Changes in gastric and lung microflora with acid suppression: acid suppression and bacterial growth

Prevalence, risk factors, and treatment of small intestinal bacterial overgrowth in children

Small intestinal bacterial overgrowth (SIBO) is defined as the presence of an excessive number of bacteria within the small bowel. Pediatric SIBO is a heterogeneous disorder that manifests as various symptoms ranging from mild gastrointestinal symptoms to malabsorption or malnutrition. The carbohydrate breath test is a commonly used, safe, and noninvasive diagnostic test; however, a standardized methodology is lacking. Multiple factors, such as neuromuscular disorders, systemic diseases, chronic drug use, or altered intestinal anatomy that disturb intestinal motility or induce an abnormality in the body's defense systems against intestinal bacteria, predispose children to SIBO. The high prevalence and similar symptoms of SIBO in functional gastrointestinal disorders, including irritable bowel syndrome, suggest an association between them. The principles of treatment include managing predisposing conditions, nutritional support, symptom control, and antibacterial treatment. Rifaximin is the most commonly used drug. To date, studies of antibiotic treatment in pediatric populations with irritable bowel syndrome or SIBO are lacking and have shown mixed results. Here we review the prevalence, diagnostic tests, and treatment results in pediatric populations.

Gastric juice microbiota in pediatric chronic gastritis that clinically tested positive and negative for Helicobacter pylori

Purpose

Helicobacter pylori (HP) infection is an identified risk factor for pediatric chronic gastritis (PCG), but its impact on gastric juice microbiota (GJM) remains to be further elucidated in PCG. This study aimed to analyze and compare the microbial communities and microbial interactive networks of GJM in PCG that clinically tested positive and negative for HP (HP+ and HP-, respectively).

Methods

A total of 45 PCG patients aged from 6 to 16 years were recruited, including 20 HP+ and 25 HP- patients tested by culture and rapid urease test. Gastric juice samples were collected from these PCG patients and subjected to high-throughput amplicon sequencing and subsequent analysis of 16S rRNA genes.

Results

While no significant change in alpha diversity, significant differences in beta diversity were observed between HP+ and HP- PCG. At the genus level, Streptococcus, Helicobacter, and Granulicatella were significantly enriched in HP+ PCG, whereas Campylobacter and Absconditabacteriales (SR1) were significantly enriched in HP- PCG. Network analysis showed that Streptococcus was the only genus positively correlated with Helicobacter (r = 0.497) in the GJM network of overall PCG. Moreover, compared to HP- PCG, HP+ PCG showed a reduction in microbial network connectivity in GJM. Netshift analysis identified driver microbes including Streptococcus and other four genera, which substantially contributed to the GJM network transition from HP- PCG to HP+ PCG. Furthermore, Predicted GJM function analysis indicated up-regulated pathways related to the metabolism of nucleotides, carbohydrates, and L-Lysine, the urea cycle, as well as endotoxin peptidoglycan biosynthesis and maturation in HP+ PCG.

Conclusion

GJM in HP+ PCG exhibited dramatically altered beta diversity, taxonomic structure, and function, with reduced microbial network connectivity, which could be involved in the disease etiology.

Gastroesophageal Reflux Treatment in Infancy Through Young Adulthood

Gastroesophageal reflux treatment varies greatly across the pediatric age spectrum. Infant reflux treatments rely heavily on nutritional interventions, whereas reflux in older children is treated more commonly with medications. However, because of the broad differential diagnosis, treatment nonresponse merits a re-evaluation of the diagnosis being treated and additional testing to provide a more precision-medicine approach to care.

Gastrointestinal Symptom Improvement for Infants Following Tongue-Tie Correction

Treatment of tongue-tie in infants suggests improvements for breastfeeding mothers, including reduced nipple pain and improved latching onto the breast. The effects of frenotomy on infant feeding and gastrointestinal dysfunction remain controversial, with insufficient evidence on the relationship between tongue-tie and disorders of the gastrointestinal tract. The purpose of this study was to compare symptoms of gastrointestinal (GI) distress and gastroesophageal reflux (GER) prior to and 2 weeks following frenotomy in infants with tongue-tie. Parents were surveyed prior to frenotomy and 2 weeks post procedure, using the Gastrointestinal and Gastroesophageal Reflux (GIGER) Scale for Infants and Toddlers. Eighty-four participants completed surveys at both time points, with significant improvements in GI and GER symptoms 2 weeks after frenotomy. Younger infants and those with more severe tongue-tie had the greatest improvements in GI and GER symptoms. Infants with tongue-tie and symptoms of GI tract distress may experience improvement in symptoms after frenotomy.

Association between proton-pump inhibitors and the risk of gastric cancer: a systematic review and meta-analysis

BACKGROUND

Proton pump inhibitors (PPIs) may be associated with gastric cancer, but studies in recent years have proven still inconsistent results. We conducted a systematic review and meta-analysis to investigate the association between PPI use and gastric cancer.

METHODS

Pubmed, EMBASE, and Cochrane library were searched for studies published up to 15th February 2022. Studies on the association between PPI and the risk of gastric cancer, pooled the odds ratios (ORs) using a random-effects model. The subgroup analysis for study design, site of gastric cancer, and the duration of PPI use was performed. Heterogeneity was assessed using the I² and Cochran's Q statistics.

RESULTS

Sixteen cohorts and case-control studies were included. PPI use was significantly associated with gastric cancer (OR: 1.75, 95% CI: 1.28-2.40). The subgroup analysis found a significant risk increase in non-cardia gastric cancer (OR: 2.14, 95%CI: 1.50-3.07). There was no duration-dependent effect of PPI use and gastric cancer risk (< 1 year: OR: 2.56, 95% CI: 1.41-4.64, I² = 98%; 1-3 years: OR: 1.47, 95% CI: 1.26-1.71, I² = 41%; > 3 years: OR: 1.58, 95% CI: 1.16-2.14, I² = 74%).

CONCLUSIONS

PPIs were significantly associated with an increased risk of gastric cancer. However, this association does not confirm causation. Several well-design studies are needed to confirm the findings in the future.

La prise en charge médicale du reflux gastro-œsophagien chez les nourrissons en santé

Les symptômes cliniques attribués au reflux gastro-œsophagien pathologique chez les nourrissons nés à terme et en santé sont non spécifiques et rappellent des comportements adaptés à l’âge. Le présent point de pratique analyse les données probantes sur la prise en charge médicale recommandée de cette affection courante. Les recommandations à jour en vue de la prise en charge de ce type de reflux comprennent les modifications à l’alimentation, telles que l’épaississement des aliments ou l’évitement des protéines du lait de vache. Les données probantes à l’égard d’une prise en charge pharmacologique, y compris les traitements antiacides ou les agents procinétiques, sont limitées et démontrent que leurs risques sont souvent supérieurs à leurs éventuels avantages en raison des importantes préoccupations liées à l’innocuité et aux effets secondaires. Les traitements antiacides ne doivent pas être utilisés systématiquement chez les nourrissons présentant un reflux gastro-œsophagien pathologique. Ils sont plus susceptibles d’être utiles pour soigner des symptômes évocateurs d’une œsophagite érosive. Les données probantes sur la prise en charge des symptômes attribués à ce type de reflux chez les nourrissons de moins d’un an qui sont nés à terme et sont autrement en santé sont exposées, et la surprescription de médicaments est déconseillée dans cette population. Les conseils préventifs sur la résolution naturelle des symptômes de reflux sont recommandés.

