Recent developments in the epidemiology of Helicobacter pylori

How well is Helicobacter pylori treated in usual practice?

BACKGROUND

Helicobacter pylori is a WHO class I carcinogen also associated with nonmalignant gastrointestinal diseases. Effective treatment exists, and all persons infected with H pylori should receive treatment. However, data regarding the rates of treatment prescription in clinical practice are lacking.

OBJECTIVE

To determine the rates of H pylori treatment in usual practice.

METHODS

Patients with histological evidence of H pylori infection between January 1, 2007, and December 31, 2007, at Sunnybrook Health Sciences Centre (Toronto, Ontario) were identified. Charts were reviewed to determine the rates of H pylori treatment and confirmation of eradication, when indicated. Questionnaires were subsequently sent to endoscopists of patients identified as not having received treatment to determine the reasons for lack of treatment.

RESULTS

A total of 102 patients were H pylori positive and were appropriate candidates for treatment, of whom 58 (57%) were male and 78 (76%) were outpatients, with 92 (90%) receiving eradication therapy. When indicated, 15 of 22 (68%) patients received confirmation of eradication, 13 of 18 (72%) patients underwent repeat endoscopy and 86% received complete therapy. Outpatients were more likely to receive eradication therapy (OR 10.3 [95% CI 2.6 to 40.4]; P=0.001) and complete therapy (OR 13.2 [95% CI 3.8 to 45.7]; P=0.0001) compared with inpatients. Having a follow-up appointment resulted in higher treatment rates (OR 12.0 [95% CI 3.0 to 47.5]; P=0.001).

CONCLUSION

During the time period studied, adequate rates of H pylori treatment were achieved in outpatients and patients who had formal follow-up at Sunnybrook Health Sciences Centre. However, some aspects of care remain suboptimal including treatment of inpatients and care following treatment. Additional studies are required to identify strategies to improve the care of patients infected with H pylori.

Treatment for Eradication of Helicobacter pylori Infection among Chronic Hepatitis C Patients

BACKGROUND/AIMS

Helicobacter pylori infection causes gastritis, peptic ulcers and gastric malignancies, and its eradication has been advocated by many groups. We determined the H. pylori carrier status and eradication rates of patients with chronic hepatitis C virus (HCV) infection.

METHODS

In total, 76 chronically HCV-infected patients were enrolled for comparison with 228 HCV-noninfected, age- and sex-matched controls. H. pylori infection was confirmed by H. pylori antibody and urea breath testing.

RESULTS

The H. pylori infection rate was significantly higher for HCV-infected patients (67 of 76, 88.2%) than for HCV-noninfected controls (158 of 228, 69.3%). Endoscopic findings showed that the rates of gastric ulcers and gastritis were significantly higher for the 67 HCV-infected patients with H. pylori infection (34.3% and 77.6%) than for the 158 HCV-noninfected controls with H. pylori infection (15.2% and 57.6%). Treatment to eradicate H. pylori had a significantly higher success rate for HCV-infected patients (61 of 67, 91.0%) than for HCV-noninfected controls (115 of 158, 72.8%).

CONCLUSIONS

The markedly high H. pylori eradication rate observed in this study shows that eradication of H. pylori holds promise for the improvement of the long-term health condition of patients with chronic HCV infection.

A randomized trial of standard-dose versus half-dose rabeprazole, clarithromycin, and amoxicillin in the treatment of Helicobacter pylori infection

OBJECTIVES

To evaluate the efficacy and safety of a standard-dose versus half-dose 10-day triple regimen for the eradication of Helicobacter pylori infection.

METHODS

A total of 115 consecutive patients with documented infection were enrolled in this open-label trial. Group A (standard dose) received rabeprazole (20 mg), amoxicillin (1 g), and clarithromycin (500 mg), all twice daily for 10 days. Group B (half dose) received rabeprazole (10 mg), amoxicillin (500 mg), and clarithromycin (250 mg), all twice daily for 10 days. (14)C urea breath tests were performed a minimum of 4 weeks after treatment and a minimum of 2 weeks off any acid-suppressive therapy. Compliance and adverse effects were evaluated throughout the treatment period.

RESULTS

A total of 115 patients were enrolled (59 women and 56 men; mean age 47.1±14.0 years). Eradication occurred in 45 of 58 patients [77.6%; 95% confidence interval (CI): 66.9-88.3%] in the standard-dose group versus 44 of 57 in the half-dose group (77.2%; 95% CI: 66.3-88.1%) on an intent-to-treat (ITT) analysis (P=1.00). Per protocol eradication rates were 45 of 57 (78.9%; 95% CI: 68.4-85.9%) and 44 of 54 (81.5%; 95% CI: 71.1-91.8%), respectively (P=0.81). The number of patients reporting any adverse effect was significantly higher in the standard-dose group (64.9 vs. 40.4%; P=0.014). The cost of treatment was significantly less in patients receiving the half-dose regimen (ITT analysis; P<0.05). The number needed to harm to suffer one additional failure in the half-dose over the standard-dose arm was 250 (ITT analysis).

CONCLUSION

A half-dose 10-day regimen of rabeprazole, amoxicillin, and clarithromycin is equally effective but cheaper and better tolerated than its standard-dose regimen in the treatment of Helicobacter pylori. Eradication rates of both regimens are, however, suboptimal compared with accepted standards.

Helicobacter pylori and autoimmune diseases

Helicobacter pylori (H. pylori) is a widely prevalent microbe, with between 50 and 80% of the population infected worldwide. Clinically, infection with H. pylori is commonly associated with peptic ulcer disease, but many of those infected remain asymptomatic. H. pylori has evolved a number of means to affect the host immune response and has been implicated in many diseases mitigated by immune dysregulation, such as immune thrombocytopenic purpura (ITP), atrophic gastritis, and mucosa associated lymphoid tissue (MALT) lymphoma. Autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and Sjogren's syndrome, are the result of a dysregulated host immune system which targets otherwise healthy tissues. The exact etiology of autoimmune diseases is unclear, but it has long been suggested that exposure to certain environmental agents, such as viral and bacterial infection or chemical exposures, in genetically susceptible individuals may be the catalyst for the initiation of autoimmune processes. Because of its prevalence and ability to affect human immune function, many researchers have hypothesized that H. pylori might contribute to the development of autoimmune diseases. In this article, we review the available literature regarding the role of chronic H. pylori infection in various autoimmune disease states.

