Abstract:

H. pylori is a common bacterium, and approximately 50 percent of the world's population has been estimated to be infected (198). Humans are the principal reservoir. The prevalence of H. pylori infection varies widely by geographic area, age, race, ethnicity, and SES. Rates appear to be higher in developing than in developed countries, with most of the infections occurring during childhood, and they seem to be decreasing with improvements in hygiene practices. H. pylori causes chronic gastritis and has been associated with several serious diseases of the gastrointestinal tract, including duodenal ulcer and gastric cancer. Since its "discovery" in 1982 by Warren and Marshall (1), H. pylori has been the topic of extensive research. A number of studies have used questionnaire components to investigate factors possibly related to the etiology of H. pylori infection. The majority of recent studies have not found tobacco use or alcohol consumption to be risk factors for H. pylori infection. Adequate nutritional status, especially frequent consumption of fruits and vegetables and of vitamin C, appears to protect against infection with H. pylori. In contrast, food prepared under less than ideal conditions or exposed to contaminated water or soil may increase the risk. Overall, inadequate sanitation practices, low social class, and crowded or high-density living conditions seem to be related to a higher prevalence of H. pylori infection. This finding suggests that poor hygiene and crowded conditions may facilitate transmission of infection among family members and is consistent with data on intrafamilial and institutional clustering of H. pylori infection. Understanding the route of H. pylori transmission is important if public health measures to prevent its spread are to be implemented. Iatrogenic transmission of H. pylori following endoscopy is the only proven mode. For the general population, the most likely mode of transmission is from person to person, by either the oral-oral route (through vomitus or possibly saliva) or perhaps the fecal-oral route. The person-to-person mode of transmission is supported by the higher incidence of infection among institutionalized children and adults and the clustering of H. pylori infection within families. Also lending support to this concept is the detection of H. pylori DNA in vomitus, saliva, dental plaque, gastric juice, and feces. Waterborne transmission, probably due to fecal contamination, may be an important source of infection, especially in parts of the world in which untreated water is common. Recent studies in the United States have linked clinical H. pylori infection with consumption of H. pylori-contaminated well water. This area of research is worthy of further investigation. Although H. pylori has been isolated in domestic cats, additional research has suggested that H. pylori is probably uncommon in domestic cats and thus is probably not a major concern for cat owners. Several studies have suggested sheep as a possible source of H. pylori transmission, a hypothesis that deserves additional investigation. The most recent reservoir suggested for H. pylori transmission is the housefly. However, evidence is lacking that H. pylori can be transmitted to humans from flies that have been in contact with H. pylori-infected feces. Nevertheless, the hypothesis is appealing since flies are known to carry many other infectious diseases. Knowledge of the epidemiology and mode of transmission of H. pylori is important to prevent its spread and may be useful in identifying high-risk populations, especially in areas that have high rates of gastric lymphoma, gastric cancer, and gastric ulcer.

Abstract:

H. pylori infection is a global public health problem associated with some gastrointestinal diseases in children, especially in developing countries, since prevalence of H. pylori is low in the developed world. Both noninvasive (stool antigen test, urea breath test, and blood test) and invasive (histology, rapid urease test, and microbiological culture) tests have been utilized to detect H. pylori infection. However, a single test is not reliable enough and does not provide accurate enough data to determine H. pylori infection among children. Risk factors of H. pylori infection in children were related to ethnicities, household properties, geographic location, living conditions, water sources, type of housing, presence/absence of sewage systems, and garbage collection within the living environment. These risk factors were usually associated with the socioeconomic status of the family. This review article aims to determine the gaps in the knowledge of the epidemiology, risk factors, and diagnostic tests of H. pylori infection among children. How to cite this article: Ozbey G, Hanafiah A. Epidemiology, Diagnosis, and Risk Factors of Helicobacter pylori Infection in Children. Euroasian J Hepato-Gastroenterol 2017;7(1):34-39.

