The relationship between Porphyromonas gingivalis and oesophageal squamous cell carcinoma: a literature review.

Oesophageal cancer is the most common gastrointestinal malignancy in China and one of the major causes of death due to cancer worldwide. The occurrence of oesophageal cancer is a multifactor, multistage, and multistep process influenced by heredity, the environment, and microorganisms. Specifically, bacterial infection may be involved in the process of tissue carcinogenesis by directly or indirectly influencing tumour occurrence and development. Porphyromonas gingivalis is an important pathogen causing periodontitis, and periodontitis can promote the occurrence of various tumours. An increasing number of studies to date have shown that P. gingivalis plays an important role in the occurrence and development of oesophageal cancer. Overall, exploring how P. gingivalis promotes oesophageal cancer occurrence and development and how it affects the prognosis of these patients is of great importance for the diagnosis, prevention, and treatment of this type of cancer. Herein, the latest progress is reviewed.

Host-Microbiota Interactions in the Esophagus During Homeostasis and Allergic Inflammation.

BACKGROUND & AIMS: Microbiota composition and mechanisms of host-microbiota interactions in the esophagus are unclear. We aimed to uncover fundamental information about the esophageal microbiome and its potential significance to eosinophilic esophagitis (EoE). METHODS: Microbiota composition, transplantation potential, and antibiotic responsiveness in the esophagus were established via 16S ribosomal RNA sequencing. Functional outcomes of microbiota colonization were assessed by RNA sequencing analysis of mouse esophageal epithelium and compared with the human EoE transcriptome. The impact of dysbiosis was assessed using a preclinical model of EoE. RESULTS: We found that the murine esophagus is colonized with diverse microbial communities within the first month of life. The esophageal microbiota is distinct, dominated by Lactobacillales, and demonstrates spatial heterogeneity as the proximal and distal esophagus are enriched in Bifidobacteriales and Lactobacillales, respectively. Fecal matter transplantation restores the esophageal microbiota, demonstrating that the local environment drives diversity. Microbiota colonization modifies esophageal tissue morphology and gene expression that is enriched in pathways associated with epithelial barrier function and overlapping with genes involved in EoE, including POSTN, KLK5, and HIF1A. Finally, neonatal antibiotic treatment reduces the abundance of Lactobacillales and exaggerates type 2 inflammation in the esophagus. Clinical data substantiated loss of esophageal Lactobacillales in EoE compared with controls. CONCLUSIONS: The esophagus has a unique microbiome with notable differences between its proximal and distal regions. Fecal matter transplantation restores the esophageal microbiome. Antibiotic-induced dysbiosis exacerbates disease in a murine model of EoE. Collectively, these data establish the composition, transplantation potential, antibiotic responsiveness, and host-microbiota interaction in the esophagus and have implications for gastrointestinal health and disease.

Risk factors for the development of esophageal candidiasis among patients in community hospital.

The aim of this study was to clarify risk factors for esophageal candidiasis (EC) in immunocompetent patients in a community hospital. 7736 patients who underwent esophagogastroduodenoscopy at our hospital from April 2012 to July 2018 were enrolled. The relationships between EC and the following factors: age, gender, body mass index, lifestyle, lifestyle-related diseases, medication, and endoscopic findings were analyzed. EC was observed in 184 of 7736 cases (2.4% morbidity rate). Multivariate analysis revealed that significant risk factors for the development of EC were: diabetes mellitus {odds ratio (OR): 1.52}, proton pump inhibitor (PPI) use (OR: 1.69), atrophic gastritis (AG) (OR: 1.60), advanced gastric cancer (OR: 4.66), and gastrectomy (OR: 2.32). When severe EC (Kodsi grade ≥ II) was compared to mild EC (grade I), the most significant risk factors were advanced gastric cancer (OR: 17.6) and gastrectomy (OR: 23.4). When considering the risk of AG and PPI use with EC development, the risk increased as follows: AG (OR: 1.59), PPI use (OR: 2.25), and both (OR: 3.13). PPI use, AG, advanced gastric cancer and post-gastrectomy are critical risk factors for the development of EC. We suggest close monitoring for EC development when PPIs are administered to patients with these factors.