Medical management of gastro-esophageal reflux in healthy infants

Clinical symptoms attributed to gastro-esophageal reflux disease (GERD) in healthy term infants are non-specific and overlap with age-appropriate behaviours. This practice point reviews the evidence for medically recommended management of this common condition. Current recommendations to manage GERD include feeding modifications such as thickening feeds or avoiding cow's milk protein. There is limited evidence for pharmacological management, including acid suppressive therapy or prokinetic agents, with the risks of such treatments often outweighing possible benefits due to significant safety and side effect concerns. Acid-suppressive therapy should not be routinely used for infants with GERD and is most likely to be useful in the context of symptoms that suggest erosive esophagitis. Evidence for managing symptoms attributed to GERD in otherwise healthy term infants less than 1 year of age is presented, and the over-prescription of medications in this population is discouraged. Anticipatory guidance regarding the natural resolution of reflux symptoms is recommended.

A literature review on the potential clinical implications of streptococci in gastric cancer

Streptococcus is widely found in nature and the human body, and most species are not pathogenic. In recent years, studies have found that Streptococcus is associated with gastric cancer. Streptococcus was found to be enriched in the oral cavity, stomach and intestine of gastric cancer patients and found to be increased in gastric cancer tissues, suggesting that Streptococcus may be the pathogenic bacteria underlying gastric cancer. This review discusses the discovery of Streptococcus, the relationship between Streptococcus and gastric cancer, and the possible carcinogenic mechanism of Streptococcus and summarizes the progress of the research on the role of Streptococcus in gastric cancer to provide new ideas for the early detection, diagnosis and treatment of gastric cancer.

Association of Serum Pepsinogens With Esophageal Squamous Cell Carcinoma Risk: A Systematic Review and Meta-Analysis

Background

Serum pepsinogens are serological biomarkers of gastric atrophy, and the latter is a risk factor for esophageal squamous cell carcinoma (ESCC). However, the association of serum pepsinogens with ESCC risk remains unclear. This systematic review and meta-analysis aimed to assess the relationship between serum pepsinogen I (PGI) and pepsinogen I: pepsinogen II ratio (PGR) and ESCC risk.

Methods

PubMed, Embase, and Web of Science were searched for articles on the effect of serum PGI and PGR on ESCC risk, published up to the end of February 2022. Meta-analysis with a random-effect model was used to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Five case–control studies and three prospective studies were included. In comparison with the high categories, the low categories of serum PGI (OR: 1.92, 95% CI: 1.45–2.56) and PGR (OR: 1.70, 95% CI: 1.01–2.85) were associated with an increased risk of ESCC, although a substantial heterogeneity was observed in serum PGR (I² = 60.2%, P = 0.028) rather than in serum PGI (I² = 46.4%, P = 0.070). In stratified analysis by study quality, the significant risk effect on ESCC was remained for PGI (OR: 2.05, 95% CI: 1.48–2.84) and PGR (OR: 2.07, 95% CI: 1.17–3.75) when only the studies with high quality were pooled.

Conclusions

Based on the available studies, although limited in number, this systematic review along with meta-analysis suggests that low serum PGI and low PGR may be related to an increased risk of ESCC. This present study provides evidence for using serum pepsinogen biomarkers in predicting ESCC. More delicate well-designed cohort studies with high study quality are needed, and dose–response analysis should be performed.

Impact of Coronavirus Disease 2019 on the Pediatric Population with Aerodigestive Disease

OBJECTIVE

To determine the impact of the coronavirus disease 2019 (COVID-19) quarantine on baseline health, medication use, health anxiety, and healthcare use in pediatric patients with aerodigestive disease and to evaluate for associations of commonly prescribed medications with the risk of COVID-19 illness.

STUDY DESIGN

Prospective study of patients presenting in person to pediatric neurogastroenterology clinics between July 2020 and March 2021.

RESULTS

Of 202 recruited patients, 71.3% were seen in the aerodigestive diseases center and 28.7% in the functional abdominal pain (FAP)/motility clinic. Of all patients, 25.1% reported improved overall health during quarantine; patients with aerodigestive disease (35.3%) reported higher rates of improved overall health compared with patients with FAP/motility disorders (3.6%, P = .0001). Patients with aerodigestive disease had fewer airway symptoms (P < .05) and less medication use during quarantine (inhaled steroids, P < .05 and albuterol, P < .05). Despite objective improvement, there was significant health-related anxiety, with greater anxiety scores reported during and at the end of quarantine (P < .05), with no difference between patient groups (P > .11). Patients continued to access healthcare during quarantine. In total, 28.7% of patients were seen in the emergency department (patients with FAP more than patients with aerodigestive disease, P = .02), and 19.8% were hospitalized. COVID-19 testing was performed in 58.4% of patients and 2.0% (n = 4) of the entire cohort tested positive.

CONCLUSIONS

Patients with aerodigestive disease show improvement of airway symptoms and decreased use of medications during the pandemic, despite increased health-related anxiety. Despite complexities of accessing care due to the widespread lockdown, all patient groups continued to access healthcare.

Probiotics and Functional Gastrointestinal Disorders in Pediatric Age: A Narrative Review

Assessment and management of pain are essential components of pediatric care. Pain in pediatric age is characterized by relevant health and socio-economic consequences due to parental concern, medicalization, and long-term physical and psychological impact in children. Pathophysiological mechanisms of nociception include several pathways in which also individual perception and gut-brain axis seem to be involved. In this narrative review, we analyze the rational and the current clinical findings of probiotic use in the management of functional gastrointestinal disorders (FGID) in pediatric age, with special focus on infantile colic, irritable bowel syndrome, constipation, and gastroesophageal reflux. Some specific probiotics showed a significant reduction in crying and fussing compared to placebo in breastfed infants with colic, although their exact mechanism of action in this disorder remains poorly understood. In irritable bowel syndrome, a limited number of studies showed that specific strains of probiotics can improve abdominal pain/discomfort and bloating/gassiness, although data are still scarce. As for constipation, whilst some strains appear to reduce the number of hard stools in constipated children, the evidence is not adequate to support the use of probiotics in the management of functional constipation. Similarly, although some probiotic strains could promote gastric emptying with a potential improvement of functional symptoms related to gastroesophageal reflux, current evidence is insufficient to provide any specific recommendation for the prevention or treatment of gastroesophageal reflux. In conclusion, probiotics have been proposed as part of management of pain in functional gastrointestinal disorders in pediatric age, but mechanisms are still poorly understood and evidence to guide clinical practice is currently inadequate.

Novel Advances in the Evaluation and Treatment of Children With Symptoms of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease has long been implicated as a cause for multiple pediatric symptoms ranging from abdominal pain and regurgitation to cough and dental erosions. Diagnostic testing has evolved greatly over the last 20 years; initial testing with pH-metry to measure esophageal acid reflux burden has evolved into measurement of both acid and non-acid reflux and liquid and gas reflux. However, measuring reflux burden alone only tells a small part of the GERD story and many symptoms originally thought to be reflux related are, in fact, related to other disorder which mimic reflux. The current paradigm which involves empiric treatment of symptoms with acid suppression has been replaced with early testing for not only gastroesophageal reflux but also for other diagnostic masqueraders. The focus for interventions has shifted away from acid suppression toward motility interventions and includes a greater recognition of both functional and motility disorders which present with reflux symptoms.

