Identificación y evaluación de lesiones gástricas premalignas asociadas a la infección por Helicobacter pylori / Identification and evaluation of premalignant gastric lesions associated with Helicobacter pylori infection

Introducción: La infección por Helicobacter pylori es la causa principal de enfermedades gastroduodenales (gastritis crónica, úlceras pépticas y cáncer gástrico). En Guatemala existen pocos estudios sobre la prevalencia de H. pylori y su relación con enfermedades gastrointestinales, particularmente con cáncer. Objetivos: Identificar la presencia de lesiones premalignas (atrofia gástrica, metaplasia intestinal y displasia) y su relación con la infección por H. pylori en pacientes de consulta externa en unidades de gastroenterología de dos hospitales nacionales de la ciudad de Guatemala. Métodos: El diagnóstico histopatológico y bacteriológico se realizó por medio de las tinciones de H & E y Giemsa, cultivo e identificación bioquímica, detección de anticuerpos específicos mediante la prueba ELISA, diagnóstico molecular por la amplificación del gen glmM y genotipificación por PCR para identificar los genes VacA y CagA. Se analizaron datos clínico-epidemiológicos de los pacientes, la prevalencia de la infección por H. pylori y la genotipificación de la bacteria. Resultados: En 293 de los pacientes estudiados (83 por ciento) se encontró algún tipo de lesión premaligna; las más frecuentes fueron la atrofia gástrica (70 por ciento), metaplasia intestinal (11 por ciento) y displasia gástrica (2 por ciento). El 17 por ciento de los pacientes no presentó lesiones premalignas. Se halló una prevalencia de infección por H. pylori del 58 por ciento, y el gen cagA se detectó en 118 (57 por ciento) de los pacientes infectados. Conclusiones: La mayoría de los pacientes presentó atrofia gástrica (70 por ciento) y el 43,5 por ciento estaba infectado por H. pylori, principalmente con cepas CagA positivo. Este hecho confirma la importancia del estudio de H. pylori y su relación con cáncer gástrico(AU)

Introduction: Helicobacter pylori infection is the main cause of gastroduodenal diseases (chronic gastritis, peptic ulcer and gastric cancer). In Guatemala few studies have been carried out on the prevalence of H. pylori and its relationship with gastrointestinal diseases, particularly with cancer. Objective: To identify the presence of premalignant lesions (gastric atrophy, intestinal metaplasia and dysplasia) and their relationship with H. pylori infection in outpatients in gastroenterology units in two national hospitals in Guatemala City. Methods: Histopathological and bacteriological diagnostic testings were performed by H & E and Giemsa stain, culture and biochemical identification, detection of specific antibodies by ELISA, molecular diagnosis by glmM gene amplification, and genotypification by PCR to identify vacA and cagA genes. Clinical and epidemiological data from patients, prevalence of H. pylori infection, and bacterium genotypification were analyzed. Results: Among the studied patients, 293 (83 percent) presented some type of premalignant lesion. The most prevalent were gastric atrophy (70 percent), intestinal metaplasia (11 percent), and gastric dysplasia (2 percent). Seventeen percent of the patients did not have any premalignant lesions. The prevalence of H. pylori infection was 58 percent, and cagA gene was identified in 118 (57 percent) of the infected patients. Conclusions: The majority of the patients presented gastric atrophy (70 percent), and 43.5 percent were infected by H. pylori, mainly with positive cagA strains. This finding confirms the importance of studying H. pylori and its relationship with gastric cancer(AU)

A single early-in-life antibiotic course increases susceptibility to DSS-induced colitis.