Fusobacterium nucleatum predicts a high risk of metastasis for esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer in China. The role of the bacteria present in ESCC tissue in neoplastic progression has not been fully elucidated. This study aimed to uncover different bacterial communities in ESCC tissues and examine the correlation between the abundance of the esophageal flora and clinicopathologic characteristics of ESCC. RESULTS: Microorganisms in tumors and normal tissues showed obvious clustering characteristics. The abundance of Fusobacterium (P = 0.0052) was increased in tumor tissues. The high level of Fusobacterium nucleatum was significantly associated with pT stage (P = 0.039) and clinical stage (P = 0.0039). The WES data showed that COL22A1, TRBV10-1, CSMD3, SCN7A and PSG11 were present in only the F. nucleatum-positive ESCC samples. GO and protein domain enrichment results suggested that epidermal growth factor might be involved in the regulation of cell apoptosis in F. nucleatum-positive ESCC. Both a higher mutational burden and F. nucleatum-positive was observed in tumors with metastasis than in tumors without metastasis. CONCLUSION: F. nucleatum is closely related to the pT stage and clinical stage of ESCC. The abundance of F. nucleatum and tumor mutation burden may be used in combination as a potential method to predict metastasis in ESCC.

Multi-omics of the esophageal microenvironment identifies signatures associated with progression of Barrett's esophagus.

BACKGROUND: The enrichment of Gram-negative bacteria of oral origin in the esophageal microbiome has been associated with the development of metaplasia. However, to date, no study has comprehensively assessed the relationships between the esophageal microbiome and the host. METHODS: Here, we examine the esophageal microenvironment in gastro-esophageal reflux disease and metaplasia using multi-omics strategies targeting the microbiome and host transcriptome, followed by targeted culture, comparative genomics, and host-microbial interaction studies of bacterial signatures of interest. RESULTS: Profiling of the host transcriptome from esophageal mucosal biopsies revealed profound changes during metaplasia. Importantly, five biomarkers showed consistent longitudinal changes with disease progression from reflux disease to metaplasia. We showed for the first time that the esophageal microbiome is distinct from the salivary microbiome and the enrichment of Campylobacter species as a consistent signature in disease across two independent cohorts. Shape fitting and matrix correlation identified associations between the microbiome and host transcriptome profiles, with a novel co-exclusion relationship found between Campylobacter and napsin B aspartic peptidase. Targeted culture of Campylobacter species from the same cohort revealed a subset of isolates to have a higher capacity to survive within primary human macrophages. Comparative genomic analyses showed these isolates could be differentiated by specific genomic features, one of which was validated to be associated with intracellular fitness. Screening for these Campylobacter strain-specific signatures in shotgun metagenomics data from another cohort showed an increase in prevalence with disease progression. Comparative transcriptomic analyses of primary esophageal epithelial cells exposed to the Campylobacter isolates revealed expression changes within those infected with strains with high intracellular fitness that could explain the increased likelihood of disease progression. CONCLUSIONS: We provide a comprehensive assessment of the esophageal microenvironment, identifying bacterial strain-specific signatures with high relevance to progression of metaplasia.

Comparison of Oral and Esophageal Microbiota in Patients with Achalasia Before and After Peroral Endoscopic Myotomy.

BACKGROUND/AIMS: Patients with achalasia have a high incidence of esophageal squamous cell carcinoma (ESCC), which may be associated with alterations in oral and esophageal microbiota caused by food stasis. This study compared the oral and esophageal microbiota of patients with achalasia before and after peroral endoscopic myotomy (POEM). It also compared patients with achalasia to those with ESCC. MATERIALS AND METHODS: The study prospectively examined 6 patients with achalasia and 14 with superficial ESCC. Oral samples obtained from the buccal mucosa using a swab and esophageal samples obtained from the mid-esophagus using a brush via endoscopy were analyzed by 16S rRNA metagenome sequencing. Additionally, endoscopic and histological findings of patients with achalasia before and after POEM were prospectively compared. RESULTS: In patients with achalasia, Streptococcus was most abundant in both the oral and the esophageal microbiota, and these microbiota were significantly different. Although the overall structure of the oral and esophageal microbiota did not change after POEM, the relative abundance rate of Haemophilus and Neisseria increased in the esophagus, and endoscopic findings of inflammation improved after POEM (P = .04). The relative abundance of microbiota was not different among patients with achalasia from those with ESCC. CONCLUSIONS: The oral and esophageal microbiota were significantly different in patients with achalasia, and some of the composition of the esophageal microbiota changed after POEM. However, these findings and disease-specific microbiota should be further evaluated in large-scale studies.

Esophageal microbiome in active eosinophilic esophagitis and changes induced by different therapies.