The impact of Helicobacter pylori infection, eradication therapy, and probiotics intervention on gastric microbiota in young adults

BACKGROUND

The impact of probiotics on non-Helicobacter pylori gastric microbiota and its role in microbial restoration after eradication were relatively unknown. We aimed to explore the effect of H. pylori eradication and probiotic intervention on gastric microbiota in young adults.

METHODS

Fifty-six H. pylori-negative and 95 H. pylori-positive subjects aged 19-30 were included in this study. H. pylori-infected individuals were randomly assigned to quadruple therapy, probiotics supplemented quadruple therapy, or probiotics monotherapy group. Gastric mucosa and gastric juice samples were collected before and 2 months after treatment for 16SrRNA gene sequencing.

RESULTS

The gastric microbial community structure and composition differed from H. pylori-negative subjects 2 months after successful H. pylori eradication. The α diversity of gastric mucosal microbiota significantly increased and was higher than H. pylori-negative subjects, while the α diversity of gastric juice microbiota decreased and was lower than the H. pylori-negative. After probiotics supplemented eradication treatment, Bifidobacterium was enriched in gastric mucosa, Lactobacillus was enriched in gastric juice, potentially pathogenic bacteria such as Fusobacterium and Campylobacter decreased, and the microbial diversity was closer to that of H. pylori-negative subjects compared to quadruple therapy group. Probiotics monotherapy significantly altered the diversity, community structure, and composition of gastric microbiota but showed no advantage in H. pylori inhibition and upregulating beneficial bacteria such as Bifidobacterium and Lactobacillus and related metabolism pathways. Certain potentially pathogenic bacteria such as Fusobacterium increased after probiotic monotherapy.

CONCLUSION

H. pylori eradication significantly disrupted gastric microbiota in young adults and could not be restored in a short time. Probiotics supplementation partially helped restore the gastric dysbiosis caused by eradication therapy, but it might be unnecessary for H. pylori-infected young adults to take probiotics alone.

Gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GERD) is a common disorder in adults and children. The global prevalence of GERD is high and increasing. Non-erosive reflux disease is the most common phenotype of GERD. Heartburn and regurgitation are considered classic symptoms but GERD may present with various atypical and extra-oesophageal manifestations. The pathophysiology of GERD is multifactorial and different mechanisms may result in GERD symptoms, including gastric composition and motility, anti-reflux barrier, refluxate characteristics, clearance mechanisms, mucosal integrity and symptom perception. In clinical practice, the diagnosis of GERD is commonly established on the basis of response to anti-reflux treatment; however, a more accurate diagnosis requires testing that includes upper gastrointestinal tract endoscopy and reflux monitoring. New techniques and new reflux testing parameters help to better phenotype the condition. In children, the diagnosis of GERD is primarily based on history and physical examination and treatment vary with age. Treatment in adults includes a combination of lifestyle modifications with pharmacological, endoscopic or surgical intervention. In refractory GERD, optimization of proton-pump inhibitor treatment should be attempted before a series of diagnostic tests to assess the patient's phenotype.

The Role of Microbiota in Primary Sclerosing Cholangitis and Related Biliary Malignancies

Primary sclerosing cholangitis (PSC) is an immune-related cholangiopathy characterized by biliary inflammation, cholestasis, and multifocal bile duct strictures. It is associated with high rates of progression to end-stage liver disease as well as a significant risk of cholangiocarcinoma (CCA), gallbladder cancer, and colorectal carcinoma. Currently, no effective medical treatment with an impact on the overall survival is available, and liver transplantation is the only curative treatment option. Emerging evidence indicates that gut microbiota is associated with disease pathogenesis. Several studies analyzing fecal and mucosal samples demonstrate a distinct gut microbiome in individuals with PSC compared to healthy controls and individuals with inflammatory bowel disease (IBD) without PSC. Experimental mouse and observational human data suggest that a diverse set of microbial functions may be relevant, including microbial metabolites and bacterial processing of pharmacological agents, bile acids, or dietary compounds, altogether driving the intrahepatic inflammation. Despite critical progress in this field over the past years, further functional characterization of the role of the microbiota in PSC and related malignancies is needed. In this review, we discuss the available data on the role of the gut microbiome and elucidate important insights into underlying pathogenic mechanisms and possible microbe-altering interventions.

Metabolomic profiling of extraesophageal reflux disease in children

Although respiratory symptoms in children are often attributed to gastroesophageal reflux disease, establishing a clear diagnosis of extraesophageal reflux disease (EERD) can be challenging, as there are no sensitive or specific EERD biomarkers. The aim of this study was to evaluate the metabolite profile in bronchoalveolar (BAL) fluid from children with suspected EERD and assess the impact of reflux treatment on these metabolites. In this prospective pilot study, we performed nontargeted global metabolomic profiling on BAL fluid from 43 children undergoing testing with bronchoscopy, upper endoscopy, and multichannel intraluminal impedance with pH (pH-MII) for evaluation of chronic respiratory symptoms. Twenty-three (54%) patients had an abnormal pH-MII study. Seventeen (40%) patients were on proton pump inhibitors (PPIs) for testing. Levels of histamine, malate, adenosine 5'-monophosphate, and ascorbate were significantly lower in subjects with abnormal pH-MII studies compared to those normal studies. Furthermore, in children off PPI therapy, those with abnormal pH-MII studies had robust increases in a number of glycerophospholipids within phospholipid metabolic pathways, including derivatives of glycerophosphorylcholine, glycerophosphoglycerol, and glycerophosphoinositol, compared to those with normal pH-MII studies. These findings offer insight into the impact of reflux and PPIs on the lungs and provide a foundation for future studies using targeted metabolomic analysis to identify potential biomarkers of EERD.

Impact of Environmental and Pharmacologic Changes on the Upper Gastrointestinal Microbiome

Diseases of the upper gastrointestinal tract have become more prevalent over time. Mechanisms of disease formation are still only partially understood. Recent literature has shown that the surrounding microbiome affects the propensity for disease formation in various parts of the upper gastrointestinal tract. A review was performed of any literature to our best knowledge concerning the effects of pharmacologic agents, environmental changes, and surgical intervention on the microbiome of the upper gastrointestinal tract. Searches of the literature were performed using specific keywords related to drugs, surgical procedures, and environmental factors. Many prescription and nonprescription drugs that are commonly used have varying effects on the upper gastrointestinal tract. Proton pump inhibitors may affect the relative prevalence of some organisms in the lower esophagus and have less effect in the proximal esophagus. Changes in the esophageal microbiome correlate with some esophageal diseases. Drugs that induce weight loss have also been shown to affect the microbiomes of the esophagus and stomach. Common surgical procedures are associated with shifts in the microbial community in the gastrointestinal tract. Environmental factors have been shown to affect the microbiome in the upper gastrointestinal tract, as geographic differences correlate with alterations in the microbiome of the gastrointestinal tract. Understanding the association of environmental and pharmacologic changes on the microbiome of the upper gastrointestinal tract will facilitate treatment plans to reduce morbidity from disease.

Drugs in Focus: Proton Pump Inhibitors

Proton pump inhibitors (PPIs) are amongst the most commonly prescribed drugs in infants and children with the last decades witnessing a dramatic rise in their utilization. Although PPIs are clearly effective when used appropriately and have been regarded as safe drugs, there is growing evidence regarding their potential adverse effects. Although, largely based on adult data it is clear that many of these are also relevant to pediatrics. PPI use potentially affects gastrointestinal microbiota composition and function, decreases defence against pathogens resulting in increased risk for infections, interferes with absorption of minerals and vitamins leading to specific deficiencies and increased risk for bone fractures as well as interferes with protein digestion resulting in increased risk of sensitization to allergens and development of allergic diseases and eosinophilic esophagitis. An association with gastric, liver and pancreatic cancer has also been inferred from adult data but is tenuous and causation is not proven. Overall, evidence for these adverse events is patchy and not always compelling. Overall, the use of PPIs, for selected indications with a good evidence base, has significant potential benefit but carries more caution in infants and children. Pediatricians should be aware of the concerns regarding the potential adverse events associated with their use.