BACKGROUND: There is increasing evidence that the intestinal microbiota plays a crucial role in the maturation of the immune system and the prevention of diseases during childhood. Early-life short-course antibiotic use may affect the progression of subsequent disease conditions by changing both host microbiota and immunologic development. Epidemiologic studies provide evidence that early-life antibiotic exposures predispose to inflammatory bowel disease (IBD). METHODS: By using a murine model of dextran sodium sulfate (DSS)-induced colitis, we evaluated the effect on disease outcomes of early-life pulsed antibiotic treatment (PAT) using tylosin, a macrolide and amoxicillin, a beta-lactam. We evaluated microbiota effects at the 16S rRNA gene level, and intestinal T cells by flow cytometry. Antibiotic-perturbed or control microbiota were transferred to pups that then were challenged with DSS. RESULTS: A single PAT course early-in-life exacerbated later DSS-induced colitis by both perturbing the microbial community and altering mucosal immune cell composition. By conventionalizing germ-free mice with either antibiotic-perturbed or control microbiota obtained 40 days after the challenge ended, we showed the transferrable and direct effect of the still-perturbed microbiota on colitis severity in the DSS model. CONCLUSIONS: The findings in this experimental model provide evidence that early-life microbiota perturbation may increase risk of colitis later in life.

Ongoing Challenges Faced in the Global Control of COVID-19 Pandemic.

The recent pandemic caused by SARS-CoV-2 has now spread worldwide and caused more than 51,000 deaths, by April 2nd 2020. As predicted, there are several obstacles for medical and governmental authorities to efficiently manage this respiratory illness. In spite of appropriated supplies, most hospitals are suffering from a scarcity of free beds, protective masks, sanitizing liquids and even ECMO machines for patients with severe cases. Defeating this pandemic is impossible without united and coordinated international attempts shaped by all countries of the world. We believe that an international scaled-determination is required to diminish the complex impacts of pandemic. The most important priorities are supposed to be i) The development of potential vaccine candidates to provide protection and interrupt the transmission of SARS-CoV-2, ii) To ensure enough supplies for hospitals and their homogeneous distribution among the countries with the worst number of severe cases, iii) There is a need for more studies to identify potential treatments that are effective for the control of this viral infection and iv) It is imperative to provide easy access to diagnostic kits for all countries affected by this pandemic. In the light of these suggestions, it would be recommendable to at least temporarily abandon the political checkouts in both national and international levels; therefore, all partners will be potentially able to efficiently enforce their strategies for the elimination of this unique threat to the human populations.

Long-Term Effects of Early-Life Antibiotic Exposure on Resistance to Subsequent Bacterial Infection.

Early-life antibiotic exposure may provoke long-lasting microbiota perturbation. Since a healthy gut microbiota confers resistance to enteric pathogens, we hypothesized that early-life antibiotic exposure would worsen the effects of a bacterial infection encountered as an adult. To test this hypothesis, C57BL/6 mice received a 5-day course of tylosin (macrolide), amoxicillin (ß-lactam), or neither (control) early in life and were challenged with Citrobacter rodentium up to 80 days thereafter. The early-life antibiotic course led to persistent alterations in the intestinal microbiota and even with pathogen challenge 80 days later worsened the subsequent colitis. Compared to exposure to amoxicillin, exposure to tylosin led to greater disease severity and microbiota perturbation. Transferring the antibiotic-perturbed microbiota to germfree animals led to worsened colitis, indicating that the perturbed microbiota was sufficient for the increased disease susceptibility. These experiments highlight the long-term effects of early-life antibiotic exposure on susceptibility to acquired pathogens.IMPORTANCE The gastrointestinal microbiota protects hosts from enteric infections; while antibiotics, by altering the microbiota, may diminish this protection. We show that after early-life exposure to antibiotics host susceptibility to enhanced Citrobacter rodentium-induced colitis is persistent and that this enhanced disease susceptibility is transferable by the antibiotic-altered microbiota. These results strongly suggest that early-life antibiotics have long-term consequences on the gut microbiota and enteropathogen infection susceptibility.

Is There a Role for the Non-Helicobacter pylori Bacteria in the Risk of Developing Gastric Cancer?