The occupational risk of Helicobacter pylori infection among gastroenterologists and their assistants

BACKGROUND

Helicobacter pylori is a widely spread bacterium that mainly inhabits the gastric mucosa and can lead to serious illnesses such as peptic ulcer disease, gastric carcinoma and gastric MALT lymphoma. The oral-oral route seems to be the main transmission route. The fact that endoscopes are contaminated after being used to perform a gastroscopy leads one to question whether gastroenterologists and endoscopy nurses and assistants run a higher risk of infection.

METHODS

A systematic search for literature was conducted in the MEDLINE and EMBASE databases and further publications were found in reference lists of relevant articles. Epidemiological studies on the occupational exposure of endoscopy personnel were collected and their quality was assessed. Pooled effect estimates were identified in a meta-analysis.

RESULTS

Of the 24 studies included in the analysis, 15 were considered to be methodologically good. Of these 15 studies, eight single studies showed a statistically significant increased risk of infection for gastroenterologists, and five for their assistants. Meta-analysis across all methodologically good studies found a statistically significant risk of 1.6 (95%CI 1.3-2.0) for doctors. The pooled effect estimates also indicated a statistically significant risk of Helicobacter pylori infection (RR 1.4; 95%CI 1.1-1.8) for assistants too.When studies are stratified by medical and non-medical control groups, statistically significant risks can only be recognised in the comparison with non-medical controls.

CONCLUSIONS

In summary, our results demonstrated an increased risk of Helicobacter pylori infection among gastroenterological personnel. However, the choice of control group is important for making a valid assessment of occupational exposure risks.

Molecular cross-talk between Helicobacter pylori and human gastric mucosa

Helicobacter pylori (H. pylori) has co-evolved with humans to be transmitted from person to person and to colonize the stomach persistently. A well-choreographed equilibrium between the bacterial effectors and host responses permits microbial persistence and health of the host, but confers a risk for serious diseases including gastric cancer. During its long coexistence with humans, H. pylori has developed complex strategies to limit the degree and extent of gastric mucosal damage and inflammation, as well as immune effector activity. The present editorial thus aims to introduce and comment on major advances in the rapidly developing area of H. pylori/human gastric mucosa interaction (and its pathological sequelae), which is the result of millennia of co-evolution of, and thus of reciprocal knowledge between, the pathogen and its human host.

Effect of eradication of Helicobacter pylori in children with chronic immune thrombocytopenia: a prospective, controlled, multicenter study

BACKGROUND

The eradication of Helicobacter pylori has been associated with remission of immune thrombocytopenia (ITP) in approximately half of eradicated patients. Data on children are limited to small case series.

PROCEDURE

Children from 16 centers in Italy, who were less than 18 years of age and diagnosed with chronic ITP (cITP), were screened for H. pylori infection. Positive patients underwent standard triple therapy with amoxicillin, clarithromycin, and omeprazole. The eradication response was defined as follows: complete response, platelet (PLT) count ≥ 150 × 10(9) /L; partial response, PLT count of at least 50 × 10(9) /L; no response, PLT count <50 × 10(9) /L.

RESULTS

Of 244 screened patients, 50 (20%) had H. pylori infection, 37 of which received eradication therapy and completed follow-up. Eradication was successful in 33/37 patients (89%). PLT recovery was demonstrated in 13/33 patients after eradication (39%), whereas spontaneous remission was observed in 17/166 (10%) H. pylori-negative patients (P < 0.005). Responders more often required second line eradication (9/13), whereas a second cycle was required in 3/20 non-responders (P < 0.005).

CONCLUSIONS

Among the large cohort of patients, those who underwent successful H. pylori eradication showed a significantly higher PLT response. Therefore, it may be appropriate to look for H. pylori and eventually eradicate it in children with cITP.

Helicobacter pylori and gastritis: Untangling a complex relationship 27 years on

Since its' introduction by Warren and Marshall 27 years ago, Helicobacter pylori (HP) has become the linchpin in our understanding of important gastric conditions including gastritis, intestinal metaplasia (IM), gastric/duodenal ulcers (GU/DU), Mucosal Associated Lymphoid Tumour (MALToma) and gastric cancer. Initially named Campylobacter pyloridis, it was re-named HP when biochemical and genetic characterization of the organism showed that it was not a member of the Campylobacter genus. The finding in 1983 was seminal. It is now recognized that HP is the most common chronic human bacterial infection and it is the most common cause of gastritis. It is strongly implicated in the development of peptic ulcer disease and gastric neoplasms. In the years since its' discovery, much headway has been made in the understanding of this ubiquitous organism that had remained elusive, with much work focused on eradication, in part driven by pharmaceutical research and development. Standard triple therapy emerged to eradicate HP. However, with the emergence of HP resistance, newer regimes have been put forth that include quadruple therapy, sequential therapy and a dizzying array of other combinations bent on eradicating HP. Much less is known about the natural history of HP, the different faces of HP internationally, HP eradication and its effect on gastritis, IM, GU/DU and gastric cancer. This review will address the changing face of HP in 2011.