The risk of community-acquired pneumonia in children using gastric acid suppressants

BACKGROUND

With the increased use of acid suppressants, significant potential complications such as community-acquired pneumonia (CAP) are becoming more apparent. Paradoxically, in spite of an increased focus on potential complications, there is an increased use of acid suppressants in children and a lack of data specifically targeting the association between acid suppressants and CAP. Our main objective was to evaluate the risk of CAP in children using acid suppressants (proton pump inhibitors (PPIs) and/or histamine-2 receptor antagonists (H2RAs)).

METHODS

We performed a cohort study using data from the UK Clinical Practice Research Datalink. All patients aged 1 month to 18 years with a prescription of acid suppressants were included and matched to up to four unexposed children. Time-varying Cox proportional hazards models were used to estimate the risk of CAP. The cohort consisted of 84 868 exposed and 325 329 unexposed children.

RESULTS

Current use of PPIs and H2RAs was associated with an increased risk of CAP (adjusted hazard ratio 2.05 (95% CI 1.90-2.22) and 1.80 (95% CI 1.67-1.94), respectively). The risk was even greater in patients with respiratory disease. Long-term use (≥211 days) of PPIs and H2RAs led to a significantly greater risk of CAP compared with short-term use (<31 days). After cessation of therapy, the risk remained increased for the following 7 months.

CONCLUSION

The use of acid suppressants in children was associated with a doubled risk of CAP. This risk increased with chronic use and respiratory disease, and remained increased after discontinuation of therapy.

Dysbiosis, malnutrition and enhanced gut-lung axis contribute to age-related respiratory diseases

Older people are at an increased risk of developing respiratory diseases such as chronic obstructive pulmonary diseases, asthma, idiopathic pulmonary fibrosis or lung infections. Susceptibility to these diseases is partly due to the intrinsic ageing process, characterized by genomic, cellular and metabolic hallmarks and immunosenescence, and is associated with changes in the intestinal microbiota. Importantly, in the lungs, ageing is also associated with a dysbiosis and loss of resilience of the resident microbiota and alterations of the gut-lung axis. Notably, as malnutrition is often observed in the elderly, nutrition is one of the most accessible modifiable factors affecting both senescence and microbiota. This article reviews the changes affecting the lung and its resident microbiota during ageing, as well as the interconnections between malnutrition, senescence, microbiota, gut-lung axis and respiratory health. As the communication along the gut-lung axis becomes more permissive with ageing, this review also explores the evidence that the gut and lung microbiota are key players in the maintenance of healthy lungs, and as such, are potential targets for nutrition-based preventive strategies against lung disease in elderly populations.

[Gastric bacterial overgrowth: An unusual histological observation, not to be overlooked]

Gastric bacterial overgrowth is a rare situation, which may be associated with short- and long-term complications. It must be known from pathologists, since it might be detected incidentally at histological examination of gastric biopsies. We report here the case of a 74-year old woman, obese, without significant medical history, apart from a gastro-esophageal reflux treated by the long-term administration of proton pump inhibitors (PPI). In this patient, gastric bacterial overgrowth was detected at histological examination of gastric biopsies performed after colectomy for left colon adenocarcinoma. Large clusters of small, round, "coccoid" bacteria were present in the gastric mucus. Their characteristics were suggestive of enterobacteria. Bacterial proliferation was associated with severe and diffuse lesions of active gastritis. The course was rapidly unfavorable, and the patient rapidly deceased with multiple infections and multi-organ failure. In our observation, the pathogenesis of gastric bacterial overgrowth was probably multifactorial. It might have been facilitated by long-term PPI treatment and obesity, which are known risk factors, and promoted, in the post-operative setting, by multiple infections and immune failure. Our observation underlines that gastric bacterial overgrowth might be associated with severe gastritis, which might justify antibiotherapy. Other consequences of prolonged gastric dysbiosis cannot be excluded, such as the promotion of neoplastic lesions.

The impact of gastrointestinal dysmotility on the aerodigestive microbiome of pediatric lung transplant recipients

BACKGROUND

Delayed gastric emptying has been associated with increased graft rejection, although the mechanism of this association is not known. This study aims to investigate the interrelationship between delays in gastrointestinal motility and the diversity and composition of gastric, oropharyngeal, and lung microbiomes in pediatric lung transplant recipients.

METHODS

We prospectively recruited 23 pediatric lung transplant recipients and 98 pediatric patients with respiratory symptoms undergoing combined endoscopy and bronchoscopy. Gastric, oropharyngeal, and bronchoalveolar lavage samples were collected for 16S sequencing. Gastric samples were also analyzed for bile composition using liquid chromatography.

RESULTS

Patients who underwent lung transplantation had significantly reduced alpha diversity in gastric and oropharyngeal sites compared with patients with respiratory symptoms. This reduction in alpha diversity was especially evident in gastric samples in patients with delayed gastric emptying defined as abnormal gastric emptying on nuclear scintigraphy or as an elevation in gastric bile concentration (p ≤ 0.05). Whereas monocolonies were seen in the lungs of patients who underwent transplantation, these were not the same microbes seen in the stomach; the microbial overlap between lung and gastric samples within patients was low, and data indicated high individual variation between lung transplant recipients. Other contributors to reduced alpha diversity included antibiotics in combination with proton pump inhibitors, especially in gastric and oropharyngeal samples.

CONCLUSIONS

Lung transplant recipients have reduced microbial diversity in gastric fluid (GF) and oropharynx compared with patients who did not undergo lung transplantation. The decreased alpha diversity in GF may be associated with dysmotility.

Gastric Flora in Gastrostomy Fed Children with Neurological Impairment on Antacid Medication

This prospective cohort study aimed to: (1) describe types, concentrations and sensitivity profiles of bacteria found in gastric aspirates of neurologically impaired children; (2) compare flora between outpatients and those admitted with aspiration pneumonia; and (3) examine predictors of bacterial colonization. Gastric aspirates from gastrostomy fed, neurologically impaired children on antacid medication were measured for pH and sent for microbiological testing. The outpatient arm included 26 children at their baseline; the inpatient arm included 31 children with a clinical diagnosis of aspiration pneumonia. Descriptive statistics summarized the ecology and resistance patterns of microbial flora. Predictors of total bacterial colonization were explored with linear regression. High concentrations of potentially pathogenic fecal-type bacteria were detected in 50/57 (88%) gastric aspirates. pH was found to be the only predictor of bacterial growth; children with gastric pH ≥ 4 had significantly higher concentrations of aerobic growth, while those with no bacterial growth had a pH < 4. Further studies to evaluate optimal gastric pH, the role of gastric bacteria in causing aspiration pneumonia, and the optimal empiric therapy for aspiration pneumonia are recommended.