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory esophageal disease triggered by food antigens. Cumulative evidence supports the implication of microbiota and the innate immune system in the pathogenesis of EoE. Changes in the esophageal microbiome were investigated by applying 16S rRNA gene sequencing on esophageal biopsies of adult patients with active EoE at baseline (n = 30), and after achieving remission with either proton pump inhibitors (PPI, n = 10), swallowed topical corticosteroids (STC, n = 10) or food-elimination diets (FED, n = 10). Ten non-EoE biopsies were also characterized as controls. Compared to controls, no differences in alpha (intra-sample) diversity were found in EoE microbiota overall. However, it decreased significantly among patients who underwent FED. As for beta (inter-sample) diversity, non-EoE controls separated from EoE baseline samples. Post-treatment samples from patients treated with PPI and FED had a more similar microbiota composition, while those receiving STC were closer to controls. Differential testing of microbial relative abundance displayed significant changes for Filifactor, Parvimonas and Porphyromonas genera. Analysis of predicted functions indicated alterations in metabolic pathways and abundance of sulphur-cytochrome oxidoreductases. Our findings demonstrate changes in microbiota associated with EoE, as well as a treatment effect on the microbiome.

Microbiome of the Aerodigestive Tract in Health and Esophageal Disease.

The diverse human gut microbiome is comprised of approximately 40 trillion microorganisms representing up to 1000 different bacterial species. The human microbiome plays a critical role in gut epithelial health and disease susceptibility. While the interaction between gut microbiome and gastrointestinal pathology is increasingly understood, less is known about the interaction between the microbiome and the aerodigestive tract. This review of the microbiome of the aerodigestive tract in health, and alterations in microbiome across esophageal pathologies highlights important findings and areas for future research. First, microbiome profiles are distinct along the aerodigestive tract, spanning the oral cavity to the stomach. In patients with reflux-related disease such as gastro-esophageal reflux disease, Barrett's esophagus, and esophageal adenocarcinoma, investigators have observed an overall increase in gram negative bacteria in the esophageal microbiome compared to healthy individuals. However, whether differences in microbiome promote disease development, or if these shifts are a consequence of disease remains unknown. Interestingly, use of proton pump inhibitor therapy is also associated with shifts in the microbiome, with distinct shifts and patterns along the aerodigestive tract. The relationship between the human gut microbiome and esophageal pathology is a ripe area for investigation, and further understanding of these pathways may promote development of novel targets in prevention and therapy for esophageal diseases.

Isolation and characterization of the aerobic bacterial microbiota of the esophagus and its probable association with obstructive caseous lesions in green turtles (Chelonia mydas) / Isolamento e caracterização da microbiota bacteriana aeróbia do esôfago e sua provável associação com lesões caseosas obstrutivas em tartarugas-verdes (Chelonia mydas)

Caseous lesions in the esophagus of green turtles (Chelonia mydas) from the coast of Brazil have been described as obstructive lesions and can lead to the death of these animals. However, their etiology remains unclear. The aim of this study was to isolate and characterize the aerobic bacterial microbiota of the esophagus of green turtles (C. mydas) from the Brazilian coast and to verify its possible participation in the etiology of caseous lesions. For this, 42 animals were used, 33 alive and healthy and 9 naturally dead that had esophageal lesions confirmed by necropsy, from Anchieta and Piúma beaches, Espírito Santo. Microbiological tests and morphological evaluation of the esophagus were performed. We isolated 14 different bacterial agents from healthy animal samples, with the prevalence of Pseudomonas aeruginosa being (36.36%), Staphylococcus aureus (33.33%), Aeromonas hydrophila (27.27%), and Vibrio alginolyticus (24.24%). In dead animals, only three distinct agents were isolated: S. aureus (50.00%), A. hydrophila (25.00%), and V. alginolyticus (25.00%). Morphological evaluation revealed a predominance of the lesions at the gastroesophageal junction, with multifocal-to-coalescent distribution, discrete intensity, and absence of obstruction. Ulcerations and caseous exudates, inflammatory infiltrates, parasitic eggs, and giant foreign body cells were also observed as well as bacterial lumps and glandular alterations, such as necrosis, adenitis, and fragments of adult parasites. There was a positive correlation between bacterial lumps and microbiological culture and a negative correlation between bacterial lumps and microbiological culture with parasites. Thus, it was noted that the esophageal aerobic microbiota of C. mydas was predominantly composed of Gram-negative bacteria such as P. aeruginosa, A. hydrophila, and V. alginolyticus, in addition to several enterobacteria and Gram-positive bacteria, such as S. aureus. These agents are opportunists and may be involved in the etiology of caseous esophagitis in association with other pathogens as co-factors working in association or, even in a secondary way.(AU)