Helicobacter pylori and gastric cancer: factors that modulate disease risk

Helicobacter pylori is a gastric pathogen that colonizes approximately 50% of the world's population. Infection with H. pylori causes chronic inflammation and significantly increases the risk of developing duodenal and gastric ulcer disease and gastric cancer. Infection with H. pylori is the strongest known risk factor for gastric cancer, which is the second leading cause of cancer-related deaths worldwide. Once H. pylori colonizes the gastric environment, it persists for the lifetime of the host, suggesting that the host immune response is ineffective in clearing this bacterium. In this review, we discuss the host immune response and examine other host factors that increase the pathogenic potential of this bacterium, including host polymorphisms, alterations to the apical-junctional complex, and the effects of environmental factors. In addition to host effects and responses, H. pylori strains are genetically diverse. We discuss the main virulence determinants in H. pylori strains and the correlation between these and the diverse clinical outcomes following H. pylori infection. Since H. pylori inhibits the gastric epithelium of half of the world, it is crucial that we continue to gain understanding of host and microbial factors that increase the risk of developing more severe clinical outcomes.

Helicobacter pylori CagA protein polymorphisms and their lack of association with pathogenesis

AIM

To investigate Helicobacter pylori (H. pylori) CagA diversity and to evaluate the association between protein polymorphisms and the occurrence of gastric pathologies.

METHODS

One hundred and twenty-two clinical isolates of H. pylori cultured from gastric biopsies obtained from Colombian patients with dyspepsia were included as study material. DNA extracted from isolates was used to determine cagA status, amplifying the C-terminal cagA gene region by polymerase chain reaction. One hundred and six strains with a single amplicon were sequenced and results were used to characterize the 3' variable region of the cagA gene. To establish the number and type of tyrosine phosphorylation motifs Glutamine acid-Proline-Isoleucine-Tyrosine-Alanine (EPIYA) bioinformatic analysis using Amino Acid Sequence Analyzer-Amino Acid Sequence Analyzer software was conducted. Analysis of the association between the number of EPIYA motifs and the gastric pathology was performed using chi(2) test and analysis of the presence of EPIYA-C motifs in relation to the pathology was made by logistic regression odds ratios. Comparisons among EPIYA types found and those reported in GenBank were performed using a proportion test in Statistix Analytical Software version 8.0.

RESULTS

After amplification of the 3' of the cagA gene, 106 from 122 isolates presented a single amplicon and 16 showed multiple amplicons. As expected, diversity in the size of the cagA unique fragments among isolates was observed. The 106 strains that presented a single amplicon after 3' cagA amplification came from patients with gastritis (19 patients), atrophic gastritis (21), intestinal metaplasia (26), duodenal ulcer (22) and gastric cancer. DNA sequence analysis showed that the differences in size of 3' cagA unique fragments was attributable to the number of EPIYA motifs: 1.9% had two EPIYA motifs, 62.3% had three, 33.0% had four and 2.8% had five motifs. The majority of tested clinical strains (62.3%) were found to harbor the ABC combination of EPIYA motifs and a significant statistical difference was observed between the frequencies of ABCC tyrosine phosphorylation motifs and Western strains sequences deposited in GenBank.

CONCLUSION

The present report describes a lack of association between H. pylori CagA-protein polymorphisms and pathogenesis. ABCC high frequency variations compared with Western-strains sequences deposited in GenBank require more investigation.

Trends in incidence of oesophageal and stomach cancer subtypes in Europe

OBJECTIVE

Time trend studies in the USA have shown that the incidences of adenocarcinomas of the oesophagus and gastric cardia have risen strongly since the 1970s, whereas the incidence of squamous cell carcinomas of the oesophagus has declined. Earlier, we found that the incidence of these adenocarcinomas also rose in some European countries until the early 1990s. The main goal of this study was to investigate more recent trends in the incidence of oesophageal and stomach cancer subtypes in the European countries.

METHODS

Eurocim cancer incidence data of 23 cancer registries from 13 European countries were used to investigate the incidence trends in oesophageal and stomach cancer subtypes during the 1983-1997 period. We calculated estimated annual percentage changes (EAPCs) in European age-standardized incidence rates and 95% confidence intervals.

RESULTS

The incidence of adenocarcinomas of the oesophagus and gastric cardia rose in most, but not all, registration areas (EAPCs were usually 1-7%), the strongest in the UK and Ireland. Oesophageal squamous cell carcinoma incidence rose mostly in Northern European and Slovakian men (EAPCs: 1-5%) and in women from all regions (EAPCs: 1-8%), but declined mostly in Southern and Western European men (EAPCs: -1 to -5%).

CONCLUSION

Our results are partly in line with earlier findings on adenocarcinomas of the oesophagus and gastric cardia. There was, however, substantial heterogeneity in trends of subtypes of these cancers within Europe. There may be different risk factors for these cancers, and the prevalence of these risk factors may differ among countries.

Neither genotype nor the gastric colonization site of Helicobacter pylori are predictive factors for the development of erosive esophagitis in patients with peptic ulcer disease, 1 year after eradication

CONTEXT

Whether Helicobacter pylori infection is a protective or predisposing factor for the development of gastroesophageal reflux disease remains controversial. The most virulent strains, such as those expressing the cytotoxin-associated gene A (CagA), and the site of gastric colonization have been correlated with the prevention or development of esophagitis.

AIM

To determine the incidence of erosive esophagitis following eradication of H. pylori in patients with peptic ulcer disease and to evaluate the association of erosive esophagitis with virulent strains of H. pylori and the site of gastric colonization.

METHODS

Triple therapy with lansoprazole, amoxicillin and clarithromycin was administered to 159 patients with peptic ulcer disease. Endoscopy, histopathology, urease and carbon-14 urea breath tests were performed prior to treatment, at 3 months and 1 year following treatment. Genotyping of H. pylori strains using polymerase chain reaction was performed separately on samples from the corpus and antrum.

RESULTS

One year after treatment, 148 successfully treated patients were reevaluated. Twenty-eight patients (19%) had erosive esophagitis, classified as Los Angeles grade A in 24 and B in 4. The samples taken from the corpus were CagA-positive in 18 patients (64%), while the samples taken from the antrum were CagA-positive in 21 patients (75%).

CONCLUSIONS

The incidence of erosive esophagitis in peptic ulcer patients who had their H. pylori eradicated was 19%. No correlation was found between the gastric site colonized by H. pylori or strains expressing CagA and the prevention or development of erosive esophagitis in patients with peptic ulcer disease, 1 year after infection eradication.