Distinct Microbiota Dysbiosis in Patients with Non-Erosive Reflux Disease and Esophageal Adenocarcinoma

Non-erosive reflux disease (NERD) and esophageal adenocarcinoma (EAC) are often regarded as bookends in the gastroesophageal reflux disease spectrum. However, there is limited clinical evidence to support this disease paradigm while the underlying mechanisms of disease progression remain unclear. In this study, we used 16S rRNA sequencing and mass-spectrometer-based proteomics to characterize the esophageal microbiota and host mucosa proteome, respectively. A total of 70 participants from four patient groups (NERD, reflux esophagitis, Barrett’s esophagus, and EAC) and a control group were analyzed. Our results showed a unique NERD microbiota composition, distinct to control and other groups. We speculate that an increase in sulfate-reducing Proteobacteria and Bacteroidetes along with hydrogen producer Dorea are associated with a mechanistic role in visceral hypersensitivity. We also observed a distinct EAC microbiota consisting of a high abundance of lactic acid-producing bacteria (Staphylococcus, Lactobacillus, Bifidobacterium, and Streptococcus), which may contribute towards carcinogenesis through dysregulated lactate metabolism. This study suggests the close relationship between esophageal mucosal microbiota and the appearance of pathologies of this organ.

The association between acid-suppressive agent use and the risk of cancer: a systematic review and meta-analysis

BACKGROUND

Acid-suppressive agents (ASAs) may be associated with cancer; previous studies reported that the risk of cancer with acid suppressants has differed depending on the site of cancer. Here, we conducted a systematic review and meta-analysis of the association between ASA use and the type of cancer risk.

METHODS

MEDLINE, EMBASE, and Cochrane library databases were searched for publications up to the end of September 2019 for MeSH terms and text words related to cancer and ASAs. Studies on the association between ASAs and cancer risk, which included a control group and reported the relative risk of cancer, were included. The inverse-variance random effect model was used to estimate the pooled relative risk (RR) and 95% confidence interval (CI), and subgroup analysis for type of acid suppressants, drug uptake duration, and cumulative doses was performed. Heterogeneity was assessed using the I² test and Q statistic.

RESULTS

Thirty-nine cohort and case-control studies were included. ASA use was found to be significantly associated with a 46% higher risk of gastric cancer (RR, 1.46; 95% CI, 1.18-1.80) and a 53% higher risk of liver cancer (RR, 1.53; 95% CI, 1.31-1.78) compared with nonuse; however, there was no significant association for esophageal, colorectal, pancreatic, lung, breast, prostate, and kidney cancer; melanoma; and lymphoma.

CONCLUSIONS

ASAs were significantly associated with an increased risk of gastric and liver cancer; therefore, special attention of ASA use considering the potential risk of gastric and liver cancer is needed.

Colonization by Pseudomonas aeruginosa and Staphylococcus aureus of Antral Biopsy Specimens from Gastritis Patients Uninfected with Helicobacter Pylori

Purpose

Roles and incidence of some microorganisms that transiently or permanently colonize the human stomach are still unknown despite advances in gastroenterology. We aimed to examine the incidence of four microorganisms, Helicobacter pylori, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, in the antral biopsy specimens of patients with gastroduodenal conditions.

Patients and Methods

Patients (67 females, 33 males; mean age = 49.5 years) were initially examined and diagnosed by a gastroenterologist at the Mehrad Hospital, Tehran, Iran. We enrolled those who underwent the upper gastrointestinal endoscopy because of gastroduodenal conditions. Two antral biopsy samples were taken by endoscopy; the first sample was used for the “rapid urease test” to confirm H. pylori. The second was used for DNA extraction and PCR analyses with specific, corresponding primer sets to establish the presence of the four microorganisms. Our study was approved by the Ethics Committee at the Tarbiat Modares University, Tehran.

Results

Based on pathology and endoscopy findings, we divided the patients into three groups: 62 presented with gastritis, 18 with duodenal ulcer, and 20 gastric ulcer. The number of patients with P. aeruginosa but without H. pylori significantly differed from the number of those co-infected with both microorganisms (P = 0.03). Additionally, a similar significance was found between the incidence of S. aureus in patients without H. pylori and those with both infections (P = 0.04). Our results indicated that a significant number of patients with gastritis were colonized with P. aeruginosa or S. aureus without being co-infected with H. pylori (P < 0.001). Interestingly, the incidence of colonization by P. aeruginosa of patients without H. pylori (45/49, 91.8%) was higher than that by S. aureus (28/49, 57%).

Conclusion

The number of patients without H. pylori but with P. aeruginosa or with S. aureus infection significantly differed from that with both infections, respectively. Our study thus shows that patients without H. pylori infection are prone to be colonized by P. aeruginosa or S. aureus, indicating that targeted antibiotic regimens are necessary for clinically treating them.

Lactobacillus rhamnosus GG Usage in the Prevention of Gastrointestinal and Respiratory Tract Infections in Children with Gastroesophageal Reflux Disease Treated with Proton Pump Inhibitors: A Randomized Double-Blinded Placebo-Controlled Trial

PURPOSE

Proton-pump inhibitors (PPIs) are frequently used to treat gastroesophageal reflux disease (GERD) in children, but recent evidence suggests a potential association between PPI treatment and some types of infections. The aim of this study was to assess the effectiveness of Lactobacillus rhamnosus GG (LGG) for the prevention of gastrointestinal and respiratory tract infections in children with GERD treated with PPI (omeprazol).

METHODS

Children younger than 5 years with GERD were assigned by a computer-generated list to receive LGG (109 colony-forming units) or placebo, twice daily, concomitantly with PPI treatment for 4-6 weeks; they were followed up for 12 weeks after therapy. The primary outcome measures were the percentage of children with a minimum of one episode of respiratory tract infection and the percentage of children with a minimum of one episode of gastrointestinal infection during the study.

RESULTS

Of 61 randomized children, 59 patients (LGG n=30; placebo n=29, mean age 11.3 months) were analyzed. There was no significant difference found between the LGG and placebo groups, either for the proportion of children with at least one respiratory tract infection (22/30 vs. 25/29, respectively; relative risk [RR] 0.85, 95% confidence interval [CI] 0.66-1.10) or for the proportion of children with at least one gastrointestinal infection (9/30 vs. 9/29, respectively; RR 0.97, 95% CI 0.45-2.09).

CONCLUSION

LGG was not effective in the prevention of infectious complications in children with GERD receiving PPI. Caution is needed in interpreting these results, as the study was terminated early due to slow subject recruitment.

Pathophysiology of Gastroesophageal Reflux Disease in Infants and Nonpharmacologic Strategies for Symptom Management

Gastroesophageal reflux is common in young infants, particularly those born prematurely or with a history of medical complexity. The most recent clinical practice guidelines recommend the use of nonpharmacologic management strategies because of concerns about the safety of acid-reducing medications and a lack of evidence of their effectiveness. Our purpose in this article is to holistically review the pathophysiology of gastroesophageal reflux disease, identify symptom management targets, and describe nonpharmacologic strategies that nurses can implement and/or teach to parents to manage symptoms of gastroesophageal reflux. Strategies targeting stress, dysbiosis, food intolerances, feeding difficulties, and positioning are discussed. Nurses can work with families to identify factors contributing to gastroesophageal reflux disease and determine individualized strategies that can be used in lieu of, or in addition to, medication.

Small intestinal bacterial overgrowth in children with intestinal failure on home parenteral nutrition

Background and Aim

Children with intestinal failure (IF) have abnormal intestinal anatomy, secretion, or motility, which impairs homeostatic mechanisms and can lead to small intestinal bacterial overgrowth (SIBO). We sought to describe clinical features at the time of clinically suspected SIBO by experienced clinicians in children with IF on home parenteral nutrition (PN), review specific challenges of diagnostic testing in this population, and describe potential new diagnostic surrogate markers.

