Epidemiology of Helicobacter pylori infection

Lower Incidence of Hepatobiliary Cancer in Helicobacter pylori-Infected Persons: A Cohort Study of 53.633 Persons

BACKGROUND AND AIMS

Helicobacter pylori (HP) is known to be involved in intestinal carcinogenesis. As regards hepatobiliary cancers, there are few and inconsistent reports. We investigated HP infection and its association with the incidence of hepatobiliary cancers in a large cohort study. The cohort's appropriateness for the purpose was gauged by its ability to identify the established risk relation to gastric cancer.

METHODS

This historical study was performed in the Central Denmark Region. Patients were included from primary healthcare after being tested for HP infection with a urea breath test. Patients' diagnoses, age, gender, and country of birth were obtained from Danish national administrative registries. Cox regression was used to compare incidences of hepatobiliary and gastric cancer between HP-positive and HP-negative persons, adjusting for confounding variables.

RESULTS

A total of 53,633 persons were included and 10,553 were tested HP-positive. They were followed for a median of 4.6 years (total 250,515 person-years). We found 64 hepatobiliary cancers, with a markedly lower incidence in HP-positive persons; HR = 0.27 (95% CI 0.11-0.68). A higher incidence of gastric cancer in HP-positive persons was confirmed (HR = 1.99 (95% CI 1.35-2.94)).

CONCLUSION

The incidence of hepatobiliary cancers was remarkably lower in HP-infected persons after adjusting for age, gender, cirrhosis, alcohol-related diagnoses, chronic viral hepatitis, and country of origin. We found no methodological cause for this unexpected finding, and the pathogenic links between the infection and cancer remain to be identified. Our results must be confirmed in a similar cohort.

Three-Decade Failure to the Eradication of Refractory Helicobacter pylori Infection and Recent Efforts to Eradicate the Infection

BACKGROUND

Helicobacter pylori causes dangerous and deadly diseases such as gastric cancer and duodenal ulcers. Eradication and treatment of this bacterium are very important due to the deadly diseases caused by H. pylori and the high cost of treatment for countries.

METHODS

Thus, we present a complete list of the most important causes of failure in the treatment and eradication of H. pylori, and address new therapeutic methods that may be effective in controlling this bacterium in the future.

RESULTS

Many efforts have been made to control and eradicate this bacterium over the years, but no success has been achieved since its eradication is a complex process affected by the bacterial properties and host factors. Previous studies have shown that various factors are involved in the failure to eradicate H. pylori, such as new genotypes of the bacterium with higher pathogenicity, inappropriate patient cooperation, mutations, biofilm formation and dormant forms that cause antibiotic resistance, acidic stomach pH, high bacterial load, smoking, immunosuppressive features and intracellular occurrence of H. pylori. On the other hand, recent studies reported that the use of probiotics, nanoparticles, antimicrobial peptides, natural product and vaccines can be helpful in the treatment and eradication of H. pylori infections.

CONCLUSION

Eradication of H. pylori is crucial for the treatment of important diseases such as gastric cancer. Therefore, it seems that identifying the failure causes of treating this bacterium can be helpful in controlling the infections. Besides, further studies on new therapeutic strategies may help eradicate H. pylori in the future.

The Degree of Helicobacter pylori Infection Affects the State of Macrophage Polarization through Crosstalk between ROS and HIF-1α

Methods

The expression of CD86, CD206, and HIF-1α in the gastric mucosa was evaluated through immunohistochemistry. RAW 264.7 cells were cocultured with H. pylori at various multiplicities of infection (MOIs), and iNOS, CD86, Arg-1, CD206, and HIF-1α expression was detected by Western blot, PCR, and ELISA analyses. ROS expression was detected with the fluorescent probe DCFH-DA. Macrophages were also treated with the ROS inhibitor NAC or HIF-1α inhibitor YC-1.

Results

Immunohistochemical staining revealed that the macrophage polarization state was associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori affected macrophage polarization, and H. pylori enhanced the expression of ROS and HIF-1α in macrophages. A low MOI of H. pylori promoted both the M1 and M2 phenotypes, while a high MOI suppressed the M2 phenotype. Furthermore, ROS inhibition attenuated HIF-1α expression and switched macrophage polarization from M1 to M2. However, HIF-1α inhibition suppressed ROS expression and inhibited both the M1 phenotype and the M2 phenotype. Inhibition of ROS or HIF-1α also suppressed the activation of the Akt/mTOR pathway, which was implicated in H. pylori-induced macrophage polarization.

Conclusions

Macrophage polarization is associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori influences the macrophage polarization state. Crosstalk between ROS and HIF-1α regulates H. pylori-induced macrophage polarization via the Akt/mTOR pathway.

Helicobacter pylori infection impairs chaperone-assisted maturation of Na-K-ATPase in gastric epithelium

Helicobacter pylori infection always induces gastritis, which may progress to ulcer disease or cancer. The mechanisms underlying mucosal injury by the bacteria are incompletely understood. Here, we identify a novel pathway for H. pylori-induced gastric injury, the impairment of maturation of the essential transport enzyme and cell adhesion molecule, Na-K-ATPase. Na-K-ATPase comprises α- and β-subunits that assemble in the endoplasmic reticulum (ER) before trafficking to the plasma membrane. Attachment of H. pylori to gastric epithelial cells increased Na-K-ATPase ubiquitylation, decreased its surface and total levels, and impaired ion balance. H. pylori did not alter degradation of plasmalemma-resident Na-K-ATPase subunits or their mRNA levels. Infection decreased association of α- and β-subunits with ER chaperone BiP and impaired assembly of α/β-heterodimers, as was revealed by quantitative mass spectrometry and immunoblotting of immunoprecipitated complexes. The total level of BiP was not altered, and the decrease in interaction with BiP was not observed for other BiP client proteins. The H. pylori-induced decrease in Na-K-ATPase was prevented by BiP overexpression, stopping protein synthesis, or inhibiting proteasomal, but not lysosomal, protein degradation. The results indicate that H. pylori impairs chaperone-assisted maturation of newly made Na-K-ATPase subunits in the ER independently of a generalized ER stress and induces their ubiquitylation and proteasomal degradation. The decrease in Na-K-ATPase levels is also seen in vivo in the stomachs of gerbils and chronically infected children. Further understanding of H. pylori-induced Na-K-ATPase degradation will provide insights for protection against advanced disease.NEW & NOTEWORTHY This work provides evidence that Helicobacter pylori decreases levels of Na-K-ATPase, a vital transport enzyme, in gastric epithelia, both in acutely infected cultured cells and in chronically infected patients and animals. The bacteria interfere with BiP-assisted folding of newly-made Na-K-ATPase subunits in the endoplasmic reticulum, accelerating their ubiquitylation and proteasomal degradation and decreasing efficiency of the assembly of native enzyme. Decreased Na-K-ATPase expression contributes to H. pylori-induced gastric injury.