A ocorrência de lesão caseosa no esôfago de tartarugas-verdes (Chelonia mydas) da costa do Brasil tem sido descrita como de caráter obstrutivo e pode causar a morte dos animais. No entanto, sua etiologia permanece pouco esclarecida. Objetivou-se isolar e caracterizar a microbiota aeróbica esofágica das tartarugas-verdes (C. mydas) da costa brasileira e verificar sua possível participação na etiologia das lesões caseosas. Foram utilizados 42 animais, 33 vivos e hígidos e nove mortos naturalmente que apresentavam lesão esofágica confirmada pela necropsia, provenientes de Anchieta e Piúma, Espírito Santo, nos quais foram feitos testes microbiológicos e avaliação morfológica do esôfago. Foram isolados 14 agentes bacterianos diferentes nas amostras de animais saudáveis, com prevalência de Pseudomonas aeruginosa (36,36%), Staphylococcus aureus (33,33%), Aeromonas hydrophila (27,27%) e Vibrio alginolyticus (24,24%). Nos animais mortos, foram isolados apenas três agentes distintos: S. aureus (50,00%), A. hydrophila (25,00%) e V. alginolyticus (25,00%). A avaliação morfológica revelou predominância da lesão em junção gastroesofágica, com distribuição multifocal a coalescente, intensidade discreta e ausência de obstrução. Observou-se ainda ulceração e exsudato caseoso, infiltrado inflamatório, ovos de parasitos e células gigantes do tipo corpo estranho, além de grumos bacterianos e de alterações glandulares, como necrose, adenite e fragmentos de parasitos adultos. Houve correlação positiva dos grumos bacterianos com cultivo microbiológico e negativa dos grumos bacterianos e cultivo microbiológico com parasitos. Assim, nota-se que a microbiota esofágica aeróbica de C. mydas é constituída predominantemente por bactérias Gram-negativas como P. aeruginosa, A. hydrophila e V. alginolyticus, além de diversas enterobatérias e por Gram-positivas, como S. aureus. Esses agentes são oportunistas e podem estar envolvidos na etiologia da esofagite caseosa em associação a outros patógenos como co-fatores agindo em associação, ou mesmo, por via de infecção secundária.(AU)

Treatment of non-erosive reflux disease and dynamics of the esophageal microbiome: a prospective multicenter study.

Non-erosive reflux disease (NERD) pathogenesis has not been thoroughly evaluated. Here, we assessed the response of patients with NERD to proton pump inhibitor (PPI) therapy; changes in the microbiome and biologic marker expression in the esophageal mucosa were also evaluated. Patients with NERD (n = 55) received esomeprazole (20 mg) for eight weeks. The treatment response was evaluated at baseline, week four, and week eight. Esophageal mucosal markers and oropharyngeal and esophageal microbiomes were analyzed in patients who underwent upper gastrointestinal endoscopy at screening (n = 18). Complete and partial response rates at week eight were 60.0% and 32.7% for heartburn, and 61.8% and 29.1% for regurgitation, respectively. The expressions of several inflammatory cytokines, including IL-6, IL-8, and NF-κB, were decreased at week eight. Streptococcus, Haemophilus, Prevotella, Veillonella, Neisseria, and Granulicatella were prevalent regardless of the time-point (baseline vs. week eight) and organ (oropharynx vs. esophagus). The overall composition of oropharyngeal and esophageal microbiomes showed significant difference (P = 0.004), which disappeared after PPI therapy. In conclusion, half-dose PPI therapy for eight weeks could effectively control NERD symptoms. The expression of several inflammatory cytokines was reduced in the esophagus, and oropharyngeal and esophageal microbiomes in patients with NERD showed significant difference. However, the microbial compositions in the oropharynx and esophagus were not affected by PPI therapy in this study. Impact of PPI on the microbiome in patients with NERD should be more investigated in future studies.

Esophageal microbiome signature in patients with Barrett's esophagus and esophageal adenocarcinoma.