Methods

A descriptive single‐center retrospective chart review was performed during all episodes of clinically suspected SIBO over 33 months. Information was recorded on clinical symptoms, and diagnostic tests performed.

Results

Of all patients on home PN, 71% (12/17) had at least one episode of clinically suspected SIBO (mean 1 episode/year, range 1–7); 50% of patients had short bowel syndrome (SBS), and 50% had non‐SBS IF. The average reported symptoms per episode were 1.9 (range 1–5). Children with SBS reported fewer symptoms per episode (1.5) than children with non‐SBS IF (2.3). Diarrhea was the most commonly reported symptom, particularly in children with SBS.

Conclusions

Children with IF on home PN are a high‐risk group for SIBO. Clinical features of SIBO vary depending on the cause of IF and may mimic symptoms of the underlying condition. Diagnostic tests have innate challenges in this group, and a strong index of clinical suspicion is paramount. Further research is recommended into potential new surrogate markers (urinary metabolite screen, gastric aspirate) for this diagnostically challenging population.

Association of Proton Pump Inhibitors With Hospitalization Risk in Children With Oropharyngeal Dysphagia

Importance

Proton pump inhibitors (PPI) are commonly prescribed to children with oropharyngeal dysphagia and resultant aspiration based on the assumption that these patients are at greater risk for reflux-related lung disease. There is little data to support this approach and the potential risk for increased infections in children treated with PPI may outweigh any potential benefit.

Objective

The aim of this study was to determine if there is an association between hospitalization risk in pediatric patients with oropharyngeal dysphagia and treatment with PPI.

Design, Setting, and Participants

We performed a retrospective cohort study to compare the frequency and length of hospitalizations for children who had abnormal results on videofluoroscopic swallow studies that were performed between January 1, 2015, and December 31, 2015, and who were or were not treated with PPI, with follow-up through December 31, 2016. Records were reviewed for children who presented for care at Boston Children's Hospital, a tertiary referral center. Participants included 293 children 2 years and younger with evidence of aspiration or penetration on videofluoroscopic swallow study.

Exposures

Groups were compared based on their exposure to PPI treatment.

Main Outcomes and Measures

The primary outcomes were hospital admission rate and hospital admission nights and these were measured as incident rates. Multivariable analyses were performed to determine predictors of hospitalization risk after adjusting for comorbidities. Kaplan-Meier curves were created to determine the association of PPI prescribing with time until first hospitalization.

Results

A total of 293 patients with a mean (SD) age of 8.8 (0.4) months and a mean (SD) follow-up time of 18.15 (0.20) months were included in the analysis. Patients treated with PPI had higher admission rates (Incidence rate ratio [IRR], 1.77; 95% CI, 1.16-2.68) and admission nights (IRR, 2.51; 95% CI, 1.36-4.62) even after adjustment for comorbidities. Patients with enteral tubes who were prescribed PPIs were at the highest risk for admission (hazard ratio [HR], 2.31; 95% CI, 1.24-4.31).

Conclusions and Relevance

Children with aspiration who are treated with PPI have increased risk of hospitalization compared with untreated patients. These results support growing concern about the risks of PPI use in children.

Bacterial colonization of the stomach and duodenum in a Swedish population with and without proton pump inhibitor treatment

Background and Aim

Microbial contamination of the abdominal cavity is a serious concern during transgastric endoscopic interventions and perforations, particularly in patients who have inhibited gastric acid secretion due to treatment with proton pump inhibitors (PPIs).

The aim of this study was to investigate the gastric and duodenal bacterial flora in patients with and without PPI treatment.

Methods

Patients referred for gastroscopy, without recent antibiotic treatment, were eligible for inclusion. Use of PPIs was recorded. Samples for bacterial culturing were obtained from the antrum of the stomach and from the duodenal bulb through a gastroscope. Positive cultures were examined for bacterial types and subtypes. Biopsies were taken in the antrum for urease test to detect Helicobacter pylori.

Results

Bacterial cultures from the stomach were obtained from 103 patients, and duodenal samples were also cultured from 49 of them, for a total of 53 patients with PPI use and 50 patients without. Positive gastric cultures were found in 42 of 53 patients with PPI use and in 13 of 50 without (P < 0.0001). Duodenal cultures were positive in 20 of 24 with PPI and 8 of 25 without (P < 0.0001). The most commonly identified bacterial species were oral strains of Streptococcus, followed by Neisseria and Haemophilus influenzae. Of 103 patients, 10 had a positive urease test, indicating H. pylori infection, 1 with PPI and 9 without.

Conclusions

Bacterial growth in the stomach and duodenum is more common in patients with PPI treatment. The dominating bacterial species found in the stomach and duodenum originates from the oropharynx.

Clinical trials registry: Trial registration number 98041 in Researchweb (FoU in Sweden).

Small Intestinal Bacterial Overgrowth in Children: A State-Of-The-Art Review

Small intestinal bacterial overgrowth (SIBO) is a heterogenous and poorly understood entity characterised by an excessive growth of select microorganisms within the small intestine. This excessive bacterial biomass, in turn, disrupts host physiology in a myriad of ways, leading to gastrointestinal and non-gastrointestinal symptoms and complications. SIBO is a common cause of non-specific gastrointestinal symptoms in children, such as chronic abdominal pain, abdominal distention, diarrhoea, and flatulence, amongst others. In addition, it has recently been implicated in the pathophysiology of stunting, a disease that affects millions of children worldwide. Risk factors such as acid-suppressive therapies, alterations in gastrointestinal motility and anatomy, as well as impoverished conditions, have been shown to predispose children to SIBO. SIBO can be diagnosed via culture-dependant or culture-independent approaches. SIBO's epidemiology is limited due to the lack of uniformity and consensus of its diagnostic criteria, as well as the paucity of literature available. Antibiotics remain the first-line treatment option for SIBO, although emerging modalities such as probiotics and diet manipulation could also have a role. Herein, we present a state-of-the-art-review which aims to comprehensively outline the most current information on SIBO in children, with particular emphasis on the gut microbiota.

The Impact of the American Academy of Pediatrics Brief Resolved Unexplained Event Guidelines on Gastrointestinal Testing and Prescribing Practices

OBJECTIVES

To determine if hospitalization, testing, diagnosis, and management of suspected gastroesophageal reflux, and follow-up visits decreased since introduction of American Academy of Pediatrics guidelines for brief resolved unexplained events (BRUEs).

STUDY DESIGN

We performed a retrospective cohort study of infants with BRUE evaluated at Boston Children's Hospital in the year before and after guideline implementation to determine if practice patterns have changed. Outcomes included hospitalization rates, frequency of swallow assessments, other diagnostic testing, and reflux diagnoses, cost of care, and number of repeat visits. Groups were compared based on whether they presented before or after guideline implementation.

RESULTS

In total, 359 subjects (186 pre-, 173 post-guidelines) were identified. There were no significant differences in practice patterns or outcomes before or after guideline implementation. Subjects had mean age 2.53 ± 0.15 months, and 80% were hospitalized for 2.49 ± 0.26 days. Each subject had 2.47 diagnostic tests performed, and 89% were noncontributory. Despite only 13% having videofluoroscopic swallow study performed, 72% showed aspiration/penetration. No subject had gastroesophageal reflux testing, yet reflux was implicated as the cause for admission in 40% of subjects, resulting in increased odds of discharge on acid suppressing medications (OR 2.88, 95% CI 1.68-4.92, P = .0001). In follow-up, 28% of subjects had repeat hospitalizations or emergency department visits for persistent symptoms.