Abstract:

Helicobacter pylori (H. pylori) is a 0.5–1 µm wide, 2–4 µm long, short helical, S-shaped Gram-negative microorganism. It is mostly found in the pyloric region of the stomach and causes chronic gastric infection. It is estimated that these bacteria infect more than half of the world’s population. The mode of transmission and infection of H. pylori is still not known exactly, but the faecal–oral and oral–oral routes via water or food consumption are thought to be a very common cause. In the last three decades, research interest has increased regarding the pathogenicity, microbial activity, genetic predisposition, and clinical treatments to understand the severity of gastric atrophy and gastric cancer caused by H. pylori. Studies have suggested a relationship between H. pylori infection and malabsorption of essential micronutrients, and noted that H. pylori infection may affect the prevalence of malnutrition in some risk groups. On the other hand, dietary factors may play a considerably important role in H. pylori infection, and it has been reported that an adequate and balanced diet, especially high fruit and vegetable consumption and low processed salty food consumption, has a protective effect against the outcomes of H. pylori infection. The present review provides an overview of all aspects of H. pylori infection, such as clinical features, treatment, and nutrition.

Abstract:

Helicobacter pylori (H. pylori) is an organism that is widespread in the human population and is sometimes responsible for some of the most common chronic clinical disorders of the upper gastrointestinal tract in humans, such as chronic-active gastritis, duodenal and gastric ulcer disease, low-grade B-cell mucosa associated lymphoid tissue lymphoma of the stomach, and gastric adenocarcinoma, which is the third leading cause of cancer death worldwide. The routes of infection have not yet been firmly established, and different routes of transmission have been suggested, although the most commonly accepted hypothesis is that infection takes place through the faecal-oral route and that contaminated water and foods might play an important role in transmission of the microorganism to humans. Furthermore, several authors have considered H. pylori to be a foodborne pathogen because of some of its microbiological and epidemiological characteristics. H. pylori has been detected in drinking water, seawater, vegetables and foods of animal origin. H. pylori survives in complex foodstuffs such as milk, vegetables and ready-to-eat foods. This review article presents an overview of the present knowledge on the microbiological aspects in terms of phenotypic characteristics and growth requirements of H. pylori, focusing on the potential role that foodstuffs and water may play in the transmission of the pathogen to humans and the methods successfully used for the detection of this microorganism in foodstuffs and water.

Abstract:

This review covers progress in identifying Helicobacter pylori-derived factors that are involved in survival and virulence of the organism and in elucidating host response pathways that can limit the infection but are also susceptible to dysregulation. Recent work has identified genes of the cytotoxin-associated gene (cag) pathogenicity island (PAI) involved in regulating signaling, interleukin-8 secretion, and phenotypic events in epithelial cells. New roles in pathogenesis have been recognized for vacuolating toxin A (VacA) and urease, H. pylori membrane and secreted factors, and host epithelial surface molecules. Molecular pathways involved in H. pylori-induced apoptosis in epithelial cells, T cells, and macrophages are being dissected. Activation of toll-like receptors and bacterial factors involved in nitric oxide (NO) and reactive oxygen species induction were also described. The ability of H. pylori to limit NO production by several mechanisms may be an important part of its ability to evade the host immune response.

Abstract:

Background Helicobacter pylori (H. pylori) is implicated for the causation of gastrointestinal tract infections including gastric cancer. Although the infection is prevalent globally, the impact is immense in countries with poor environmental and socioeconomic status including Ethiopia. Epidemiological study on the magnitude of H. pylori and possible risk factors has priceless implication. Therefore, in this study, we determined the prevalence and risk factors of H. pylori infection in the resource-limited area of northwest Ethiopia. Methods A prospective cross-sectional study was conducted on northwest Ethiopia among 201 systematically selected dyspeptic patients. Data were collected using a structured and pretested questionnaire, and stool and serum samples were collected and analyzed by SD BIOLINE H. pylori Ag and dBest H. pylori Disk tests, respectively. Chi-square test was performed to see association between variables, and binary and multinomial regression tests were performed to identify potential risk factors. P values <0.05 were taken statistically significant. Result Prevalence of H. pylori was found to be 71.1% (143/201) and 37.3% (75/201) using the dBest H. pylori Test Disk and SD BIOLINE H. pylori Ag test, respectively. H. pylori seropositivity, using dBest H. pylori Disk tests, is significantly associated in age groups <10 years (P=0.044) and married patients (P=0.016). In those patients with H. pylori (a positive result with either the Ab or Ag test), drinking water from well sources had 2.23 times risk of getting H. pylori infection (P=0.017), and drinking coffee (1.51 (0.79–2.96, P=0.025)) and chat chewing (1.78 (1.02–3.46, P=0.008) are the common risk factors. Conclusion The present study discovered considerable magnitude of H. pylori among the dyspeptic patients in the study area. H. pylori infection is frequent in individuals drinking water from well sources, and thus, poor sanitation and unhygienic water supply are contributing factors. Policies aiming at improving the socioeconomic status will reduce potential sources of infection, transmission, and ultimately the prevalence and incidence of H. pylori.

Abstract:

BACKGROUND The role of infections in pathogenesis of atherosclerosis has been a point of extensive discussion and research. Chronic infection has been proposed to account for the formation and progression of atherosclerotic plaques. Gastric mucosal damage caused by Helicobacter pylori (H. pylori) involves various bacterial and host-dependent toxic substances that have been recently associated with increased risk of coronary artery disease (CAD). AIMS This study was designed to: 1) to determine the seroprevalence of H. pylori and its cytotoxin associated gene A (CagA) in patients with and without CAD (group A), 2) to evaluate the influence of infection with H. pylori expressing CagA (Cytotoxin associated gene A--as a determinant of high virulence) on coronary arterial lumen reduction in patients after percutaneous transluminal coronary angioplasty (PTCA) with stent (group B), 3) to assess the effect of H. pylori eradication on coronary artery lumen reduction after PTCA (group C), 4) to determine the influence of the H. pylori eradication on plasma levels of cytokines, lipids and coagulation factors in the same patients before and after PTCA (group C) and 5) to analyse coronary specimens in patients with severe CAD for the presence of H. pylori originated specific DNA (Group D). PATIENTS AND METHODS Group A included 96 patients with CAD (subgroup I) and 96 patients without CAD (subgroup II). For H. pylori seroprevalence, plasma anti-H. pylori and anti-CagA IgG were examined by ELISA and Western blot. Group B included 135 patients (86 male, 49 female, mean age 67 +/- 12 years) who had underwent PTCA with stent implantation initially and recoronaro-angiography about 6 months afterwards. All patients were tested for H. pylori--specific antibodies (IgG and CagA). Patients were divided into three subgroup "a": 34 patients with H. pylori IgG and CagA seropositivity, subgroup "b": 37 patients infected with H. pylori positive and CagA negative germs and subgroup "c": 64 patients with H. pylori IgG sero-negativity serving as control group. For all patients coronary lumen loss (percentage) in the dilated segment was measured at the end of PTCA and during re-coronaro-angiography and obtained values were considered taking into account the major risk factors of CAD (hypertension, hyperlipidemia, diabetes, obesity and smoking). Group C included 40 patients with significant single-vessel CAD and H. pylori infection confirmed by 13C-urea breath test (UBT) and serologically using anti-H. pylori and anti-CagA IgG. In addition, plasma interleukin (IL)-1beta and IL-8 and tumor necrosis factor alpha (TNFalpha) levels were measured by ELISA. Plasma total triglycerides, cholesterol, low (LDL) and high density lipoproteins (HDL), homocysteine levels, as well as some clotting factors such as thromboplastin and fibrinogen levels, thrombin time and platelet count were determined. All patients of group B undergoing PTCA were divided into two matched subgroups I and II used in exploratory study; subgroup I (20 patients) received H. pylori eradication triple-therapy for one week (Clarithromycin, Amoxicillin and Omeprazole), while subgroup II (20 patients) received similarly prepared placebo for the same time period starting immediately after PTCA. Six months after PTCA, the H. pylori status was re-assessed by UBT and found to be negative in all but two patients of subgroup I subjected to H. pylori therapy. Coronary angiography and laboratory tests were repeated in both subgroups of group B included into the trial and the reduction in coronary artery lumen in these subgroups was compared to baseline after PTCA considered as 100%. Large atherosclerotic plaques from coronary endatherectomy were obtained in 46 consecutive patients (9 female, 37 male, mean age 63 +/- 9 years) during coronary bypass procedures (group D). Serum was analysed for positive IgG antibodies specific for H. pylori by enzyme-linked-immunosorbent assay (ELISA). Antibodies specific for the CagA were detected by immunoblot analysis. Polymerase chain reaction (PCR) was used to identify bacterial DNA with primers encoding for the 16 S ribosomal RNA of H. pylori. Sequence analysis of PCR-products confirmed the specificity of the gene products for H. pylori. Coronary artery biopsies from 19 autopsies from a Forensic Medicine Department without coronary atherosclerosis were examined as a control group. RESULTS The H. pylori seropositivity reached 69.79% (67 pts) of CAD (subgroup I of group A) and it was significantly higher than that in controls without CAD (subgroup II)--40.62% (39 pts), the odds ratio (OR) being 3.38 95% CI: 1.8598-6.1306 for H. pylori in CAD. CagA IgG detection was also significantly higher (58.20%) in CAD group than in controls (35.89%) giving the OR about 2.49 (95% CI: 1.1012-5.6175). Mean lumen loss in group B in H. pylori-positive subjects was 37.0% +/- 17.3%, whereas for H. pylori negative patients 29.9 +/- 13.8% were measured compared to initial values following PTCA (p = 0.0196). Even subgroup analysis and analysis regarding risk factors show significantly higher lumen loss for H. pylori-positive patients (especially CagA positive) compared to H. pylori negative patients. Mean coronary artery lumen reduction in patients undergoing PTCA + H. pylori eradication therapy (subgroup I of group C) was found to be significantly (P < 0.05) smaller compared to PTCA + placebo-treated subgroup II (22% vs 41%). The plasma cytokines such as TNFalpha, IL-1beta and IL-8 were significantly lower after the H. pylori-eradication in PTCA patients, while changes in plasma lipids, homocysteine and clotting factors were not significantly affected by H. pylori eradication. In group D thirty two patients (69.5%) were H. pylori-seropositive, 14 patients out of 32 H. pylori-positive were CagA positive. Eighteen of these patients showed positive results for H. pylori DNA, whereas 4 patients of the seronegative group also showed positive DNA results, but all 4 had undergone eradication therapy within the past two years. A total of 22 patients (47.8%) of the CAD group and none of the 19 controls revealed positive DNA assessed by PCR. Out of 14 anti-Cag A positive patients 11 showed positive detection of H. pylori DNA (p = 0.015) CONCLUSIONS 1) There is a significant link between CAD and infection with H. pylori, especially expressing CagA proteins; 2) Patients infected with CagA-positive H. pylori show significantly greater coronary artery lumen loss and arterial re-stenosis after PTCA with stent implantation; 3) H. pylori eradication significantly attenuates the reduction in coronary artery lumen in CAD patients after PTCA possibly due to the elimination of chronic inflammation and the decline in proinflammatory cytokine release and 4) The identification of DNA in atherosclerotic plaques of patients with severe CAD supports the hypothesis that infection with H. pylori (especially CagA positive) may influence the development of atherosclerosis.