Preliminary studies suggested a possible correlation of microbiota with Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC), where the need for tools to ameliorate its poor prognosis is mandatory. We explored the potential signature of esophageal microbiota and its predicted functional profile along the continuous spectrum from BE to EAC. We analyzed through 16S-based amplicon sequencing the mucosal microbiota and the microbiota-related functional predictions in 10 BE and 6 EAC patients compared with 10 controls, exploring also potential differences between the metaplastic mucosa (BEM) and the adjacent normal areas of BE patients (BEU). BEM and EAC showed a higher level of α and ß-diversity. BEM evidenced a decrease of Streptococcus and an increase of Prevotella, Actinobacillus, Veillonella, and Leptotrichia. EAC displayed a striking reduction of Streptococcus, with an increase of Prevotella, Veillonella and Leptotrichia. LefSe analysis identified Leptotrichia as the main taxa distinguishing EAC. BEM showed a decreased α-diversity compared with BEU and a reduction of Bacteroidetes, Prevotella and Fusobacterium. Functional predictions identified peculiar profiles for each group with a high potential for replication and repair in BEM; an upregulated energy, replication and signaling metabolisms, with the fatty-acids biosynthesis and nitrogen and D-alanine pathways down-regulated in EAC. Our pilot study identifies a unique microbial structure and function profile for BE and EAC, as well as for metaplastic and near-normal areas. It proposes a new concept for BE, which could be intended not only as the histological, but, also, as the microbial closest precursor of EAC. This requires further larger follow-up studies, but opens intriguing horizons towards innovative diagnostic and therapeutic options for EAC.

[The state and role of esophagus, stomach, intestinal microbiota in patients with ulcer disease, chronic gastritis, esophagitis.]

The microflora of 64 biopsies taken during fibrogastroduodenoscopy of the mucous membrane of the esophagus, stomach and duodenum in healthy volunteers and 1120 samples obtained from the same parts of the digestive tract in patients with esophagitis, chronic gastritis and peptic ulcer disease were studied. The patients ranged in age from 18 to 62 years. Traditional bacteriological method was used to isolate and identify microorganisms. Staphylococcus spp., Streptococcus spp., Lactobacillus spp., Bacteroides spp., Stomatococcus spp., Enterobacteriaceae, Corynebacterium spp., Micrococcus spp., Neisseria spp., Veilonella spp. were isolated from biopsies of healthy respondents in an average amount from 3.2 to 4.68 lg CFU/g. H.pylori was found in 60% (5.66 lg CFU/g) in the esophagus, in 33.3% of cases (5.12 lg CFU/g) from the fundal part of the stomach, in 44.4% (5.25 lg CFU/g) from the antral part of the stomach, in 5.5% (4.2 lg CFU/g) in the duodenal mucosa. In samples obtained from the inflamed and eroded mucous membrane of the esophagus, stomach and duodenum, opportunistic bacteria of the genera Klebsiella, Enterobacter, Proteus, Pseudomonas, Peptococcus, Actinomyces, yeast fungi of the genus Candida etc. were detected in an amount exceeding 4 lg CFU/g. H. pylori isolated in 6.3-16.7% of patients (4.25-4.6 lg CFU/g) and did not dominate in relation to other microorganisms, and in most cases had a low frequency of its occurrence. In patients with the recurrence of peptic ulcer disease, exacerbation of chronic gastritis and esophagitis, dysbiosis was developed, characterized by an increase in the species and quantitative composition of opportunistic microflora, an increase in its enzymatic and cytotoxic activity, which can contribute to the maintenance of inflammatory and necrotic processes and inhibit the elimination of the pathological process.

The diagnosis of clinically significant oesophageal Candida infections: a reappraisal of clinicopathological findings.

AIMS: Distinguishing true oesophageal Candida infections from oral contaminants is a common diagnostic issue. Historically, histological features believed to indicate true infection included epithelial invasion by pseudohyphae and intraepithelial neutrophils. Whether or not these features correlate with endoscopic lesions, symptoms and response to therapy has never been tested in a large cohort. The aim of this study was to determine whether specific histological features correlate with clinical and endoscopic findings when Candida is found in oesophageal biopsies. METHODS AND RESULTS: We reviewed 271 biopsies in which Candida was detected. Cases were evaluated for the presence of desquamated epithelial cells, location/type of fungal forms, neutrophils, and ulceration. Medical records were reviewed for clinical history, endoscopic lesions, and response to antifungal therapy. Statistical analysis was used to determine whether any histological features significantly correlated with clinical variables. There were 120 males and 151 females with a mean age of 42 years. Fifty-nine per cent had symptoms referable to the oesophagus, particularly dysphagia (36%). Most (73%) patients had abnormal endoscopic findings, with plaques, ulcers, or macroscopic evidence of oesophagitis. Seventy-one per cent of patients with documented antifungal therapy showed symptomatic improvement. Overall, there was no statistically significant correlation between any histological feature and presenting symptoms, endoscopic findings, or response to therapy. Importantly, the lack of pseudohyphae, demonstrable invasion of intact epithelium or neutrophilic infiltrates did not exclude clinically significant infection. CONCLUSIONS: We conclude that detection of Candida in oesophageal biopsies is always potentially clinically significant. Treatment decisions should be made on the basis of an integration of clinical, endoscopic and histological findings.