CONCLUSIONS

Infants with BRUE continue to undergo low-yield diagnostic testing and after admission remain symptomatic and frequently re-present to medical care. Swallow testing remains infrequent despite its high-yield, reflux continues to be implicated and children are still being discharged on acid suppression despite lack of efficacy.

Clinical Aspects of Thickeners for Pediatric Gastroesophageal Reflux and Oropharyngeal Dysphagia

PURPOSE OF REVIEW

The purpose of this review is to discuss current knowledge and recent findings regarding clinical aspects of thickeners for pediatric gastroesophageal reflux and oropharyngeal dysphagia. We review evidence for thickener efficacy, discuss types of thickeners, practical considerations when using various thickeners, and risks and benefits of thickener use in pediatrics.

RECENT FINDINGS

Thickeners are effective in decreasing regurgitation and improving swallowing mechanics and can often be used empirically for the treatment of infants and young children. Adverse effects have been reported, but with careful consideration of appropriate thickener types, desired thickening consistency, and follow-up in collaboration with feeding specialists, most patients have symptomatic improvements. Thickeners are typically well tolerated and with few side effects, but close follow-up is needed to make sure patients tolerate thickeners and have adequate symptom improvement.

Diagnosis and Management of Gastroesophageal Reflux Disease in Infants and Children: from Guidelines to Clinical Practice

The diagnosis and management of gastro-esophageal reflux (GER) and GER disease (GERD) in infants and children remains a challenge. Published guidelines and position papers, along with Embase, MEDLINE, and the Cochrane Database were reviewed and summarized with the intent to propose a practical approach and management of GER and GERD for healthcare providers and to standardize and improve the quality of care for infants and children. For this purpose, 2 algorithms were developed, 1 for infants <12 months of age and the other for older children. None of the signs and symptoms of GER and GERD are specific and there is no gold standard diagnostic test or tool. Nutritional management is recommended as a first-line approach in infants, while in children, a therapeutic trial with antacid medication is advised for early management. The practical recommendations from this review are intended to optimize the management of GER in infants and older children and reduce the number of investigations and inappropriate use of medication.

Choosing medications wisely: Is it time to address paediatric polypharmacy?

There is a growing focus in the medical community on de-escalating medical treatments where appropriate; however, specific efforts to reduce medication burden in patients with polypharmacy has largely been targeted toward adult populations. Polypharmacy increases the risk of adverse drug reactions in children, and that risk may be further increased by the use of off-label drugs. The paediatric prescribing community should explore pharmacovigilance strategies and deprescription initiatives that prioritize patients with polypharmacy. Currently, best practices may be extrapolated from the adult literature, including medication review algorithms and patient education tools. Enhancing access to nonpharmacological modalities to address child and youth mental health may mitigate psychotropic polypharmacy. The aim of these initiatives should be to improve patient outcomes and experiences by avoiding adverse drug events and drug-drug interactions.

Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the AGREE Conference

BACKGROUND & AIMS

Over the last decade, clinical experiences and research studies raised concerns regarding use of proton pump inhibitors (PPIs) as part of the diagnostic strategy for eosinophilic esophagitis (EoE). We aimed to clarify the use of PPIs in the evaluation and treatment of children and adults with suspected EoE to develop updated international consensus criteria for EoE diagnosis.

METHODS

A consensus conference was convened to address the issue of PPI use for esophageal eosinophilia using a process consistent with standards described in the Appraisal of Guidelines for Research and Evaluation II. Pediatric and adult physicians and researchers from gastroenterology, allergy, and pathology subspecialties representing 14 countries used online communications, teleconferences, and a face-to-face meeting to review the literature and clinical experiences.

RESULTS

Substantial evidence documented that PPIs reduce esophageal eosinophilia in children, adolescents, and adults, with several mechanisms potentially explaining the treatment effect. Based on these findings, an updated diagnostic algorithm for EoE was developed, with removal of the PPI trial requirement.

CONCLUSIONS

EoE should be diagnosed when there are symptoms of esophageal dysfunction and at least 15 eosinophils per high-power field (or approximately 60 eosinophils per mm²) on esophageal biopsy and after a comprehensive assessment of non-EoE disorders that could cause or potentially contribute to esophageal eosinophilia. The evidence suggests that PPIs are better classified as a treatment for esophageal eosinophilia that may be due to EoE than as a diagnostic criterion, and we have developed updated consensus criteria for EoE that reflect this change.

Considering gut microbiota disturbance in the management of Helicobacter pylori infection

Helicobacter pylori (Hp) infection produces drastic changes in the gastric microenvironment, which, in turn, influence the gastric microbiota composition and might be correlated with large intestinal microbiota changes. This excellent perturbing actor could trigger important modifications in the homeostatic functions exerted by gut commensals leading to a new gastrointestinal balance. At the same time, the therapeutic strategies used to eradicate Hp can modulate this physiological symbiosis, but can be also conversely affected by its properties. Area covered: The purpose of this review is to explore the reciprocal interplay between Hp infection and gut microbiota and analyze how microbial changes can influence the management of Hp eradication therapies. Expert commentary: While many studies have described Hp-dependent gut microbiota alterations, their clinical implications are only partially clear, as well as the mechanism of actions that sustain these processes. This represents a clear challenge for future research projects that will also need to understand which role is exerted by viruses, parasites, and yeasts.

Aerodigestive dysbiosis in children with chronic cough

In pediatric patients with chronic cough, respiratory culture techniques commonly yield negative results. Studies using culture-independent methods have found a high relative abundance of oral microbes in the lower airways, suggesting that the topographical continuity, and dynamics of the intraluminal contents of the aerodigestive system likely influence the lower airway microbiota. We hypothesize that in subjects with chronic cough, clinical diagnosis will correlate with distinct microbial signatures detected using culture-independent methods.

STUDY DESIGN AND METHODS

We enrolled 36 pediatric subjects with chronic cough in a cross-sectional study. Subjects were categorized into four clinical groups: asthma, bacterial bronchitis, neurologically impaired-orally fed, and neurologically impaired enterally fed. Samples from the aerodigestive tract were obtained through bronchoscopy and upper endoscopy. 16S rRNA gene sequencing compared the microbiota from bronchoalveolar lavage (BAL), tracheal, supraglottic, esophageal, gastric, and duodenal samples.

RESULTS

We observed that the lower airway microbiota of asthma subjects had higher α diversity as compared with the other groups. β diversity analysis of BAL samples revealed significant differences between the groups. Among the taxonomic differences found, most differentially enriched taxa were upper airway organisms such as Rothia, Gemellaceae (u.g. or uncharacterized genus), and Granulicatella in asthma, Prevotella in bacterial bronchitis, and Veillonella in neurologically impaired orally fed subjects. Greater dissimilarity between the upper airway and lower airway microbiota was associated with increased neutrophilic airway inflammation.

CONCLUSIONS

Distinct dysbiotic signatures can be identified in the lower airway microbiota of pediatric subjects with chronic cough that relates to the degree and type of inflammation.

Preoperative Gastroesophageal Reflux Disorder Is Associated With Increased Morbidity in Patients Undergoing Abdominal Surgery

BACKGROUND

In North America, the prevalence of gastroesophageal reflux disorder ranges from 18.1% to 27.8%. We measured the risk posed by preoperative esophageal disease for patients undergoing abdominal operations.