A positive Helicobacter pylori test is associated with low spondylarthritis incidence in a Danish historical cohort study

Ankylosing spondylitis (AS) and undifferentiated spondylarthritis (uSpA) are related inflammatory diseases affecting the spine and joints with infections among possible etiological factors. Helicobacter pylori (H. pylori) may affect the development of inflammatory diseases. Thus, we hypothesized that H. pylori infection affects AS and uSpA development. This cohort study was performed in Denmark with 56,000 patients from primary health care centers who were enrolled when a UBT was performed. They were followed for a median time of 8 years. From nationwide administrative registries, we extracted personal, diagnostic, and treatment information. Prevalence at time of UBT was studied on enrollment using logistic regression and incidence in the follow-up time of 8 years after UBT was studied using Cox regression, comparing H. pylori positive and H. pylori negative patients and adjusting for confounding variables. The prevalence of AS at the time of the UBT was higher among H. pylori positive individuals (OR = 2.00, CI 1.17-3.41), but likely to be linked to confounding as trends disappeared when stratifying for country of birth. The incidence of AS after UBT was lower for individuals who were previously H. pylori positive (OR = 0.23, CI 0.06-0.93). A similar phenomenon was observed for uSpA. As a novel finding, after UBT, the previously H. pylori infected individuals had lower risk of developing AS and uSpA compared to non-infected. This finding may be caused by etiological effects of previous H. pylori infection or unknown confounders. This suggests that H. pylori may somehow be positively involved in the pathogenesis of AS and uSpA.

The relationship between gastric microbiota and gastric disease

Traditionally, the stomach was believed to be a sterile organ unsuitable for microbiota growth. However, the discovery of H. pylori subverted this conception. With the development of molecular techniques, an abundance of microbiota of great diversity was found in the stomach. In addition, various lines of evidence suggest that the gastric microbiota plays a critical role in the development and progression of the gastric disease.The gastrointestinal microbiome plays an important role in various physiologic and pathologic processes.

Adapted first-line treatment of Helicobacter pylori infection in Algerian children

BACKGROUND

Helicobacter pylori (H. pylori) infection is acquired in early life and continues to have a high prevalence, especially in developing countries. Growing antibiotic-resistant strains necessitate adapted treatments. This study aimed to compare the efficacy, side effects, and influence of resistance of H. pylori strains between two different treatments.

METHODS

This prospective, randomized blind study enrolled 112 symptomatic children infected with H. pylori (66 girls, mean age 11.1 years). Treatments, allocated randomly irrespective of the susceptibility of the strains, were either the standard omeprazole-amoxicillin-clarithromycin combination for 7 days (OAC7; group A) or omeprazole-amoxicillin with a higher dose of metronidazole (40 instead of 20 mg/kg/d) for 10 days (OAM10; group B).

RESULTS

Before treatment, the resistance rates of H. pylori strains to metronidazole or clarithromycin were 37% and 13%, respectively, with 7% resistant to both antibiotics and neither to amoxicillin. Eradication rates obtained with OAM10 (80% by intention-to-treat [ITT] and 88% by per protocol [PP] analysis) were higher than with OAC7 (68% in ITT and 71% PP) and the differences (12% in ITT and 17% PP) were statistically significant (P=0.03). Successful treatments with OAM10 were obtained in metronidazole resistant strains and were more effective in children aged >10 years (P=0.02 by ITT and P=0.04 by PP). Only light or moderate side effects, mainly digestive, were observed.

CONCLUSION

Because of its therapeutic efficacy, good tolerance and lower cost the OAM10 can be considered as an appropriate first-line therapeutic scheme in Algeria.

Acid-regulated gene expression of Helicobacter pylori: Insight into acid protection and gastric colonization

BACKGROUND

The pathogen Helicobacter pylori encounters many stressors as it transits to and infects the gastric epithelium. Gastric acidity is the predominate stressor encountered by the bacterium during initial infection and establishment of persistent infection. H. pylori initiates a rapid response to acid to maintain intracellular pH and proton motive force appropriate for a neutralophile. However, acid sensing by H. pylori may also serve as a transcriptional trigger to increase the levels of other pathogenic factors needed to subvert host defenses such as acid acclimation, antioxidants, flagellar synthesis and assembly, and CagA secretion.

MATERIALS AND METHODS

Helicobacter pylori were acid challenged at pH 3.0, 4.5, 6.0 vs nonacidic pH for 4 hours in the presence of urea, followed by RNA-seq analysis and qPCR. Cytoplasmic pH was monitored under the same conditions.

RESULTS

About 250 genes were induced, and an equal number were repressed at acidic pHs. Genes encoding for antioxidant proteins, flagellar structural proteins, particularly class 2 genes, T4SS/Cag-PAI, F_o F₁ -ATPase, and proteins involved in acid acclimation were highly expressed at acidic pH. Cytoplasmic pH decreased from 7.8 at pH_out of 8.0 to 6.0 at pH_out of 3.0.

CONCLUSIONS

These results suggest that increasing extracellular or intracellular acidity or both are detected by the bacterium and serve as a signal to initiate increased production of protective and pathogenic factors needed to counter host defenses for persistent infection. These changes are dependent on degree of acidity and time of acid exposure, triggering a coordinated response to the environment required for colonization.

Non-invasive Diagnostic of Helicobacter pylori in Stools by Nested-qPCR

The aim of this study was to develop a non-invasive diagnostic test for the detection of Helicobacter pylori in stool samples from digestive symptomatic patients, using a new protocol of nested-qPCR. A total of 143 patients were invited to participate in the study. A gastric biopsy of each patient was collected for Rapid Urease Testing (RUT) and histology by Giemsa stain. A fecal sample for nested-qPCR analysis was also obtained. DNA was extracted from the fecal samples, and conventional PCR followed by qPCR of the ureC gene of H. pylori was carried out. We evaluated the presence of H. pylori, in 103 females and 40 males, mean (± SD) age of 56.5 ± 14.18. The sensitivity of RUT to detect the infection was 67.0% (95% C.I.: 57.2 - 75.8) and specificity was 92.3% (95% C.I.: 76.5 - 99.1). Histology by Giemsa stain, commonly used as a reference for H. pylori detection, showed a sensitivity of 98.6% (95% C.I.: 92.5 - 100.0) and a specificity of 89.7% (95% C.I.: 72.7 - 97.8). In contrast, detection of H. pylori infection in stools by nested-qPCR showed a sensitivity of 100% (95% C.I.: 94.9 - 100.0) and a specificity of 83.9% (95% C.I.: 66.3 - 94.6). Our test, based in nested-qPCR is a better diagnostic alternative than conventional RUT, and is similar to histology by Giemsa stain in the detection of H. pylori, by which the test could be used for non-invasive diagnosis in clinical practice.