Helicobacter pylori is the most abundant bacterium in the gastric epithelium, and its presence has been associated with the risk of developing gastric cancer. As of 15 years ago, no other bacteria were associated with gastric epithelial colonization; but thanks to new methodologies, many other non-H. pylori bacteria have been identified. It is possible that non-H. pylori may have a significant role in the development of gastric cancer. Here, we discuss the specific role of H. pylori as a potential trigger for events that may be conducive to gastric cancer, and consider whether or not the rest of the gastric microbiota represent an additional risk in the development of this disease.

Helicobacter pylori the Latent Human Pathogen or an Ancestral Commensal Organism.

We dedicated this review to discuss Helicobacter pylori as one of the latest identified bacterial pathogens in humans and whether its role is mainly as a pathogen or a commensal. Diseases associated with this bacterium were highly prevalent during the 19th century and gradually have declined. Most diseases associated with H. pylori occurred in individuals older than 40 years of age. However, acquisition of H. pylori occurs mainly in young children inside the family setting. Prevalence and incidence of H. pylori has had a dramatic change in the last part of the 20th century and beginning of the 21th century. In developed countries there is a clear interruption of transmission and the lowest prevalence is observed in children younger than 10 years in these countries. A similar decline is observed but not at the same level in developing countries. Here we discuss the impact of the presence or absence of H. pylori in the health status of humans. We also discuss whether it is necessary or not to establish H. pylori eradication programs on light of the current decline in H. pylori prevalence.

When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children.

Helicobacter pylori colonization is prevalent throughout the world, and is predominantly acquired during childhood. In developing countries, >70% of adult populations are colonized with H. pylori and >50% of children become colonized before the age of 10 years. However, the exact timing of acquisition is unknown. We assessed detection of H. pylori acquisition among a birth cohort of 105 children in Mirzapur, Bangladesh. Blood samples collected at time 0 (cord blood), and at 6, 12, 18, and 24 months of life were examined for the presence of IgG and IgA antibodies to whole cell H. pylori antigen and for IgG antibodies to the CagA antigen using specific ELISAs and immunoblotting. Breast milk samples were analyzed for H. pylori-specific IgA antibodies. Cord blood was used to establish maternal colonization status. H. pylori seroprevalence in the mothers was 92.8%. At the end of the two-year follow-up period, 50 (47.6%) of the 105 children were positive for H. pylori in more than one assay. Among the colonized children, CagA prevalence was 78.0%. A total of 58 children seroconverted: 50 children showed persistent colonization and 8 (7.6%) children showed transient seroconversion, but immunoblot analysis suggested that the transient seroconversion observed by ELISA may represent falsely positive results. Acquisition of H. pylori was not influenced by the mother H. pylori status in serum or breastmilk. In this population with high H. pylori prevalence, we confirmed that H. pylori in developing countries is detectable mainly after the first year of life.

Gut Microbiome and Antibiotics.

Despite that the human gastrointestinal tract is the most populated ecological niche by bacteria in the human body, much is still unknown about its characteristics. This site is highly susceptible to the effects of many external factors that may affect in the quality and the quantity of the microbiome. Specific factors such as diet, personal hygiene, pharmacological drugs and the use of antibiotics can produce a significant impact on the gut microbiota. The effect of these factors is more relevant early in life, when the gut microbiota has not yet fully established. In this review, we discussed the effect of type and doses of the antibiotics on the gut microbiota and what the major consequences in the use and abuse of these antimicrobial agents.

A single early-in-life macrolide course has lasting effects on murine microbial network topology and immunity.