Molecular Genetics of Gastric Adenocarcinoma

Gastric carcinoma is the second leading cause of cancer deaths in the world. Its aetiology is closely linked to the bacterial pathogen Helicobacter pylori which is believed to induce a state of chronic inflammation that predisposes to a cascade of molecular and cellular alterations leading to carcinogenesis. Although the exact process of gastric carcinogenesis has yet to be elucidated fully, the interaction of the genetic factors with environmental factors is likely to be a significant consideration. Numerous genes and molecular pathways have been discovered to be associated with gastric adenocarcinoma and more importantly, it is now becoming possible to use some of these as means of prognostication and targeted therapy. This review will outline our current understanding of the aetiology and molecular genetics of gastric adenocarcinoma and its current clinical applications.

Clinicopathological features and prognostic factors of proximal gastric carcinoma in a population with high Helicobacter pylori prevalence: a single-center, large-volume study in Korea

BACKGROUND

The incidence of gastric cancers has fallen in recent decades. However, a substantial reduction in Helicobacter pylori prevalence and a substantial increase in the incidence of proximal gastric cancer (PGC) have been observed in the West and Japan, but not in other East Asian countries. The purpose of this large-volume study was to analyze prevalence, clinicopathological features, and prognosis of PGC compared with other types of gastric cancer in Korea, where there is high incidence of H. pylori infection.

METHODS

Between 2000 and 2005, a total of 3,193 patients were enrolled. We analyzed clinicopathological features and survival outcomes.

RESULTS

Chronological analysis showed increasing incidence of PGC over the study period. PGC patients were younger and had higher incidence of Bormann types III and IV than did distal gastric cancer (DGC) patients. Also, PGC was associated with a significantly higher proportion of poorly differentiated type, T3 and T4 stage, and positive lymph nodes compared with DGC. Peritoneal and other distant metastases were more common in PGC group than in DGC group. The 5-year survival rate was significantly lower in PGC than in DGC group, regardless of curative resection. Also, the N0 and N1 category significantly influenced the 5-year survival rate. Tumor-node-metastasis (TNM) stage, hepatic metastasis, and curative resection were significant prognostic factors in PGC patients.

CONCLUSIONS

PGC has increased in incidence with the respective decline in H. pylori prevalence in Korea. Survival was worse for patients with PGC than for those with DGC, regardless of curative respectability. PGC is often diagnosed at more advanced stage than other gastric cancers, and therefore early detection is critical for successful treatment.

Helicobacter pylori seroprevalence in symptomatic veterans: a study of 7310 patients over 11 years

BACKGROUND AND AIMS

The prevalence of Helicobacter pylori infection has been decreasing in the USA, but recent data are lacking. This study evaluates the seroprevalence for anti-H. pylori antibodies in symptomatic veterans tested over the past 11 years.

MATERIALS AND METHODS

The same serum anti-H. pylori IgG detection system has been used at a tertiary care Veterans Affairs hospital since late 1996. Results of all tests performed from 1997 to 2007 were analyzed.

RESULTS

Of 7310 unique patients tested, 3982 (54.5%) were positive. Seropositivity declined from 70.8% in 1997 to 48.6% in 2002, then reached a plateau around 50%. A strong birth cohort effect was present, from a seropositivity of 72.7% for the veterans born before 1920 to 22% for those born between after 1980.

CONCLUSIONS

Despite a constant birth cohort effect, H. pylori seropositivity among symptomatic veterans leveled down at approximately 50% after declining steadily from 1997 to 2002.

Helicobacter pylori infection in patients with chronic urticaria: correlation with pathologic findings in gastric biopsies

BACKGROUND

Chronic urticaria is a persistent urticaria lasting longer than 6 weeks, affecting 20% of the general population. Various infectious agents have been reported as causes of urticaria, including Helicobacter pylori, which is a common worldwide bacterial infection. Its role in inducing allergic conditions, such as chronic urticaria, has been suggested in some reports and ignored in others.

AIMS

To assess the prevalence of H. pylori infection in patients with chronic urticaria and to explore the possible etiopathogenetic link between them.

METHODS

Thirty-five patients suffering from chronic urticaria and 10 normal control individuals were subjected to upper endoscopic gastric biopsies to assess and semiquantify H. pylori infection and to address other pathologic abnormalities, using routine hematoxylin and eosin staining and Giemsa staining.

RESULTS

Forty percent of control subjects and 57% of patients were positive for H. pylori infection, but the difference did not reach statistically significant levels (P = 0.47). The severity of urticarial symptoms was greater in the H. pylori-positive than in the H. pylori-negative group (P = 0.019). Heavy bacterial colonization (P = 0.008) and intense gastric inflammation (P < 0.0001) were associated significantly with severe clinical manifestations. Eighty percent of the H. pylori-positive urticaria group experienced complete remission after receiving eradication therapy for H. pylori.

CONCLUSIONS

Helicobacter pylori may have a role in the exacerbation of urticarial symptoms, even though it is not involved directly in its etiology, and its eradication may lead to symptom improvement in a considerable number of infected urticaria patients. The severity of symptoms is dependent on the density of bacterial infection and the intensity of inflammatory infiltrate in the gastric biopsy.

Absence of platelet recovery following Helicobacter pylori eradication in childhood chronic idiopathic thrombocytopenic purpura: a multi-center randomized controlled trial

OBJECTIVE

To investigate the effect of Helicobacter pylori eradication on platelet recovery in childhood chronic idiopathic thrombocytopenic purpura (ITP).