Gut biofilm forming bacteria in inflammatory bowel disease

Inflammatory bowel disease (IBD) symbolizes a group of intestinal disorders in which prolonged inflammation occur in the digestive tract (esophagus, large intestine, small intestine mouth, stomach). Both genetic and environmental factors (infections, stress, diet) are involved in the development of IBD. As we know that bacteria are found in the intestinal mucosa of human and clinical observations revealed bacterial biofilms associated with patients of IBD. Various factors and microbes are found to play an essential role in biofilm formation and mucosal colonization during IBD. Biofilm formation in the digestive tract is dependent on an extracellular matrix synthesized by the bacteria and it has an adverse effect on the immune response of the host. There is no satisfactory and safe treatment option for IBD. Therefore, the current research aims to disrupt biofilm in IBD and concentrates predominantly on improving the drug. Here, we review the literature on bacterial biofilm and IBD to gather new knowledge on the current understanding of biofilm formation in IBD, host immune deregulation and dysbiosis in IBD, molecular mechanism, bacteria involved in biofilm formation, current and future regimen. It is urgently required to plan new ways to control and eradicate bacteria in biofilms that will open up novel diagnostic and therapeutic avenues for IBD. This article includes the mechanism of signaling molecules with respect to the biofilm-related genes as well as the diagnostic methods and new technologies involved in the treatment of IBD.

Helicobacter pylori infection is associated with reduced prevalence of colonic diverticular disease

BACKGROUND

Colonic diverticular disease is a common disorder with increasing incidence in Western societies. The intestinal microbiome may be among etiological factors. Helicobacter pylori may protect against some intestinal diseases, and incidence of H. pylori is decreasing in Western societies. Thus, we aimed to determine whether H. pylori is associated to decreased prevalence of registered colonic diverticular disease.

MATERIALS AND METHODS

In a historical cohort study, patients were enrolled from primary health care centers after urea breath test for H. pylori and then followed for a median of 6 years. The patient's diagnostic codes and country of birth were acquired from nationwide Danish administrative registries. We used logistic regression to compare prevalence and Cox regression to compare incidence of diverticular disease between H. pylori-positive and H. pylori-negative patients, adjusting for confounding variables.

RESULTS

Patients infected with H. pylori had lower prevalence of colonic diverticular disease (0.87% vs 1.14%, OR=0.62, 95% CI: 0.50-0.78). This phenomenon was observed whether we studied all registered diagnoses or only cases registered as primary diagnoses at discharge. After urea breath test, we observed no statistical difference in incidence rates of diverticular disease.

CONCLUSION

H. pylori is associated with reduced prevalence of colonic diverticular disease. The inverse association was absent after the urea breath test. Thus, we speculate that H. pylori may provide protection from colonic diverticular disease. Alternatively, H. pylori is a marker for other factors affecting disease development.

Are Synbiotics added to the Standard Therapy to eradicate Helicobacter pylori in Children Beneficial? A Randomized Controlled Study

Aim:

We aimed to evaluate the role of the addition of Bifidobacterium /actis-containing synbiotic to the triple therapy in the case of He/icobacter py/ori eradication, the dyspeptic symptoms, and reducing the side effects of antibiotics.

Materials and methods:

A total of 104 children aged between 5 and 17 years, who were histopathologically diagnosed with H. py/ori were enrolled in this study, of whom 100 were included in the analysis. Patients were randomly classified into two groups. In the first group, 50 patients were administered amoxicillin + clarithromycin + lansoprazole for 14 days and B. /actis-containing synbiotic. In the second group, 50 patients were treated with the standard triple therapy. All patients were given information after completion of therapy.

Results:

H. py/ori eradication was achieved in 88% in group I who received standard therapy with additional synbiotic and 72% in group II (p = 0.046). The number of patients in the second group who suffered from abdominal pain between the 3rd and 14th day of the treatment was higher (p < 0.05). The addition of probiotics to the triple therapy significantly reduced the frequency of diarrhea, but no significant difference was detected in the frequency of metallic taste (p = 0.04, p = 0.418 respectively).

Conclusion:

The addition of synbiotic to the triple therapy is effective for eradicating H. py/ori infection in children and is usually helpful to reduce or eliminate dyspeptic symptoms like abdominal pain, diarrhea, and vomiting. This study suggest that improved tolerance to the eradication treatment also reduces the treatment failure by adding probiotics and encourages the future study using probiotic supplementation in H. py/ori treatment.

How to cite this article: Şirvan BN, Usta MK, Kizilkan NU, Urganci N. Are Synbiotics added to the Standard Therapy to eradicate He/icobacter Py/ori in Children Beneficial? A Randomized Controlled Study. Euroasian J Hepato-Gastroenterol 2017;7(1):17-22.

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Background

Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients.

Methods

DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8.

Results

The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA.

Conclusions

Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.

Diagnosis of Helicobacter Pylori Infection is Associated with Lower Prevalence and Subsequent Incidence of Crohn's Disease

BACKGROUND AND AIMS

Helicobacter pylori infection may protect against some chronic inflammatory diseases. This study examined H. pylori infection and its association with the prevalence of the gastrointestinal diseases Crohn's disease [CD], ulcerative colitis [UC], and coeliac disease [CeD]. Incident cases in a follow-up period after H. pylori testing were recorded to investigate if protective effects of H. pylori persisted after probable eradication.

METHODS

This was a historical cohort study performed in the Central Denmark Region. Patients were enrolled consecutively from primary health care centres after a urea breath test [UBT] for H. pylori and were then followed for a median of 6 years. The patient's diseases, country of birth, and gender were acquired from nationwide administrative registries. We used logistic regression to compare the prevalences of CD, UC, and CeD and Cox regression to compare the incidences of CD, UC, and CeD between H. pylori-positive and H. pylori-negative patients, adjusting for confounding variables.

RESULTS

We found a lower prevalence of CD in H. pylori-positive than in H. pylori-negative patients (odds ratio = 0.36 [0.17-0.75]). There were fewer incident cases of CD in H. pylori-positive than H. pylori-negative patients in the follow-up period (hazard ratio = 0.59 [0.36-0.96]). Similar trends were found for CeD but not for UC.

CONCLUSIONS

H. pylori infection may be a protective factor against the development of CD. However, the incidence of CD is still reduced after UBT and probable H. pylori eradication; thus, H. pylori status may be a marker for other factors that protect against CD.