Broad-spectrum antibiotics are frequently prescribed to children. Early childhood represents a dynamic period for the intestinal microbial ecosystem, which is readily shaped by environmental cues; antibiotic-induced disruption of this sensitive community may have long-lasting host consequences. Here we demonstrate that a single pulsed macrolide antibiotic treatment (PAT) course early in life is sufficient to lead to durable alterations to the murine intestinal microbiota, ileal gene expression, specific intestinal T-cell populations, and secretory IgA expression. A PAT-perturbed microbial community is necessary for host effects and sufficient to transfer delayed secretory IgA expression. Additionally, early-life antibiotic exposure has lasting and transferable effects on microbial community network topology. Our results indicate that a single early-life macrolide course can alter the microbiota and modulate host immune phenotypes that persist long after exposure has ceased.High or multiple doses of macrolide antibiotics, when given early in life, can perturb the metabolic and immunological development of lab mice. Here, Ruiz et al. show that even a single macrolide course, given early in life, leads to long-lasting changes in the gut microbiota and immune system of mice.

Global Fecal and Plasma Metabolic Dynamics Related to Helicobacter pylori Eradication.

Background:Helicobacter pylori colonizes the gastric mucosa of more than half of the world's population. There is increasing evidence H. pylori protects against the development of obesity and childhood asthma/allergies in which the development of these diseases coincide with transient dysbiosis. However, the mechanism underlying the association of H. pylori eradication with human metabolic and immunological disorders is not well-established. In this study, we aimed to investigate the local and systemic effects of H. pylori eradication through untargeted fecal lipidomics and plasma metabolomics approaches by liquid chromatography mass spectrometry (LC-MS). Results: Our study revealed that eradication of H. pylori eradication (i.e., loss of H. pylori and/or H. pylori eradication therapy) changed many global metabolite/lipid features, with the majority being down-regulated. Our findings primarily show that H. pylori eradication affects the host energy and lipid metabolism which may eventually lead to the development of metabolic disorders. Conclusion: These predictive metabolic signatures of metabolic and immunological disorders following H. pylori eradication can provide insights into dynamic local and systemic metabolism related to H. pylori eradication in modulating human health.

Rapid identification of Helicobacter pylori and assessment of clarithromycin susceptibility from clinical specimens using FISH.

Helicobacter pylori remains one of the most common bacterial infections worldwide. Clarithromycin resistance is the most important cause of H. pylori eradication failures. Effective antibiotic therapies in H. pylori infection must be rapidly adapted to local resistance patterns. We investigated the prevalence of clarithromycin resistance due to mutations in positions 2142 and 2143 of 23SrRNA gene of H. pylori by fluorescence in situ hybridisation (FISH), and compared with culture and antimicrobial susceptibility testing in 234 adult patients with dyspepsia who were enrolled. Antrum and corpus biopsy specimens were obtained for rapid urease test, histopathology and culture. Epsilometer test was used to assess clarithromycin susceptibility. H. pylori presence and clarithromycin susceptibility were determined by FISH in paraffin-embedded biopsy specimens. We found that 164 (70.1%) patients were positive for H. pylori based on clinical criteria, 114 (69.5% CI 62.5-76.6%) were culture positive, and 137 (83.5% CI 77.8-89.2%) were FISH positive. Thus the sensitivity of FISH was significantly superior to that of culture. However specificity was not significantly different (91.4 versus 100.0%, respectively). The resistance rate to clarithromycin for both antrum and corpus was detected in H. pylori-positive patients; 20.2% by FISH and 28.0% by E-test.The concordance between E-test and FISH was only 89.5% due to the presence of point mutations different from A2143G, A2142G or A2142C. We conclude that FISH is significantly more sensitive than culture and the E-test for the detection of H. pylori and for rapid determinination of claritromycin susceptibility. The superior hybridisation efficiency of FISH is becoming an emerging molecular tool as a reliable, rapid and sensitive method for the detection and visualisation of H. pylori, especially when the management of H. pylori eradication therapy is necessary. This is particularly important for the treatment of patients with H. pylori eradication failure.

Description of two novel members of the family Erysipelotrichaceae: Ileibacterium valens gen. nov., sp. nov. and Dubosiella newyorkensis, gen. nov., sp. nov., from the murine intestine, and emendation to the description of Faecalibaculum rodentium.