PATIENTS AND METHODS

A multi-center randomized controlled trial was conducted. Patients aged 4-18 years, diagnosed with chronic ITP, defined by platelet count below 100 x 10(9)/L lasting more than 6 months without identified causes, were enrolled and underwent (13)C-urea breath test for diagnosis of H. pylori infection. Patients who received prednisolone more than 0.5 mg/kg per day or received other platelet-enhancing therapy were excluded. Patients with H. pylori infection were randomized into two groups: treatment and control groups. Treatment group received a standard protocol for H. pylori eradication and repeated (13)C-UBT at 4-6 weeks to confirm successful therapy while the control group received no specific treatment. Monthly platelet count was monitored for 6 months in both groups. Primary outcome was platelet recovery, defined by platelet count over 100 x 10(9)/L for at least 3 months.

RESULTS

Of the 55 ITP children, 16 (29.1%) had H. pylori infection. There were no differences in age, sex, duration of disease, platelet count, and the dose of prednisolone between the treatment group (n = 7) and control group (n = 9). One patient in control group was withdrawn due to massive gastrointestinal bleeding requiring a high dose prednisolone. At 6 months, platelet recovery was demonstrated in one patient in the treatment group as well as one in the control group.

CONCLUSION

No beneficial effect of H. pylori eradication on platelet recovery in childhood chronic ITP was identified.

Helicobacter pylori infection rate decreases in symptomatic children: a retrospective analysis of 13 years (1993-2005) from a gastroenterology clinic in West Virginia

BACKGROUND

The rate of Helicobacter pylori is decreasing in the developed countries, but few long-term studies are available from the United States. We retrospectively assessed the annual H. pylori infection rate in symptomatic children seen in our clinic over a 13-year study period.

STUDY

A retrospective analysis of all children who had histologic diagnosis of H. pylori infection between January 1993 and December 2005 in our pediatric gastroenterology clinic was performed. The annual infection rate and the overall infection rate were calculated.

RESULTS

A total of 1743 upper endoscopy reports were reviewed, of which 212 (12.1%) were diagnosed with H. pylori infection. A significant decrease in mean annual H. pylori infection rate was noted in the last 6 years of the study period (2000 to 2005), compared with the first 7 years (1993 to 1999) (18.2% vs. 7.3%, respectively; P=0.001).

CONCLUSIONS

The incidence of H. pylori infection in symptomatic children in our clinic is decreasing. A national multicenter study will be needed to assess whether this drop is a local phenomenon or a national trend.

Roles of gastric mucin-type O-glycans in the pathogenesis of Helicobacter pylori infection

Helicobacter pylori is a Gram-negative bacterium that infects over 50% of the world's population. This organism causes various gastric diseases such as chronic gastritis, peptic ulcer, and gastric cancer. H. pylori possesses lipopolysaccharides that share structural similarity to Lewis blood group antigens in gastric mucosa. Such antigenic mimicry could result in immune tolerance against antigens of this pathogen. On the other hand, H. pylori colonizes gastric mucosa by utilizing adhesins that bind Lewis blood group antigen-related carbohydrates expressed on gastric epithelial cells. After colonization, H. pylori induces acute inflammatory responses mainly by neutrophils. This acute phase is gradually replaced by a chronic inflammatory response. In chronic gastritis, lymphocytes infiltrate the lamina propria, and such infiltration is facilitated by the interaction between L-selectin on lymphocytes and peripheral lymph node addressin (PNAd), which contains 6-sulfo sialyl Lewis X-capped O-glycans, on high endothelial venule (HEV)-like vessels. H. pylori barely colonizes gland mucous cell-derived mucin where alpha1,4-GlcNAc-capped O-glycans exist. In vitro experiments show that alpha1,4-GlcNAc-capped O-glycans function as a natural antibiotic to inhibit H. pylori growth. These findings show that distinct sets of carbohydrates expressed in the stomach are closely associated with pathogenesis and prevention of H. pylori-related diseases, providing therapeutic potentialities based on specific carbohydrate modulation.

Carbohydrate-dependent defense mechanisms against Helicobacter pylori infection

Helicobacter pylori is a Gram-negative bacterium that infects over 50% of the world's population. This organism causes various gastric diseases such as chronic gastritis, peptic ulcer, and gastric cancer. H. pylori possesses lipopolysaccharide, which shares structural similarity to Lewis blood group antigens in gastric mucosa. Such antigenic mimicry could result in immune tolerance against antigens of this pathogen. On the other hand, H. pylori colonize gastric mucosa by utilizing adhesins, which bind Lewis blood group antigen-related carbohydrates expressed on gastric epithelial cells. In chronic gastritis, lymphocytes infiltrate the lamina propria, and such infiltration is facilitated by 6-sulfo sialyl Lewis X-capped O-glycans, peripheral lymph node addressin (PNAd), on high endothelial venule (HEV)-like vessels. The number of HEV-like vessels increases as chronic inflammation progresses. Furthermore, PNAd formed on HEV-like vessels disappear once H. pylori is eradicated. These results indicate that PNAd plays an important role in H. pylori-associated inflammation. H. pylori barely colonizes gland mucous cell-derived mucin where alpha1,4-GlcNAc-capped O-glycans exist. In vitro experiments show that alpha1,4-GlcNAc-capped O-glycans function as a natural antibiotic to inhibit H. pylori growth. We recently identified cholesterol alpha-glucosyltransferase (CHLalphaGcT) using an expression cloning strategy and showed that this enzyme is specifically inhibited by mucin-type O-glycans like those present in deeper portions of the gastric mucosa. These findings show that a battery of carbohydrates expressed in the stomach is closely associated with pathogenesis and also prevention of H. pylori-related diseases.

Asthma is inversely associated with Helicobacter pylori status in an urban population

Background

Microbial exposures have been suggested to confer protection from allergic disorders and reduced exposures to gastrointestinal microbiota have been proposed as an explanation for the increase in asthma prevalence. Since the general prevalence of Helicobacter pylori has been decreasing, we hypothesized that H. pylori serostatus would be inversely related to the presence of asthma.

Methods

Adults were recruited to participate in the New York University (NYU)/Bellevue Asthma Registry in New York City. Adult asthma cases (N = 318) and controls (N = 208) were identified and serum IgG antibodies to H. pylori whole cell antigens or the immunodominant CagA antigen were measured.