Mechanisms and therapeutic effectiveness of lactobacilli

The gut microbiome is not a silent ecosystem but exerts several physiological and immunological functions. For many decades, lactobacilli have been used as an effective therapy for treatment of several pathological conditions displaying an overall positive safety profile. This review summarises the mechanisms and clinical evidence supporting therapeutic efficacy of lactobacilli. We searched Pubmed/Medline using the keyword ‘Lactobacillus’. Selected papers from 1950 to 2015 were chosen on the basis of their content. Relevant clinical and experimental articles using lactobacilli as therapeutic agents have been included. Applications of lactobacilli include kidney support for renal insufficiency, pancreas health, management of metabolic imbalance, and cancer treatment and prevention. In vitro and in vivo investigations have shown that prolonged lactobacilli administration induces qualitative and quantitative modifications in the human gastrointestinal microbial ecosystem with encouraging perspectives in counteracting pathology-associated physiological and immunological changes. Few studies have highlighted the risk of translocation with subsequent sepsis and bacteraemia following probiotic administration but there is still a lack of investigations on the dose effect of these compounds. Great care is thus required in the choice of the proper Lactobacillus species, their genetic stability and the translocation risk, mainly related to inflammatory disease-induced gut mucosa enhanced permeability. Finally, we need to determine the adequate amount of bacteria to be delivered in order to achieve the best clinical efficacy decreasing the risk of side effects.

Challenges to the Treatment and New Perspectives for the Eradication of Helicobacter pylori

Helicobacter pylori (H. pylori) is one of the leading causes of gastric diseases such as chronic gastritis, peptic ulcer, and gastric adenocarcinoma. The current treatment of H. pylori infection with antibiotics and proton pump inhibitors has several limitations, including poor adherence and intrinsic patient-related factors, drug resistance, and the absence of adequate treatments. This review summarizes the current therapeutic approaches to eradicating H. pylori, the difficulties associated with its treatment, and several new perspectives aimed at improving existing treatment strategies.

Role of Helicobacter pylori infection in autoimmune systemic rheumatic diseases

The relationship between infection and autoimmunity has been increasingly defined over the last 20 years. The systemic rheumatic diseases are characterized by dysregulation of the immune system resulting in a loss of tolerance to self-antigen. The exact etiology for the majority of these diseases is unknown; however, a complex combination of host and environmental factors are believed to play a pivotal role. Helicobacter pylori (H. pylori) is one of the most widely studied infectious agents proposed as agents triggering autoimmune response. The persistent presence of H. pylori in the gastric mucosa results in chronic immune system activation with ongoing cytokine signaling, infiltration of gastric mucosa by neutrophils, macrophages, lymphocytes, as well as production of antibodies and effector T-cells. Various mechanisms have been proposed in an attempt to explain the extra-intestinal manifestations of H. pylori infections. These include: molecular mimicry, endothelial cell damage, superantigens and microchimerism. I performed a systematic literature review using the keywords “rheumatoid arthritis”, “Sjögren’s syndrome”, “systemic sclerosis”, “systemic lupus erythematosus”, “Helicobacter pylori” and “pathogenesis”. A systematic literature search was carried out in MEDLINE; EMBASE; Cochrane Library and ACR/EULAR meeting abstracts. In systemic rheumatic diseases H. pylori infection prevalence alone should not be expected to provide sufficient evidence for or against a pathologic role in the disease. In this article I review studies examining the potential involvement of H. pylori infection in autoimmune systemic rheumatic diseases. Further studies of the immunological response to H. pylori and its role in the pathogenesis of systemic rheumatic diseases are warranted.

Reduced genome size of Helicobacter pylori originating from East Asia

Helicobacter pylori (H. pylori), a major pathogen colonizing the human stomach, shows great genetic variation. Comparative analysis of strains from different H. pylori populations revealed that the genome size of strains from East Asia decreased to 1.60 Mbp, which is significantly smaller than that from Europe or Africa. In parallel with the genome reduction, the number of protein coding genes was decreased, and the guanine-cytosine content was lowered to 38.9%. Elimination of non-essential genes by mutations is likely to be a major cause of the genome reduction. Bacteria with a small genome cost less energy. Thus, H. pylori strains from East Asia may have proliferation and growth advantages over those from Western countries. This could result in enhanced capacity of bacterial spreading. Therefore, the reduced genome size potentially contributes to the high prevalence of H. pylori in East Asia.

Meta-analysis of randomized controlled trials on the efficacy of probiotics in Helicobacter pylori eradication therapy in children

The efficacy of probiotics supplementation in children undergoing Helicobacter pylori (H. pylori) eradication therapy remains controversial. This study aimed to meta-analyze whether probiotics supplementation in triple therapy could improve H. pylori eradication rates and reduce therapy-related side effects in children. Electronic databases PubMed and Embase were searched to identify all randomized controlled trials in pediatric patients comparing probiotics supplementation with placebo or no extra intervention in H. pylori eradication therapy. Two authors independently extracted the data. Results were expressed as odds ratios (ORs) and accompanying 95 % confidence intervals (CIs). Stata version 12.0 was used to perform all statistical analyses. Seven studies consisting of 508 pediatric patients were included in our study. The pooled ORs (studies n = 7) of eradication rates by intention-to-treat and per-protocol analysis in the probiotics group versus the control group were 1.96 (95 % CI 1.28-3.02) and 2.25 (95 % CI 1.41-3.57), respectively. The pooled OR (studies n = 5) of incidence of total side effects was 0.32 (95 % CI 0.13-0.79), with significant heterogeneity observed (I (2) = 71.9 %).

CONCLUSION

Probiotics supplementation in triple therapy for H. pylori infection may have beneficial effects on eradication and therapy-related side effects, particularly diarrhea, in children.

Detection of Helicobacter pylori in Oral Lesions

Background and aims. Helicobacter pylori is a microaerophilic gram-negative spiral organism. It is recognized as the etiologic factor for peptic ulcers, gastric adenocarcinoma and gastric lymphoma. Recently, it has been isolated from dental plaque and the dorsum of the tongue. This study was designed to assess the association between H. pylori and oral lesions such as ulcerative/inflammatory lesions, squamous cell carcinoma (SCC) and primary lymphoma.

Materials and methods. A total of 228 biopsies diagnosed as oral ulcerative/inflammatory lesions, oral squamous cell carcinoma (OSCC) and oral primary lymphoma were selected from the archives of the Pathology Department. Thirty-two samples that were diagnosed as being without any pathological changes were selected as the control group. All the paraffin blocks were cut for hematoxylin and eosin staining to confirm the diagnoses and then the samples were prepared for immunohistochemistry staining. Data were collected and analyzed.