To better characterize murine intestinal microbiota, a large number (187) of Gram-positive-staining, rod- and coccoid-shaped, and facultatively or strictly anaerobic bacteria were isolated from small and large intestinal contents from mice. Based on 16S rRNA gene sequencing, a total 115 isolates formed three phylogenetically distinct clusters located within the family Erysipelotrichaceae. Group 1, as represented by strain NYU-BL-A3T, was most closely related to Allobaculum stercoricanis, with 16S rRNA gene sequence similarity values of 87.7 %. A second group, represented by NYU-BL-A4T, was most closely related to Faecalibaculum rodentium, with 86.6 % 16S rRNA gene sequence similarity. A third group had a nearly identical 16S rRNA gene sequence (99.9 %) compared with the recently described Faecalibaculum rodentium, also recovered from a laboratory mouse; however, this strain had a few differences in biochemical characteristics, which are detailed in an emended description. The predominant (>10 %) cellular fatty acids of strain NYU-BL-A3T were C16 : 0 and C18 : 0, and those of strain NYU-BL-A4T were C10 : 0, C16 : 0, C18 : 0 and C18 : 1ω9c. The two groups could also be distinguished by multiple biochemical reactions, with the group represented by NYU-BL-A4T being considerably more active. Based on phylogenetic, biochemical and chemotaxonomic criteria, two novel genera are proposed, Ileibacterium valens gen. nov., sp. nov. with NYU-BL-A3T (=ATCC TSD-63T=DSM 103668T) as the type strain and Dubosiella newyorkensis gen. nov., sp. nov. with NYU-BL-A4T (=ATCC TSD-64T=DSM 103457T) as the type strain.

Helicobacter pylori colonization and pregnancies complicated by preeclampsia, spontaneous prematurity, and small for gestational age birth.

BACKGROUND: Preeclampsia (PE), small for gestational age (SGA), and spontaneous preterm birth (PTB) each may be complications of impaired placental function in pregnancy. Although their exact pathogenesis is still unknown, certain infectious agents seem to play a role. Helicobacter pylori (H. pylori) colonization has been associated with increased risk for PE. Our aim was to assess the association between H. pylori colonization and PE, SGA, and PTB. MATERIAL AND METHODS: We measured IgG anti-H. pylori and CagA antibodies in serum of pregnant women (median 20.5 weeks, range 16.5-29.4) who participated in a population-based prospective cohort study. Delivery and medical records were assessed. Information on demographics, education, and maternal risk factors was collected by questionnaire. We used multivariate logistic regression analyses to assess associations between H. pylori colonization and PE, SGA, and PTB. RESULTS: In total, 6348 pregnant women were assessed. H. pylori positivity was found in 2915 (46%) women, of whom 1023 (35%) also were CagA-positive. Pregnancy was complicated by PE, SGA, or PTB in 927 (15%) women. H. pylori colonization was associated with PE (aOR 1.51; 95%CI 1.03-2.25). Differentiation according to CagA status revealed the same risk. H. pylori was positively related with SGA, mainly explained by CagA-positive strains (aOR 1.34; 1.04-1.71). No association was observed between H. pylori and PTB. CONCLUSIONS: Our data suggest that H. pylori colonization may be a risk factor for PE and SGA. If these associations are confirmed by future studies and shown to be causal, H. pylori eradication may reduce related perinatal morbidity and mortality.

Effect of antibiotic pre-treatment and pathogen challenge on the intestinal microbiota in mice.