Results

As expected, the asthma cases and controls differed with respect to atopy and lung function. Seropositivity to H. pylori or CagA antigen was present in 47.1% of the total case and control study population. Asthma was inversely associated with CagA seropositivity (OR = 0.57, 95% CI = 0.36–0.89). Median age of onset of asthma (doctor's diagnosis) was older (21 years) among individuals with CagA+ strains than among H. pylori- individuals (11 years) (p = 0.006).

Conclusion

These data are consistent with the hypothesis that colonization with CagA+ H. pylori strains is inversely associated with asthma and is associated with an older age of asthma onset in an urban population. The data suggest H. pylori as a marker for protection.

Trial Registration

ClinicalTrials.gov NCT00212537

Role of ASC in the mouse model of Helicobacter pylori infection

Apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) is an adaptor molecule activating caspase-1 that stimulates pro-interleukin-1beta (pro-IL-1beta) and pro-IL-18, two pro-inflammatory cytokines with critical functions in host defense against a variety of pathogens. In this study, we investigated the role of ASC in the host defense against Helicobacter pylori utilizing ASC-deficient mice. Mice were orally inoculated with H. pylori; bacterial load, degree of gastritis, and mucosal levels of inflammatory cytokines were analyzed and compared with those obtained from wild-type mice. We found more prominent H. pylori colonization in ASC-deficient mice, as revealed by colony-forming unit counts. Both groups of mice developed gastritis; however, ASC-deficient mice showed significant attenuation of inflammation despite high H. pylori colonization. ELISA, immunohistochemistry, and quantitative RT-PCR analyses revealed complete suppression of IL-1beta and IL-18, and substantial reduction of interferon-gamma (IFN-gamma) expression, in ASC-deficient mice without apparent upregulation of other cytokines, including IL-10 and tumor necrosis factor-alpha. These results as a whole indicate that ASC exerts considerable influence on the host defense, acting through IL-1beta/IL-18 and subsequent IFN-gamma production, which in turn contributes to continuous chronic inflammatory response and consequent reduction of H. pylori colonization.

High diversity of vacA and cagA Helicobacter pylori genotypes in patients with and without gastric cancer

Background

Helicobacter pylori is associated with chronic gastritis, peptic ulcers, and gastric cancer. The aim of this study was to assess the topographical distribution of H. pylori in the stomach as well as the vacA and cagA genotypes in patients with and without gastric cancer.

Methodology/Principal Findings

Three gastric biopsies, from predetermined regions, were evaluated in 16 patients with gastric cancer and 14 patients with dyspeptic symptoms. From cancer patients, additional biopsy specimens were obtained from tumor centers and margins; among these samples, the presence of H. pylori vacA and cagA genotypes was evaluated. Positive H. pylori was 38% and 26% in biopsies obtained from the gastric cancer and non-cancer groups, respectively (p = 0.008), and 36% in tumor sites. In cancer patients, we found a preferential distribution of H. pylori in the fundus and corpus, whereas, in the non-cancer group, the distribution was uniform (p = 0.003). A majority of the biopsies were simultaneously cagA gene-positive and -negative. The fundus and corpus demonstrated a higher positivity rate for the cagA gene in the non-cancer group (p = 0.036). A mixture of cagA gene sizes was also significantly more frequent in this group (p = 0.003). Ninety-two percent of all the subjects showed more than one vacA gene genotype; s1b and m1 vacA genotypes were predominantly found in the gastric cancer group. The highest vacA-genotype signal-sequence diversity was found in the corpus and 5 cm from tumor margins.

Conclusion/Significance

High H. pylori colonization diversity, along with the cagA gene, was found predominantly in the fundus and corpus of patients with gastric cancer. The genotype diversity observed across systematic whole-organ and tumor sampling was remarkable. We find that there is insufficient evidence to support the association of one isolate with a specific disease, due to the multistrain nature of H. pylori infection shown in this work.

ERBBs in the gastrointestinal tract: recent progress and new perspectives

The gastrointestinal epithelium does much more than provide a physical barrier between the intestinal lumen and our internal milieu. It is actively engaged in absorption and secretion of salt and water via ion transporters, exchangers and selective ion channels. It is also a continuously self-renewing epithelium that undergoes ordered growth and differentiation along its vertical axis. From this dual perspective, we will consider the actions of the ERBB family of ligands and receptors in the maintenance of gastrointestinal homeostasis and discuss instances when the actions of this family go awry such as in cancer and Ménétrier's disease.

Gastric cancer among American Indians and Alaska Natives in the United States, 1999-2004

BACKGROUND

Gastric cancer incidence rates for American Indians and Alaska Natives (AI/ANs) historically have exceeded those for non-Hispanic whites (NHWs). Previous reports may have underestimated the true burden of gastric cancer in AI/AN populations because of misclassification of AI/AN race in cancer registries.

METHODS

Population-based cancer registry data from 1999 through 2004 were used to describe gastric cancer incidence in AI/ANs and NHWs in the US. To address misclassification of race, registry data were linked with Indian Health Service administrative records, and analyses were restricted to residents of Contract Health Service Delivery Areas (CHSDA). Disease patterns were assessed for 6 geographic regions and for all regions combined. Rates were expressed per 100,000 population and were age-adjusted to the 2000 US standard population.

RESULTS

In CHSDA counties, gastric cancer incidence rates for AI/ANs were higher than the rates for NHWs across most regions. For both sexes combined, AI/AN rates ranged from 6.1 in the East region to 24.5 in Alaska; there was relatively little regional variation in NHW rates. Most patients with gastric cancer were diagnosed with late-stage disease, regardless of race, age, or sex. In some regions, cancer rates in the central/distal portions of the stomach were higher among AI/ANs than among NHWs, whereas rates in the proximal stomach were similar between the 2 populations.

CONCLUSIONS

AI/ANs are generally at greater risk for gastric cancer than NHWs. Relatively high rates of cancer in the central/distal portions of the stomach among AI/ANs in some geographic regions may indicate a disproportional burden of Helicobacter pylori-associated disease.

