sydney and following ethical practices. The isolates were cultivated under microaerophilic conditions on Columbia Agar supplemented with IsoVitaleX™ and 7% sterile blood. Extracted DNA was sequenced using 454-GS and the results analyzed on the MG-RAST server. Gram negative isolates were found and bacteria resistant to levofloxacin, amoxicillin, tetracycline, erythromycin, and clarithromycin. The phyla Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria, the genus Bacteroides and the species group Bacteroides fragilis were most abundant. Functionally, the metabolism of carbohydrates, amino acids, and to a lesser extent, the metabolism of cofactors and vitamins were most dominant, and of which the enzymes ß-glucosidase (EC 3.2.1.21), ß-galactosidase (EC 3.2.1.23) and ß-N-acetylhexosaminidase (EC 3.2.1.52) were most dominant. The findings of this study, because they are of only one case may probably suggest a possible pathogenic role, previously undescribed for Bacteroides fragilis, associated with human gastritis when concomitant esophageal pathology exists.

Characterization of bacterial biota in the distal esophagus of Japanese patients with reflux esophagitis and Barrett's esophagus.

BACKGROUND: The distal esophagus harbors a complex bacterial population. We hypothesized that a better understanding of bacterial communities in the esophagus would facilitate understanding of the role of bacteria in esophageal disease. Here, we investigated bacterial composition in the distal esophagus in subjects with a normal esophagus, reflux esophagitis, and Barrett's esophagus. METHODS: Two biopsy specimens were obtained from the distal esophagus at 1 cm above the gastroesophageal junction under endoscopic examination in 18 patients (6 each with normal esophagus, reflux esophagitis, and Barrett's esophagus) and used for histological examination and DNA extraction. Fragments of 16S rDNA genes were amplified by PCR using general bacterial primers, and bacterial populations were examined. A third biopsy specimen was taken from the patients with Barrett's esophagus to histologically confirm the replacement of squamous epithelium with columnar epithelium in the distal esophagus. RESULTS: Endoscopic diagnoses of normal esophagus, esophagitis, and Barrett's esophagus were confirmed by histological findings. The total amount of bacterial DNA detected did not significantly differ among groups (p > 0.1). On average, each of the 18 subjects yielded about 350 clones, of which 40 were randomly picked and sequenced. Analysis of 147 16S rDNA sequences from 240 clones of 6 subjects with normal esophagus yielded four phyla, Proteobacteria (49%), Firmicutes (40%), Bacteroidetes (8%), and Actinobacteria (3%). Similar analysis of 139 16S rDNA sequences from 240 clones of 6 patients with reflux esophagitis yielded 6 phyla, Proteobacteria (43%), Firmicutes (33%), Bacteroidetes (10%), Fusobacteria (10%), Actinobacteria (2%), and TM7 (2%). while that of 138 16S rDNA sequences from 240 clones of 6 cases of Barrett's esophagus yielded 5 phyla, Firmicutes (55%), Proteobacteria (20%), Bacteroidetes (14%), Fusobacteria (9%), and Actinobacteria (2%). Thus, microbial communities differed among patients with a normal esophagus, reflux esophagitis and Barrett's esophagus. CONCLUSIONS: Esophageal bacterial composition differs under conditions of normal esophagus, reflux esophagitis, and Barrett's esophagus. Diverse bacterial communities may be associated with esophageal disease.

The prevalence of helicobacter pylori infection in patients with reflux esophagitis - our experience.

INTRODUCTION AND AIM: The role of Helicobacter pylori in esophageal disease has not been clearly defined. To clarify this issue, we analyzed 120 patients with histologically confirmed esophageal disease. MATERIAL AND METHODS: In this prospective study, 120 patients who underwent upper endoscopy examination were included; among them 70 patients with clinically, endoscopically and histologically confirmed GERD, and 50 patients with BE. This investigation was performed in the Clinic of Gastrohepatology in Prishtina, during the period: June 2009-December 2011. Each patient was investigated for H. pylori infection, by performing biopsy for HUT test. RESULTS: In BE group, H. pylori infection was present in 16.0% of patients. In GERD group, H. pylori infection was present in 42.9%, and in patients of the control group, in 52.0% of cases. So, in BE group, the prevalence of H. pylori infection showed less significant difference, compared to the control group (P = 0.003) and in GERD group (P = 0.0035). Between GERD group and the control group there was no significant difference (GERD vs. G control. P = 0.421). CONCLUSION: The prevalence of H. pylori infection in patients with BE (16%) was lower in comparison with patients with GERD (42.9%) and with control group (p <0.01). The prevalence of H. pylori infection in patients with BE, especially those with LSBE (9.1%) was very low, which indicates a possible protective role of this microorganism.

The association between Barrett's esophagus and Helicobacter pylori infection: a meta-analysis.

OBJECTIVE: The effect of Helicobacter pylori on Barrett's esophagus is poorly understood. We conducted a meta-analysis to summarize the existing literature examining the effect that H. pylori has on Barrett's esophagus. DESIGN: We performed a comprehensive search to identify studies pertaining to the association between H. pylori and Barrett's esophagus. We conducted meta-regression analyses to identify sources of variation in the effect of H. pylori on Barrett's esophagus. RESULTS: Our analysis included a total of 49 studies that examined the effect of H. pylori on Barrett's esophagus and seven studies that examined the effect of cag A positivity on Barrett's esophagus. Overall, H. pylori, and even more so cag A, tended to be protective for Barrett's esophagus in most studies; however, there was obvious heterogeneity across studies. The effect of H. pylori on Barrett's esophagus varied by geographic location and in the presence of selection and information biases. Only four studies were found without obvious selection and information bias, and these showed a protective effect of H. pylori on Barrett's esophagus (Relative risk = 0.46 [95% CI: 0.35, 0.60]). CONCLUSIONS: Estimates for the effect of H. pylori on Barrett's esophagus were heterogeneous across studies. We identified selection and information bias as potential sources of this heterogeneity. Few studies without obvious selection and information bias have been conducted to examine the effect of H. pylori on Barrett's esophagus, but in these, H. pylori infection is associated with a reduced risk of Barrett's esophagus.