BACKGROUND: More than 50 years after the discovery of antibiotics, bacterial infections have decreased substantially; however, antibiotics also may have negative effects such as increasing susceptibility to pathogens. An intact microbiome is an important line of defense against pathogens. We sought to determine the effect of orally administered antibiotics both on susceptibility to pathogens and on impact to the microbiome. We studied Campylobacter jejuni, one of the most common causes of human diarrhea, and Acinetobacter baumannii, which causes wound infections. We examined the effects of antibiotic treatment on the susceptibility of mice to those pathogens as well as their influence on the mouse gut microbiome. RESULTS: In C57/BL6 mice models, we explored the effects of pathogen challenge, and antibiotic treatment on the intestinal microbiota. Mice were treated with either ciprofloxacin, penicillin, or water (control) for a 5-day period followed by a 5-day washout period prior to oral challenge with C. jejuni or A. baumannii to assess antibiotic effects on colonization susceptibility. Mice were successfully colonized with C. jejuni more than 118 days, but only transiently with A. baumannii. These challenges did not lead to any major effects on the composition of the gut microbiota. Although antibiotic pre-treatment did not modify pathogen colonization, it affected richness and community structure of the gut microbiome. However, the antibiotic dysbiosis was significantly reduced by pathogen challenge. CONCLUSIONS: We conclude that despite gut microbiota disturbance, susceptibility to gut colonization by these pathogens was unchanged. The major gut microbiome disturbance produced by antibiotic treatment may be reduced by colonization with specific microbial taxa.

Systematic analysis of phosphotyrosine antibodies recognizing single phosphorylated EPIYA-motifs in CagA of East Asian-type Helicobacter pylori strains.

BACKGROUND: Highly virulent strains of the gastric pathogen Helicobacter pylori encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation by members of the oncogenic c-Src and c-Abl host kinases at EPIYA-sequence motifs A, B and D in East Asian-type strains. These phosphorylated EPIYA-motifs serve as recognition sites for various SH2-domains containing human proteins, mediating interactions of CagA with host signaling factors to manipulate signal transduction pathways. Recognition of phospho-CagA is mainly based on the use of commercial pan-phosphotyrosine antibodies that were originally designed to detect phosphotyrosines in mammalian proteins. Specific anti-phospho-EPIYA antibodies for each of the three sites in CagA are not forthcoming. RESULTS: This study was designed to systematically analyze the detection preferences of each phosphorylated East Asian CagA EPIYA-motif by pan-phosphotyrosine antibodies and to determine a minimal recognition sequence. We synthesized phospho- and non-phosphopeptides derived from each predominant EPIYA-site, and determined the recognition patterns by seven different pan-phosphotyrosine antibodies using Western blotting, and also investigated representative East Asian H. pylori isolates during infection. The results indicate that a total of only 9-11 amino acids containing the phosphorylated East Asian EPIYA-types are required and sufficient to detect the phosphopeptides with high specificity. However, the sequence recognition by the different antibodies was found to bear high variability. From the seven antibodies used, only four recognized all three phosphorylated EPIYA-motifs A, B and D similarly well. Two of the phosphotyrosine antibodies preferentially bound primarily to the phosphorylated motif A and D, while the seventh antibody failed to react with any of the phosphorylated EPIYA-motifs. Control experiments confirmed that none of the antibodies reacted with non-phospho-CagA peptides and in accordance were able to recognize phosphotyrosine proteins in human cells. CONCLUSIONS: The results of this study disclose the various binding preferences of commercial anti-phosphotyrosine antibodies for phospho-EPIYA-motifs, and are valuable in the application for further characterization of CagA phosphorylation events during infection with H. pylori and risk prediction for gastric disease development.

Antibiotics, birth mode, and diet shape microbiome maturation during early life.

Early childhood is a critical stage for the foundation and development of both the microbiome and host. Early-life antibiotic exposures, cesarean section, and formula feeding could disrupt microbiome establishment and adversely affect health later in life. We profiled microbial development during the first 2 years of life in a cohort of 43 U.S. infants and identified multiple disturbances associated with antibiotic exposures, cesarean section, and formula feeding. These exposures contributed to altered establishment of maternal bacteria, delayed microbiome development, and altered α-diversity. These findings illustrate the complexity of early-life microbiome development and its sensitivity to perturbation.