Toll-like receptors and cytokines in immune responses to persistent mycobacterial and Salmonella infections

Bacterial persistence is of major concern worldwide in the control of a number of bacterial infections. The carriers who are asymptomatic act as reservoirs of the bacteria. Knowledge of the host response, of the persistence process, and of the potential of biological mediators as diagnostic markers is essential towards development of prophylactic and treatment modalities for these diseases. Immune mechanisms related to recognition and elimination of the bacteria play pivotal roles in the control of bacterial infections. The majority of the studies on bacterial infections detail the immune mechanisms in the active phase of infection, and reports on the immune status in carriers are scanty. The present review describes the role of recognition molecules (TLRs) and the immune mediators (cytokines) in bacterial persistence. It appears that the TLR-mediated induction of cytokine profiles differs in active infection and bacterial persistence, with an active Th1 response being beneficial for the clearance of a high load of bacteria and at the same time conducive for the persistence of low bacterial load. Immunomodulation aiming at stimulation of the immune responses should be carried out with care as it could give rise to a carrier state in individuals with low load of the bacteria.

DNA-level diversity and relatedness of Helicobacter pylori strains in shantytown families in Peru and transmission in a developing-country setting

The efficiency of transmission of a pathogen within families compared with that between unrelated persons can affect both the strategies needed to control or eradicate infection and how the pathogen evolves. In industrialized countries, most cases of transmission of the gastric pathogen Helicobacter pylori seems to be from mother to child. An alternative model, potentially applicable among the very poor in developing countries, where infection is more common and the sanitary infrastructure is often deficient, invokes frequent transmission among unrelated persons, often via environmental sources. In the present study, we compared the genotypes of H. pylori from members of shantytown households in Peru to better understand the transmission of H. pylori in developing-country settings. H. pylori cultures and/or DNAs were obtained with informed consent by the string test (a minimally invasive alternative to endoscopy) from at least one child and one parent from each of 62 families. The random amplified polymorphic DNA fingerprints of 57 of 81 (70%) child-mother strain pairs did not match, nor did the diagnostic gene sequences (>1% DNA sequence difference), independent of the child's age (range, 1 to 39 years). Most strains from siblings or other paired family members were also unrelated. These results suggest that H. pylori infections are often community acquired in the society studied. Transmission between unrelated persons should facilitate the formation of novel recombinant genotypes by interstrain DNA transfer and selection for genotypes that are well suited for individual hosts. It also implies that the effective prevention of H. pylori infection and associated gastroduodenal disease will require anti-H. pylori measures to be applied communitywide.

The role of viral and bacterial pathogens in gastrointestinal cancer

The association of Helicobacter pylori (H. pylori) with gastric cancer is thus far the best understood model to comprehend the causal relationship between a microbial pathogen and cancer in the human gastrointestinal tract. Besides H. pylori, a variety of other pathogens are now being recognized as potential carcinogens in different settings of human cancer. In this context, viral causes of human cancers are central to the issue since these account for 10-20% of cancers worldwide. In the case of H. pylori and gastric cancer, as well as the human papillomavirus and anal cancer, the causal relationship between the infectious agent and the related cancer in the gastrointestinal tract has been clearly confirmed by epidemiological and experimental studies. Similarly, Epstein-Barr virus and the oncogenic JC virus are being suggested as possible causative agents for cancers in the upper and lower gastrointestinal tract. This review discusses various viral and microbial pathogens and their oncogenic properties in the evolution of gastrointestinal carcinogenesis and summarizes the available experimental data make a convincing agreement favoring the associations between infectious agents and specific human cancers.

Changes in the presence of urine Helicobacter pylori antibody in Japanese children in three different age groups

BACKGROUND

The rates of acquisition and spontaneous eradication of Helicobacter pylori infection in children has yet to be established. To determine these rates in children living in an urban region of Japan, the levels of urine H. pylori antibodies in children of three different age groups were measured.

METHODS

A urine-based enzyme-linked immunosorbent assay (ELISA) was used to detect H. pylori antibodies twice within a 12 month interval over 2 years in 452 healthy children living in Tokyo. The subjects were divided into three groups: ages 4, 7, and 10 years.

RESULTS

The prevalence of H. pylori infection was not different among the groups, being between 4.0% and 6.7%. The rate of turn to positivity for H. pylori infection was 1.5% per year and the rate of turn to negativity was 1.1%, but in the 10 year age group the rates were markedly lower than in the younger children.

CONCLUSION

The prevalence of H. pylori infection in Tokyo was 4.0-6.7% and was not different among 4, 7, and 10 year age groups.

Endoscopic diagnoses and CLO test results in 9239 cases, prevalence of Helicobacter pylori in Istanbul, Turkey

BACKGROUND

Helicobacter pylori is implicated in the etiology of gastric and duodenal ulcer, non-ulcer dispepsia, atrophic gastritis, gastric adenocarcinoma and lymphoma.

METHODS

Between November 1995 and December 2004, the presence of H. pylori was investigated using the CLO test in 9239 patients who underwent upper gastrointestinal endoscopy at a single institution in Istanbul, Turkey. The results were evaluated as early-late positive, and negative.

RESULTS

There were 4667 women (50.51%) with a mean age of 44.5 years (range, 13-90 years), and 4572 men (49.49%) with a mean age of 45.7 years (range, 11-85 years). The CLO test was positive in 41.44% of cases. The most frequent symptoms on admission were epigastric pain (46.2%) and burning (19.6%). The most frequent endoscopic diagnosis was pangastritis (64%) and non-erosive duodenitis (30.5%). The H. pylori positivity was 61.53% during the first 5-year period and 38.47% during the second 5-year period. The H. pylori positivity was significant in patients using non-steroidal anti-inflamatory drugs and tobacco (P < 0.001).