Results. Chi-squared test showed significant differences between the frequency of H. pylori positivity in normal tissue and the lesions were examined (P=0.000). In addition, there was a statistically significant difference between the lesions examined (P=0.042). Chi-squared test showed significant differences between H. pylori positivity and different tissue types except inside the muscle layer as follows: in epithelium and in lamina propria (P=0.000), inside the blood vessels (P=0.003), inside the salivary gland duct (P=0.036), and muscle layer (P=0.122).

Conclusion. There might be a relation between the presence of H. pylori and oral lesions. Therefore, early detection and eradication of H. pylori in high-risk patients are suggested.

Helicobacter pylori impedes acid-induced tightening of gastric epithelial junctions

Gastric infection by Helicobacter pylori is the most common cause of ulcer disease and gastric cancer. The mechanism of progression from gastritis and inflammation to ulcers and cancer in a fraction of those infected is not definitively known. Significant acidity is unique to the gastric environment and is required for ulcer development. The interplay between gastric acidity and H. pylori pathogenesis is important in progression to advanced disease. The aim of this study was to characterize the impact of acid on gastric epithelial integrity and cytokine release and how H. pylori infection alters these responses. Human gastric epithelial (HGE-20) cells were grown on porous inserts, and survival, barrier function, and cytokine release were studied at various apical pH levels in the presence and absence of H. pylori. With apical acidity, gastric epithelial cells demonstrate increased barrier function, as evidenced by increased transepithelial electrical resistance (TEER) and decreased paracellular permeability. This effect is reduced in the presence of wild-type, but not urease knockout, H. pylori. The epithelial inflammatory response is also modulated by acidity and H. pylori infection. Without H. pylori, epithelial IL-8 release decreases in acid, while IL-6 release increases. In the presence of H. pylori, acidic pH diminishes the magnitude of the previously reported increase in IL-8 and IL-6 release. H. pylori interferes with the gastric epithelial response to acid, contributing to altered barrier function and inflammatory response. H. pylori diminishes acid-induced tightening of cell junctions in a urease-dependent manner, suggesting that local pH elevation promotes barrier compromise and progression to mucosal damage.

Comparison of the diagnostic accuracy of five different stool antigen tests for the diagnosis of Helicobacter pylori infection

BACKGROUND

Several noninvasive diagnostic tests based on the detection of Helicobacter pylori stool antigen (HpSA) have been developed. The aim of the study was to compare the diagnostic accuracy of 5 HpSA tests-2 monoclonal enzyme immunoassay tests (EIAs: the Premier Platinum HpSA Plus test and Helicobacter pylori Antigen (Hp Ag) test) and 3 rapid immunochromatographic assay (ICA) tests (the ImmunoCard STAT! HpSA test, one step HpSA test, and H. pylori fecal antigen test)--for diagnosing H. pylori infection in adult patients with dyspeptic symptoms before eradication therapy.

MATERIALS AND METHODS

A total of 198 patients with dyspeptic symptoms were included in the study. A gastric biopsy was collected for histopathology and rapid urease testing. Stool specimens for HpSA testing were also collected. Patients were considered H. pylori positive if two invasive tests (histological and rapid urease tests) were positive.

RESULTS

The sensitivity and specificity were 92.2% and 94.4%, respectively, for the Premier Platinum HpSA Plus test; 48.9% and 88.9%, respectively, for the HP Ag test; 86.7% and 88.9, respectively, for the One Step HpSA test; 68.9% and 92.6%, respectively, for the ImmunoCard STAT! HpSA test; and 78.9% and 87%, respectively, for the H. Pylori fecal antigen test.

CONCLUSIONS

The Premier Platinum HpSA Plus EIA test was determined to be the most accurate stool test for diagnosing H. pylori infections in adult dyspeptic patients. The currently available ICA-based tests are fast and easy to use but provide less reliable results.

Motor fluctuations and Helicobacter pylori in Parkinson's disease

The presence of Helicobacter pylori (HP) in the gastrointestinal tract may limit the absorption of levodopa. The objectives of this study were to investigate whether HP infection may affect the clinical response to levodopa as well as levodopa dose requirement in patients with Parkinson's disease (PD) as well as to investigate whether HP infection may affect plasma levels of vitamin B12, folic acid, and homocysteine. Seventy-five patients with PD diagnosed at least 4 years ago were included. Symptom fluctuations were assessed by UPDRS-IV and the WOQ9 wearing-off-scale. Plasma levels of vitamin B12, folic acid, and homocysteine were analyzed. Screening for HP was performed with a 13C-labeled urea breath test (Diabact UBT). A propensity-matched analysis was made where each patient in the HP-infected group was matched with one patient in the non-infected group with respect to age and gender. Of the 75 included patients, 20 were HP infected (27 %). Median Hoehn & Yahr scores were 3 in both HP infected patients and the matched group (n = 20). HP-infected patients had decreased "complications of therapy" with average total UPDRS-IV score of 4.8 ± 3.0 vs. 7.7 ± 3.8 (p < 0.05), despite no significant difference in levodopa equivalent dose. Wearing-off and sleep disturbance were significantly less common in the HP group (p < 0.05). There were no differences regarding vitamin B12, folic acid, or homocysteine values. HP infection in patients with PD may result in a decreased occurrence of symptom fluctuations according to this small study. This finding may be due to altered absorption of levodopa in the gastrointestinal tract in patients with HP infection, but further studies are required.

Microbial biofilms and gastrointestinal diseases

The majority of bacteria live not planktonically, but as residents of sessile biofilm communities. Such populations have been defined as 'matrix-enclosed microbial accretions, which adhere to both biological and nonbiological surfaces'. Bacterial formation of biofilm is implicated in many chronic disease states. Growth in this mode promotes survival by increasing community recalcitrance to clearance by host immune effectors and therapeutic antimicrobials. The human gastrointestinal (GI) tract encompasses a plethora of nutritional and physicochemical environments, many of which are ideal for biofilm formation and survival. However, little is known of the nature, function, and clinical relevance of these communities. This review summarizes current knowledge of the composition and association with health and disease of biofilm communities in the GI tract.