METHOD

American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP; 2005-2015) data were merged with institutional clinical data repository records to identify esophageal disease in surgical patients undergoing intra-abdominal procedures. Patients with esophageal disease were classified as gastroesophageal reflux disorder (GERD) or other, which included patients with esophageal stricture, spasm, ulcer, or diverticuli, achalasia, esophagitis, reflux esophagitis, Barrett's esophagus, and multiple esophageal diagnoses, excluding GERD. ACS NSQIP-targeted procedure groups included were colectomy, proctectomy, ventral hernia repair, bariatric surgery, hepatectomy, appendectomy, abdominal aortic aneurysm repair, open aortoiliac repair, hysterectomy, myomectomy, and oophorectomy. Multivariable logistic regression was used to model postoperative complication rates, adjusting for ACS NSQIP risk of morbidity, demographic factors, ACS NSQIP-targeted procedure groups, and open versus laparoscopic surgery.

RESULTS

Of 9172 intra-abdominal cases, 21.3% had preoperative esophageal disease (19.6% GERD and 1.7% other). After adjustment, patients with GERD were at higher risk for experiencing a number of complications, including all-cause 30-d complication (odds ratio [OR] = 1.21, 95% confidence interval [CI] 1.05-1.41, P = 0.044), renal complication (OR = 1.43, 95% CI 1.09-1.87, P = 0.036), wound complication (OR = 1.40, 95% CI 1.10-1.79, P = 0.028), and readmission within 30 d (OR = 1.66, 95% CI 1.35-2.04, P < 0.001).

CONCLUSIONS

Preoperative GERD is associated with increased postoperative complication rate. Surgeons should consider assessing GERD in patients undergoing abdominal operations.

The Interaction of the Gut Microbiota with the Mucus Barrier in Health and Disease in Human

Glycoproteins are major players in the mucus protective barrier in the gastrointestinal and other mucosal surfaces. In particular the mucus glycoproteins, or mucins, are responsible for the protective gel barrier. They are characterized by their high carbohydrate content, present in their variable number, tandem repeat domains. Throughout evolution the mucins have been maintained as integral components of the mucosal barrier, emphasizing their essential biological status. The glycosylation of the mucins is achieved through a series of biosynthetic pathways processes, which generate the wide range of glycans found in these molecules. Thus mucins are decorated with molecules having information in the form of a glycocode. The enteric microbiota interacts with the mucosal mucus barrier in a variety of ways in order to fulfill its many normal processes. How bacteria read the glycocode and link to normal and pathological processes is outlined in the review.

Activated gastric cancer-associated fibroblasts contribute to the malignant phenotype and 5-FU resistance via paracrine action in gastric cancer

Background

Cancer-associated fibroblasts (CAFs) play important roles in tumor progression. However, the behaviors of activated CAFs in gastric cancer remain to be determined. The aim of the present study was to investigate the correlations between activated gastric CAFs and the prognosis of patients with gastric cancer, and to determine the effects of activated CAFs on the malignant phenotype and 5-fluorouracil resistance in this cancer.

Methods

Ninety-five patients with primary gastric cancer were enrolled in this study. Activation states of gastric CAFs were evaluated by immunohistochemistry. A modified method for the primary culture of gastric CAFs was employed. Types of CAFs and activation states were identified by immunocytochemical and immunofluorescent staining. Cell co-culture and gastric CAF conditioned medium transfer models were established to investigate the paracrine effects of activated CAFs on the migration and invasion of gastric cell lines. The half maximal inhibitory concentration of 5-fluorouracil and levels of cell apoptosis were examined using cell viability assay and flow cytometry, respectively. Protein expression levels of associated molecules were measured by Western blotting.

Results

Kaplan–Meier survival curves showed that activated gastric CAFs identified via fibroblast activation protein were significantly related to poorer cumulative survival in gastric cancer patients. Five strains of CAFs were successfully cultured via the modified culture method, and three gastric CAFs strains were identified as activated gastric CAFs. The migration and invasion abilities of gastric cells were significantly enhanced in both the co-culture group and the conditioned medium group. The half maximal inhibitory concentration for 5-fluorouracil in BGC-823 cells was elevated after treatment with conditioned medium, and early apoptosis was inhibited. Additionally, an obvious elevation of epithelial–mesenchymal transition level was observed in the conditioned medium group.

Conclusions

Activated gastric CAFs correlate with a poor prognosis of cancer patients and may contribute to the malignant phenotype and the development of resistance to 5-fluorouracil via paracrine action in gastric cancer. Gastric CAFs with a specific activation state might be used as a tumor biomarker within the microenvironment for prognosis and as a new therapeutic target for chemoresistant gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0599-7) contains supplementary material, which is available to authorized users.

Detection of gastritis-associated pathogens by culturing of gastric juice and mucosa

It is well known that Helicobacter pylori (H. pylori) is not the only indigenous bacterium in the stomach, as numerous studies have revealed that the gastric microbiota contributes to the pathogenesis of gastric disease. However, the correlation between the gastric bacterial flora and gastritis is unclear. By comparing differences in viable gastric bacteria between a gastritis group and a healthy group, we examined the potential species related to chronic gastritis. We collected juice and mucosa samples from 103 consecutive patients and identified 81 species by culturing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The positive rates of Streptococcus and Neisseria were markedly higher in the gastritis group than those in the normal group, suggesting that certain bacterial species may play vital roles in the development of gastritis rather than acting as transient microbes. This finding can be applied to the diagnosis and treatment of chronic gastritis as evidence supporting non-Helicobacter pylori infection-related gastritis.

Blood biomarkers for early diagnosis of oesophageal cancer: a systematic review

BACKGROUND

Oesophageal cancer prognosis remains poor owing to the inability to detect the disease at an early stage. Nontissue (serum, urinary or salivary) biomarkers potentially offer less invasive methods to aid early detection of oesophageal cancer. We aimed to systematically review studies assessing the relationship between nontissue biomarkers and subsequent development of oesophageal cancer.

METHODS

Using terms for biomarkers and oesophageal cancer, Medline, EMBASE and Web of Science were systematically searched for longitudinal studies, published until April 2016, which assessed the association between nontissue biomarkers and subsequent oesophageal cancer risk. Random effects meta-analyses were used to calculate pooled relative risk (RR) and 95% confidence intervals (CIs), where possible.

RESULTS

A total of 39 studies were included. Lower serum pepsinogen I concentrations were associated with an increased risk of oesophageal squamous cell carcinoma (n=3 studies, pooled RR=2.20, 95% CI: 1.31-3.70). However, the association for the pepsinogen I : II ratio was not statistically significant (n=3 studies, pooled RR=2.22, 95% CI: 0.77-6.40), with a large degree of heterogeneity observed (I=68.0%). Higher serum glucose concentrations were associated with a modestly increased risk of total oesophageal cancer (n=3 studies, pooled RR=1.27, 95% CI: 1.02-1.57). No association was observed for total cholesterol and total oesophageal cancer risk (n=3 studies, pooled RR=0.95, 95% CI: 0.58-1.54). Very few studies have assessed other biomarkers for meta-analyses.

CONCLUSION

Serum pepsinogen I concentrations could aid early detection of oesophageal squamous cell carcinoma. More prospective studies are needed to determine the use of other nontissue biomarkers in the early detection of oesophageal cancer.