Sarcina Organisms in the Upper Gastrointestinal Tract: A Report of 3 Cases With Varying Presentations.

Sarcina species are anaerobic gram-positive cocci rarely seen in the upper gastrointestinal tract and associated with delayed gastric emptying. We present 3 cases of Sarcina infection with varying clinical presentations including the first reported case of Sarcina in a patient with eosinophilic esophagitis. Although the pathogenesis of Sarcina is unclear, awareness of the bacteria is important as they can usually only be detected on histopathologic examination of upper gastrointestinal biopsies. Treatment in symptomatic patients may prevent severe complications such as emphysematous gastritis and gastric perforation.

Esophageal tuberculosis: A rare case report.

After a steady decline throughout the 20th century, the incidence of tuberculosis (TB) in industrialized countries has started to rise again. However, in developing countries like India, the menace of TB had never been controlled. Gastrointestinal (GI) TB is rare, and the GI tract is considered only the sixth most frequent site of extrapulmonary TB. Esophageal TB (ET) is still rarer. This is a case report of a rare form of ET in a patient presenting with dysphagia. The patient was subjected to upper GI endoscopy, which revealed an ulcerative growth in the distal esophagus. Histopathology revealed ET. The patient was managed conservatively with anti-TB treatment (ATT). In spite of the rare nature of the disease, it can be managed effectively with ATT to avoid complications (fistula, stricture, and esophageal perforation), which might warrant surgery.

Regional Diversity of the Gastrointestinal Microbiome.

The role of gut microbes in health and disease has often been surmised from stool, which is easily sampled and rich in microbial diversity, density, and abundance. Microbial analyses of stool have been accepted as measures to determine the relationship of gut microbiomes with host health and disease, based on the belief that it represents all microbial populations throughout the gut. However, functional heterogeneity of each gastrointestinal tract (GIT) segment gives rise to regional differences in gut microbial populations. Herein, we summarize the literature regarding the microbial landscape along the rostral to caudal, i.e., horizontal mouth to anus, axis of the GIT. We aim to identify gaps in the literature, particularly regarding small intestinal microbiota abundance and diversity, highlight the importance of regional microbiota on host health and disease, as well as discuss opportunities to advance this line of research.

[Advances in esophageal microbiota and esophageal related diseases].

Esophagus, as the pipe connecting oral cavity and stomach, has unique anatomical structure and physiological functions. The related diseases including esophageal cancer and precancerous lesions are the ones of major public health problems in China. The pathogenesis of esophageal diseases is still not clear. The exploration of correlation between the changes of esophageal microbiota and esophageal diseases becomes a new breakthrough in the study of etiology. Previous studies have found enrichment of gram-positive bacteria in the normal esophagus, while a decrease in diversity of bacteria and a dominant gram-negative anaerobe in diseased esophagus. Although much progress has been made in the study of esophageal microbiota, the standard method of how to accurately and noninvasively collect esophageal microbiota is still lack, which is an important part of the esophageal microbial research.

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.

Microbiota of the Oropharynx and Endoscope Compared to the Esophagus.

The role of the microflora in the development of esophageal disease is still largely unknown and is being investigated in more detail. Our goal was to determine how the microbiota levels of endoscope and uvular swabs compared to the levels of tissue biopsies along various points of the esophagus. 17 patients with Barrett's esophagus agreed to participate in the study. Biopsies of esophageal mucosa were taken from the (1) proximal esophagus, (2) mid-esophagus, (3) distal esophagus, and (4) Barrett's esophagus. Swabs were also taken from the uvula and the endoscope. Throughout the esophagus, 17 bacterial genera were detected from the samples. The microflora pattern obtained from the uvula and endoscopic swabs did not correlate well with mucosal biopsies along any aspect of the esophagus. There were statistically significant differences in the levels and proportions of bacteria found when comparing the uvula swab to the esophageal biopsies and when comparing the endoscope swab to the esophageal biopsies. Obtaining a simple swab of the uvula or endoscope itself appears to be a poor substitute for tissue biopsy of esophageal mucosa when evaluating microflora patterns. When performing microflora studies of the esophagus, mucosal biopsies should be used for analysis.