Relatedness of Helicobacter pylori populations to gastric carcinogenesis

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that infects half of the human population. The infection is associated with chronic inflammation of the gastric mucosa and peptic ulcers. It is also a major risk factor for gastric cancer. Phylogenetic analysis of global strains reveals there are seven populations of H. pylori, including hpAfrica1, hpAfrica2, hpEastAsia, hpEurope, hpNEAfrica, hpAsia2 and hpSahul. These populations are consistent with their geographical origins, and possibly result from geographical separation of the bacterium leading to reduced bacterial recombination in some populations. For each population, H. pylori has evolved to possess genomic contents distinguishable from others. The hpEurope population is distinct in that it has the largest genome of 1.65 mbp on average, and the highest number of coding sequences. This confers its competitive advantage over other populations but at the cost of a lower infection rate. The large genomic size could be a cause of the frequent occurrence of the deletion of the cag pathogenicity island in H. pylori strains from hpEurope. The incidence of gastric cancer varies among different geographical regions. This can be attributed in part to different rates of infection of H. pylori. Recent studies found that different populations of H. pylori vary in their carcinogenic potential and contribute to the variation in incidence of gastric cancer among geographical regions. This could be related to the ancestral origin of H. pylori. Further studies are indicated to investigate the bacterial factors contributing to differential virulence and their influence on the clinical features in infected individuals.

Helicobacter pylori infection increases the risk of colorectal adenomas: cross-sectional study and meta-analysis

BACKGROUND

The studies concerning the association between Helicobacter pylori status and colorectal adenoma, premalignant lesions of colorectal cancers, are not consistent.

METHODS

This cross-sectional study investigated the association of colorectal adenoma with H. pylori infection in a consecutive series of 2,195 asymptomatic average-risk subjects who underwent screening colonoscopy and H. pylori testing. Multivariate analyses were adjusted for potential relevant confounders, including age, sex, smoking, alcohol consumption, family history of colorectal cancer, and regular use of aspirin. Furthermore, we performed a systematic literature review and meta-analysis of available studies, including the current study, to clarify whether H. pylori infection is associated with an increased risk of colorectal adenoma.

RESULTS

Among 2,195 eligible subjects, 1,253 subjects were H. pylori seropositive and 942 subjects were seronegative. In the H. pylori (+) group, the prevalence of colorectal adenoma and advanced adenoma was significantly higher than in the H. pylori (-) group (25.3 vs. 20.1 %, p = 0.004 and 6.1 vs. 2.9 %, p < 0.001, respectively). In our multivariate analysis, H. pylori seropositivity was an independent risk factor for overall colorectal adenoma (OR = 1.36, 95 % CI = 1.10-1.68) and advanced adenoma (OR = 2.21, 95 % CI = 1.41-3.48). The positive association was confined in cases with any proximal adenoma. In the meta-analysis, which included ten studies and 15,863 patients, the pooled OR for colorectal adenoma related to H. pylori infection was 1.58 (95 % CI = 1.32-1.88).

CONCLUSION

Our results from this cross-sectional study and current studies included in our meta-analysis indicated that H. pylori infection was associated with a modest increase in the risk for colorectal adenoma.

A role for altered phagosome maturation in the long-term persistence of Helicobacter pylori infection

The vigorous host immune response that is mounted against Helicobacter pylori is unable to eliminate this pathogenic bacterium from its niche in the human gastric mucosa. This results in chronic inflammation, which can develop into gastric or duodenal ulcers in 10% of infected individuals and gastric cancer in 1% of infections. The determinants for these more severe pathologies include host (e.g., high IL-1β expression polymorphisms), bacterial [e.g., cytotoxicity-associated gene (cag) pathogenicity island], and environmental (e.g., dietary nitrites) factors. However, it is the failure of host immune effector cells to eliminate H. pylori that underlies its persistence and the subsequent H. pylori-associated disease. Here we discuss the mechanisms used by H. pylori to survive the host immune response and, in particular, the role played by altered phagosome maturation.

First degree relatives and familial aggregation of gastric cancer: who to choose for control in case-control studies?

Gastric carcinogenesis is a multifactorial process involving host gene and environmental interactions. Diverse case-control studies using different types of controls addressed the familial aggregation role for gastric cancer development. Our aim is to discuss the advantages and expected bias according to the different type of eligible controls. A PubMed search of papers on a query on first degree relatives of gastric cancer patients was conducted. The retrieved studies were evaluated regarding quality based on STROBE checklist. Data concerning risk of premalignant lesions and Helicobacter pylori infection was retrieved as the type of controls used on each study. Nine case-control studies were selected. A variety of controls were used ranging from general population to dyspeptic patients and spouses of the cases. We have observed that, independently of the type of control, the risk for the prevalence of premalignant lesions and H. pylori infection was higher for the cases. However, all of the evaluated case-control studies were average quality studies (mean 28 out of 45), with a small number of cases and controls (range from 39 to 300). Furthermore, concerning gene-environment interaction, each of the discussed type of control (general population, dyspeptic, spouse and neighbor) has potential advantages and disadvantages. The current data suggests that selection of any type of the aforementioned controls is feasible and seems to be mainly related to the feasibility of recruitment more than the genetic or environmental backgrounds. General population and dyspeptic patients would be equally appropriate for studies on familial aggregation of gastric cancer. Nevertheless, high-quality cohort studies are needed to validate this assumption.

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

OBJECTIVE

The effect of Helicobacter pylori on Barrett's esophagus is poorly understood. We conducted a meta-analysis to summarize the existing literature examining the effect that H. pylori has on Barrett's esophagus.

DESIGN

 We performed a comprehensive search to identify studies pertaining to the association between H. pylori and Barrett's esophagus. We conducted meta-regression analyses to identify sources of variation in the effect of H. pylori on Barrett's esophagus.

RESULTS

 Our analysis included a total of 49 studies that examined the effect of H. pylori on Barrett's esophagus and seven studies that examined the effect of cag A positivity on Barrett's esophagus. Overall, H. pylori, and even more so cag A, tended to be protective for Barrett's esophagus in most studies; however, there was obvious heterogeneity across studies. The effect of H. pylori on Barrett's esophagus varied by geographic location and in the presence of selection and information biases. Only four studies were found without obvious selection and information bias, and these showed a protective effect of H. pylori on Barrett's esophagus (Relative risk = 0.46 [95% CI: 0.35, 0.60]).

CONCLUSIONS

 Estimates for the effect of H. pylori on Barrett's esophagus were heterogeneous across studies. We identified selection and information bias as potential sources of this heterogeneity. Few studies without obvious selection and information bias have been conducted to examine the effect of H. pylori on Barrett's esophagus, but in these, H. pylori infection is associated with a reduced risk of Barrett's esophagus.