Abstract:

Idiopathic thrombocytopenic purpura (ITP), an autoimmune disease caused by sensitization of platelets by autoantibodies leading to platelet destruction, has been associated with some infectious agents, including Helicobacter pylori. The study by Suzuki et al., published in this issue, provides further evidence of the role of H. pylori infection in the pathogenesis of ITP, as confirmed by the increase in the platelet count in patients with ITP, following H. pylori eradication. Interestingly, H. pylori infection has also been shown to play a role in other diseases in which autoimmune mechanisms may be predominant, such as acne rosacea, idiopathic chronic urticaria, and atherosclerosis. While H. pylori eradication is usually recommended in patients with gastric diseases, there are no specific indications for extraalimentary diseases. In the light of the recent findings, a revision of the current guidelines for the management of H. pylori infection may be needed.

Abstract:

Helicobacter pylori infection and transmission routes Helicobacter pylori is a gram-negative microaerophilic bacterium. The infection of H. pylori can increase the risk of gastric cancer which is the second leading cause of cancer death worldwide [1]. The World Health Organization’s International Agency for Research on Cancer (IARC) has classified H. pylori as a type I (definite) carcinogen since 1994. H. pylori infection is a global health problem. In developed countries, its infection rate is 20% to 50%, while in developing countries, the infection rate of middle-aged people has reached 80% [2]. The fecal– oral and the oral–oral routes are considered as the main transmission routes of H. pylori [3]. Nevertheless, only H. pylori genes have been detected in saliva and dental plaques, but culturable H. pylori has not been isolated yet in large quantities [4], indicating that there may be some new strategies of H. pylori to implement its transmission through oral cavity. Candida albicans, a dimorphic fungus, is one of the most common fungi in the human body [5]. It was noteworthy that C. albicans and H. pylori were abundant in certain human niches, such as the root canal necrotic pulp, stomach, duodenum, and vagina [6], suggesting that C. albicans may interact with H. pylori to promote the growth, spread, and infection of H. pylori in some nonadaptive condition, such as the oral cavity and vagina.

Abstract:

Objective To ascertain the prevalence of Helicobacter pylori infection in Germany and to identify risk factors associated with H. pylori seroconversion. Methods Two hundred and sixty blood donors (169 men, 91 women; median age 29 years, range 18–61 years, 92% with German parents, all white) were studied. None had previously been treated for H. pylori infection. Their serum samples were analysed for H. pylori immunoglobulin (lg) G antibodies with a validated enzyme-linked immunosorbent assay (ELISA). All subjects completed a complex questionnaire under supervision. Special attention was paid to their present and childhood (at the age of 8 years) living conditions. To identify independent risk factors for seropositivity, a multivariate, stepwise forward, unconditional, logistic regression analysis was performed. Results In total, 102 participants (39.2%) were seropositive for H. pylori. Seroprevalence increased significantly with age (21.1% aged 21 or younger compared with 60.0% over 51 years of age). According to the multivariate analysis of the unclassified data [odds ratio (95% confidence interval)], variables such as age [1.04 (1.01–1.07) per year], persons per room in household in childhood [2.14 (1.07–4.26)] and number of children (<8 years) in household at present [1.79 (1.01–3.16) per child] were significantly and independently associated with H. pylori seroprevalence. Conclusion Crowded living conditions in childhood affect current H. pylori status. In addition, the number of children in the present household increases the risk of infection for the adult family members. This suggests that children are an additional source of infection, probably due to close and frequent physical contact outside the immediate family.

Abstract:

Helicobacter pylori (H. pylori) infection is one of the most common infection in humans, affecting more than half of the population. The prevalence of the infection varies widely in rural developing areas (more than 80%) compared to urban developed ones (less than 40%), as a consequence of different socioeconomic and hygienic conditions. H. pylori infection is usually acquired during childhood; infected people usually remain asymptomatic, but about 30% of individuals may develop mild to severe upper gastrointestinal diseases such as gastritis, peptic ulcer, gastric cancer or MALT lymphoma. The transmission route is not clear yet; the person-to-person transmission, especially within the same family appears to be prevalent, but also environmental contamination is possible. The eradication without a specific therapeutic regimen is very unlikely and the reinfection rate after an effective eradication therapy is quite rare. The reinfection rate will increase if there are family members affected. (www.actabiomedica.it)

Abstract:

Both Helicobacter pylori (H. pylori) infection and liver diseases, including nonalcoholic fatty liver disease (NAFLD), viral hepatitis, and hepatocellular carcinoma (HCC), have high prevalences worldwide, and the relationship between H. pylori infection and liver disease has been discussed for many years. Although positive correlations between H. pylori and NAFLD have been identified in some clinical and experimental studies, negative correlations have also been obtained in high-quality clinical studies. Associations between H. pylori and the pathogenesis of chronic viral hepatitis, mainly disease progression with fibrosis, have also been suggested in some clinical studies. Concerning HCC, a possible role for H. pylori in hepatocarcinogenesis has been identified since H. pylori genes have frequently been detected in resected HCC specimens. However, no study has revealed the direct involvement of H. pylori in promoting the development of HCC. Although findings regarding the correlations between H. pylori and liver disease pathogenesis have been accumulating, the existing data do not completely lead to an unequivocal conclusion. Further high-quality clinical and experimental analyses are necessary to evaluate the efficacy of H. pylori eradication in ameliorating the histopathological changes observed in each liver disease.

Abstract:

Helicobacter pylori (H.pylori) is a gram-negative bacterium that has infected more than half of the world's population. This pathogen colonizes the human gastric mucosa and is usually acquired during childhood. It is an important cause of peptic ulcers, chronic gastritis and stomach cancer. Among the risk factors for acquisition of H. pylori infection, poor socioeconomic status, poor sanitization and hygiene practices, and contaminated food and water, are the most significant ones. The main route of H. pylori transmission is still unknown. Studies show that H.pylori bacteria can spread directly from one person to the other, or indirectly from an infected person to the environment. Person to person transmission is divided into fecal-oral, gastric-oral, oral-oral, sexual routes. Presently, interpersonal pathways are more acceptable than environmental exposure routes. Literatures indicate the presence and survival of H. pylori in food samples, such as milk, vegetables and meat, and suggest these foods may play an important role in the environmental transmission of this pathogen. In addition, other studies report the presence of H. pylori in the gastric tissue of some animals (e.g. sheep and cow) and therefore, it is likely they participate in the food chain transmission as reservoirs besides human. Although there are findings which indicate the probable role of food products in the environmental transmission of H. pylori, there is still not enough direct evidence to confirm this and more studies are needed. However, attention to food contamination sources (unhygienic water) and controlling them may prevent transmission of pathogens associated with health.

Abstract:

BACKGROUND Gastric cancer is the second leading cause of cancer-related deaths worldwide and infection with H. pylori is considered essential for its development. Helicobacter pylori infects more than 50% of the world's population with higher prevalence in developing countries than developed countries. The prevalence of H. pylori varies in different societies and geographical locations. The objectives of this study were to estimate the seroprevalence and determine the risk factors of H. pylori infection in dyspeptic patents in Ethiopia. MATERIALS AND METHODS A cross-sectional study involving 209 dyspeptic patients was carried out from February 15 to April 30, 2013. Five to ten ml venous blood was collected from each dyspeptic patient and analyzed for detection of Helicobacter pylori immunoglobulin (IgG). The socio-demographic characteristic, hygienic practices, alcohol consumption, sources of drinking water and types of latrine were also obtained with a pre-tested questionnaire. RESULTS The overall seroprevalence of Helicobacter pylori was 72.2%. There was statistically significant difference in the prevalence of H. pylori among age groups (p=0.02). Seroprevalence of H. pylori was higher in those patients who used unprotected surface water (76.4%) than those with access to piped tap water (65.9%). There was also statistically significant differences in prevalence of H. pylori with the habit of hand washing before meal (p=0.01) and alcohol consumption (p=0.001). CONCLUSIONS The prevalence of H. pylori was high in the study area and increased with age of dyspeptic patients. Alcohol consumption and the type of drinking water are risk factors that have associations with the prevalence of H. pylori. Molecular epidemiological techniques can show a true picture of H. pylori and improvement in the drinking water quality is recommended.