Antagonistic activities of lactobacilli against Helicobacter pylori growth and infection in human gastric epithelial cells

Lactobacilli have positive effects on bowel microflora and health in humans and animals. In this study, the antagonistic activities of Lactobacillus gasseri Chen, and L. plantarum 18 were assessed by agar plate diffusion assay and tests that determined the growth and urease activity of Helicobacter pylori cocultured with lactobacilli and the adherence of H. pylori to human gastric epithelial cells in the presence of lactobacilli. The results showed that the 2 Lactobacillus strains had significant anti-H.pylori activity, and this activity may be contributed by the cell-free supernatants (CFS) of lactobacilli and live Lactobacillus strains in vitro. The antagonistic activity of the CFS against H. pylori depended on the pH and the presence of metabolites, such as organic acids and proteases. Our results also indicated that 2 Lactobacillus strains could inhibit H. pylori adherence human gastric epithelial cells.

PRACTICAL APPLICATION

Helicobacter pylori causes chronic gastritis, peptic ulcer disease, and gastric cancer, and it infects about 50% of the world's population. Lactobacilli have been reported to have an inhibitory effect on H. pylori and can be used as probiotic to manufacture dairy products preventing H. pylori infection.

Influence of sociodemographic factors on Helicobacter pylori prevalence variability among schoolchildren in Leipzig, Germany. A long-term follow-up study

BACKGROUND

Until the beginning of this decade the assumption was that the Helicobacter pylori prevalence increases with the age of the population under consideration. More and more epidemiological studies have been suggestive of constancy in Helicobacter pylori prevalence, but to date there has been no long-term follow-up study in a large group of children confirming this hypothesis.

METHODS

Following up our study of H. pylori among school starters and 2nd graders in 1998 and 2000, we conducted a third phase of this study in 2006 using the [13C]-Urea Breath Test and a detailed parent-completed epidemiological questionnaire to evaluate the development of prevalence among the overall population of 8th graders in the city of Leipzig (n = 1,905), and especially of the subgroup of participants who took part in all three study phases (n = 751).

RESULTS

The overall H. pylori prevalence was 6.5% and had not significantly changed since 1998 and 2000 (6.1%, 5.7% respectively). However, we noticed a significant lower prevalence in the subgroup that participated in all study phases (2.7%). Moreover, we observed a dependence of prevalence on distribution of sociodemographic risk factors such as foreign nationality of at least one parent, birth outside of Germany, low parental education and unemployment, and > or = 2 older siblings.

CONCLUSION

The variability in prevalence is most likely a result of unequal sociodemographic family backgrounds.

Helicobacter pylori Infection, Intestinal Metaplasia, and Gastric Cancer Risk in Eastern Siberia

BACKGROUND

The incidence of gastric cancer (GC) is extremely high in Russia and eastern Siberia, where information on the epidemiology of Helicobacter pylori infection is fragmentary.

AIMS

To assess the prevalence of both H. pylori infection (including CagA status) and intestinal metaplasia (IM) in Russian and eastern Siberian populations carrying a different risk of GC.

MATERIALS AND METHODS

 A sample of 2129 consecutive patients was considered, including 689 Europoids and 1440 Mongoloids (493 Evenks, 533 Khakass people, and 414 Tuvans), who all underwent serum sampling and upper gastrointestinal endoscopy. H. pylori status was established (ELISA, urease test, and histology), and IgG anti-CagA antibodies were assessed (ELISA) in H. pylori-positive cases. At least 3 biopsy samples per patient were considered, and IM was scored as present versus absent. The prevalence of H. pylori, CagA+ve status, and IM was compared with the incidence of GC according to the regional cancer registries.

RESULTS

The prevalence of H. pylori was similar for the Europoids and Mongoloids (93.6 vs 94.3%). The prevalence of CagA+ve infection was as follows: Europoids 61.2%, Evenks 36.4%, Khakass 44.0%, Tuvans 60.0% (p(1vs2) < .001; p(1vs3) < .001; p(2vs4) < .001; p(3vs4) < .001). The prevalence of IM was as follows: Europoids 10.7%, Evenks 5.1%, Khakass 9.8%, and Tuvans 23.4% (p(1vs2) = .001; p(1vs4) < .001; p(2vs4) < .001; p(3vs4) < .001). The incidence of GC (per 100,000 population/year) was as follows: Europoids 33.2; Evenks 18.2; Khakass 20.2; Tuvans 50.7 (p(1vs2) = 0.04; p(1vs3) = .05; p(2vs4) < .001; p(3vs4) < .001).

CONCLUSION

 H. pylori infection is consistently high in Russian and eastern Siberian populations; ethnicities with similar prevalence of CagA+ve status had different prevalence of IM and incidence of GC. As expected, IM prevalence correlated with the incidence of GC. Host-related and/or environmental factors may explain discrepancies between H. pylori status, the prevalence of IM, and the incidence of GC.

Helicobacter pylori infection and systemic sclerosis-is there a link?

Over the last 20 years, increasing evidence has accumulated to implicate infectious agents in the etiology of systemic sclerosis (SSc) and Raynaud's phenomenon. Infection rates in patients with SSc compared with those in control populations do not provide clear support for any specific pathogen. However, increased antibody titers, a preponderance of specific strains in patients with SSc, and evidence of molecular mimicry inducing autoimmune responses suggest mechanisms by which infectious agents may contribute to the development and progression of SSc. Helicobacter pylori (H. pylori) has been associated with diseases such as autoimmune gastritis, Sjögren's syndrome, atherosclerosis, immune thrombocytopenia purpura, inflammatory bowel diseases and autoimmune pancreatitis, in each of which it seems to play a pathogenetic, but it has also been suggested that it may help to protect against the development of autoimmune gastritis, multiple sclerosis, systemic lupus erythemathosus and inflammatory bowel diseases. A systematic literature search was carried out in MEDLINE, EMBASE, Cochrane Library and ACR/EULAR meeting abstracts. We hypotheses that H. pylori infection might play a critical role in the pathogenesis of SSc. Here we review studies examining the potential involvement of H. pylori infection in SSc.

Ocular adnexal lymphoma and Helicobacter pylori gastric infection

There is a causal association between Helicobacter pylori (Hp) gastric infection and the development of gastric MALT lymphoma. In contrast, the link between Hp gastric infection and the development of extragastric lymphoma has not been thoroughly investigated. We, therefore, studied the prevalence of gastric Hp infection at initial diagnosis of ophthalmologic and nonophthalmologic extragastric lymphoma patients. Three cohorts of patients were studied: a first one of 83 patients with OAL, a second one of 101 patients with extraophthalmologic extragastric lymphoma, and a third one of 156 control individuals (control) without malignant lymphoma. Gastric Hp infection was investigated by histopathological analysis and Hp-specific PCR assay on gastric biopsy tissue samples. We found gastric Hp infection in 37 OAL patients (45%), in 25 extraophthalmologic extragastric lymphoma cases (25%), and in 18 controls individuals (12%) (P < 0.0001 OAL/C and P < 0.01 OAL/extra-OAL cases). Gastritis was found in 51% and 9% of Hp-positive and Hp-negative lymphoma patients, respectively (P < 10(-4)). Gastric Hp infection only correlated with MALT/LPL lymphoma (P = 0.03). There is a significant association between gastric Hp infection and MALT/LPL OAL. This suggests a novel mechanism of indirect infection-associated lymphomagenesis whereby chronic local antigen stimulation would lead to the emergence of ectopic B-cell lymphoma.

Two stomach-originated lactobacillus strains improve Helicobacter pylori infected murine gastritis

AIM: To investigate the potential anti-Helicobacter pylori (H. pylori) and anti-inflammation in vivo effects of two lactobacillus strains from human stomach.

METHODS: Forty H. pylori infected Balb/c mice were randomly divided into 4 groups: proton pump inhibitor and antibiotics triple treated group, Lactobacillus fermenti (L. fermenti) treated group, Lactobacillus acidophilus treated group and normal saline control group. Ten uninfected mice were also included as blank control group. The infection of H. pylori was detected by rapid urease tests, Giemsa staining and bacterial culture. The colonization of H. pylori was assessed in bacterial density score and gastric inflammation was assessed in histological score. The colonization of L. fermenti was performed by fluorescent probe.

RESULTS: Histopathologic evaluation showed significant release of mucosal inflammation in gastric antrum and gastric body in lactobacillus treated groups and triple treated group. H. pylori eradication rate in both lactobacillus treated groups and triple treated group were higher than normal saline control group. Lactobacillus treated groups and triple treated group showed significant decrease of H. pylori bacterial density.

CONCLUSION: Both lactobacillus strains have a significant anti-H. pylori activity; L. fermenti displays more efficient antagonistic activity in vivo against H. pylori infection.

Transmission pathway of Helicobacter pylori: does food play a role in rural and urban areas?

Helicobacter pylori is a Gram-negative microaerophilic bacterium that has colonized the human gastric mucosa. This infection is very common and affects more than half of the human population. The prevalence is however unbalanced between rural developing areas (more than 80%) and urban developed areas (less than 40%). H. pylori is responsible for several pathologies, such as gastritis, peptic ulcer and gastric cancer but its transmission pathway is still not clear. The risk factors for H. pylori infection include poor social and economic development; poor hygienic practices; absence of hygienic drinking water; and unsanitary prepared food. There is evidence supporting a gastro-oral, oral-oral and faecal-oral transmission, but no predominant mechanism of transmission has been yet identified. Transmission may occur in a vertical mode (e.g. from parents to child) or in a horizontal mode (across individuals or from environmental contamination). In either case, the involvement of water and food cannot be excluded as vehicles or sources of infection. Indirect evidence of presence of H. pylori in water and food, namely the detection of its DNA and survival studies after artificial contamination of food and water has been described. This paper reviews data both favourable and against the role of water and food in the transmission of H. pylori, exploring their role as a potential transmission vehicle for person-to-person and food-chain transmission. The likelihood of the transmission pathway in developing rural and developed urban areas appears to be different. In developed areas, person-to-person transmission within families appears to be dominant, while in the rural developing areas the transmission pathway appears to be more complex. In this later case, the transmission by contaminated food, water, or via intensive contact between infants and non-parental caretakers may have a greater influence than within-family transmission.

Comparative genomics of Helicobacter pylori

Genomic sequences have been determined for a number of strains of Helicobacter pylori (H pylori) and related bacteria. With the development of microarray analysis and the wide use of subtractive hybridization techniques, comparative studies have been carried out with respect to the interstrain differences between H pylori and inter-species differences in the genome of related bacteria. It was found that the core genome of H pylori constitutes 1111 genes that are determinants of the species properties. A great pool of auxillary genes are mainly from the categories of cag pathogenicity islands, outer membrane proteins, restriction-modification system and hypothetical proteins of unknown function. Persistence of H pylori in the human stomach leads to the diversification of the genome. Comparative genomics suggest that a host jump has occurs from humans to felines. Candidate genes specific for the development of the gastric diseases were identified. With the aid of proteomics, population genetics and other molecular methods, future comparative genomic studies would dramatically promote our understanding of the evolution, pathogenesis and microbiology of H pylori.

Helicobacter pylori em crianças e associação de cepas CagA na transmissão mãe-filho na Amazônia brasileira

Investigou-se a prevalência de infecção pela Helicobacter pylori em amostras de sangue de 100 crianças de 1 a 12 anos e de suas mães através dos métodos de hemaglutinação indireta e anti-CagA pelo ensaio ELISA. Destas 100 crianças, foram obtidas 79 amostras de fezes e realizada pesquisa de antígenos da bactéria nas fezes por ELISA de captura. Os antígenos foram detectados em 54,4% (43/79) das crianças, e os anticorpos no soro em 43% (34/79), métodos que apresentaram desempenhos semelhantes, com maiores discordâncias nas crianças de 1 a 4 anos. A soroprevalência nas crianças foi de 50% (50/100) e nas mães de 86% (86/100). Mães infectadas representaram fator de risco 19 vezes superior ao de mães soronegativas para determinar infecção em seus filhos (p < 0,05), sobretudo as mães com cepas CagA+ (p < 0,05). O contato direto pessoa-pessoa pode ser um modo de transmissão desta infecção.

Prevalence of Helicobacter pylori infection and identification of risk factors in rural and urban Beijing, China

BACKGROUND

The prevalence of Helicobacter pylori is higher in developing countries such as China. The aim of this study was to investigate the prevalence of H. pylori in one rural and one urban region of Beijing, China.

MATERIALS AND METHODS

Healthy individuals in rural Pinggu and urban Haidian voluntarily participated in this study. The diagnosis of H. pylori infection was reached using the (13)C-urea breath test. Associations between H. pylori and sex, age, living area (i.e. rural vs urban), education level, smoking, and alcohol consumption were evaluated.

RESULTS

Of the 1232 included subjects, 54.7% of tested individuals residing in Pinggu and 41.3% in Haidian were positive for H. pylori. In urban region, more individuals were negative for H. pylori (429 of 731), whereas in the rural region, more individuals were positive for H. pylori (p < .05). Univariate analysis identified geographic area and lower education and annual income as significant factors associated with H. pylori. Men in rural areas were more likely than women in rural areas to be infected, and both men and women in the rural area were more likely to be positive for H. pylori than men and women in the urban area (all p < .05).

CONCLUSIONS

H. pylori infection is common in both rural and urban regions of Beijing. Residing in a rural area, having a lower family income, and lower education level are significant risk factors associated with infection.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.