DISCUSSION AND CONCLUSION

Helicbacter pylori prevelance remains an important health problem for Turkey although it has diminished in parallel to the national development during the last years. Helicbacter pylori, as a first-degree carcinogen, should be investigated and eradicated particularly in high-risk patients.

Changing trends in gastrointestinal disease in the Asia-Pacific region

The new millennium has seen distinct changes in the pattern of gastrointestinal disease in the Asia-Pacific region. These changes are important as more than half of the world's population come from the region and therefore impact significantly on the global disease burden. The highest incidence of gastric cancer (GCA) has been reported from Asia and GCA remains a very important cancer. However time-trend studies have shown a decrease in GCA incidence in several countries in Asia. A rise in cardio-esophageal cancers as seen in the West has not been reported. On the other hand, colorectal cancer has been steadily increasing in Asia with age-standardized incidence rates of some countries approaching that of the West. The pattern of acid-related diseases has also changed. Gastroesophageal reflux disease is a fast emerging disease with an increasing prevalence of reflux esophagitis and reflux symptoms. The prevalence of peptic ulcer disease has at the same time declined in step with a decrease in H. pylori infection. Many of the changes taking place mirror the Western experience of several decades ago. Astute observation of the epidemiology of emerging diseases combined with good scientific work will allow a clearer understanding of the key processes underlying these changes. With rapid modernization, lifestyle changes have been blamed for an increase in several diseases including gastroesophageal reflux disease, nonalcoholic fatty liver disease and colorectal cancer. A worrying trend has been the increase in obesity among Asians, which has been associated with an increase in metabolic diseases and various gastrointestinal cancers. Conversely, an improvement in living conditions has been closely linked to the decrease in GCA and H. pylori prevalence.

American College of Gastroenterology guideline on the management of Helicobacter pylori infection

Helicobacter pylori (H. pylori) remains a prevalent, worldwide, chronic infection. Though the prevalence of this infection appears to be decreasing in many parts of the world, H. pylori remains an important factor linked to the development of peptic ulcer disease, gastric malignanc and dyspeptic symptoms. Whether to test for H. pylori in patients with functional dyspepsia, gastroesophageal reflux disease (GERD), patients taking nonsteroidal antiinflammatory drugs, with iron deficiency anemia, or who are at greater risk of developing gastric cancer remains controversial. H. pylori can be diagnosed by endoscopic or nonendoscopic methods. A variety of factors including the need for endoscopy, pretest probability of infection, local availability, and an understanding of the performance characteristics and cost of the individual tests influences choice of evaluation in a given patient. Testing to prove eradication should be performed in patients who receive treatment of H. pylori for peptic ulcer disease, individuals with persistent dyspeptic symptoms despite the test-and-treat strategy, those with H. pylori-associated MALT lymphoma, and individuals who have undergone resection of early gastric cancer. Recent studies suggest that eradication rates achieved by first-line treatment with a proton pump inhibitor (PPI), clarithromycin, and amoxicillin have decreased to 70-85%, in part due to increasing clarithromycin resistance. Eradication rates may also be lower with 7 versus 14-day regimens. Bismuth-containing quadruple regimens for 7-14 days are another first-line treatment option. Sequential therapy for 10 days has shown promise in Europe but requires validation in North America. The most commonly used salvage regimen in patients with persistent H. pylori is bismuth quadruple therapy. Recent data suggest that a PPI, levofloxacin, and amoxicillin for 10 days is more effective and better tolerated than bismuth quadruple therapy for persistent H. pylori infection, though this needs to be validated in the United States.

Prevalence of Helicobacter pylori infection among Egyptian children: impact of social background and effect on growth

OBJECTIVE

The study aim was to assess the prevalence of Helicobacter pylori infection in Egyptian schoolchildren and its effect on growth parameters.

DESIGN

A cross-sectional population-based study was conducted among 286 schoolchildren (168 boys and 118 girls), with a mean age of 11.04 +/- 0.19 years, to determine the prevalence of H. pylori. The presence of the bacterium was assessed using the [13C]urea breath test. Relevant personal and socio-economic data on risk factors for infection were collected. Height and weight were analysed in relation to H. pylori infection.

RESULTS

The overall prevalence of H. pylori infection was 72.38%. Attending school in a socially deprived area and residing in an overcrowded home were the major risk factors for infection. Differences between infected and non-infected children were significant with regard to body weight and height (weight: 39.5 +/- 1.0 vs. 44.6 +/- 1.8 kg, P = 0.05; height: 139.9 +/- 1.3 vs. 144.2 +/- 2.1 cm; P = 0.009). The number of children (both boys and girls) falling below the 5th percentile of height-for-age was significantly higher in infected than non-infected children (P = 001), similarly for Z-scores for height-for-age below -2.0 (P = 0.003).

CONCLUSION

The results demonstrate not only that the prevalence of H. pylori infection is extremely high among Egyptian schoolchildren, but also that the adverse effects of the infection reach far beyond the stomach. Evidence of the burden of infection on growth failure is presented.

Decreasing prevalence combined with increasing eradication of Helicobacter pylori infection in the United States has not resulted in fewer hospital admissions for peptic ulcer disease-related complications

BACKGROUND

Helicobacter pylori infection is a major cause of peptic ulcer disease, but the prevalence of this infection has been decreasing steadily. Additionally, eradication of H. pylori decreases ulcer recurrence and prevents ulcer complications such as bleeding.

AIM

To examine whether the decreased prevalence of H. pylori and increased use of eradication regimens have affected the prevalence of peptic ulcer disease-related hospitalizations.

METHODS

We chose to study a period between 1996 and 2005. The number of gastric and duodenal ulcers as primary or secondary hospital discharge diagnoses per year for the 10-year span was collected from five large US hospitals. Collected data were analysed using Spearman correlation.

RESULTS

No statistically significant trend was observed in the number of gastric or duodenal ulcers listed as primary or secondary discharge diagnoses at any of the five healthcare centres.

CONCLUSIONS

Despite a decreasing prevalence of H. pylori and the increasing use of successful H. pylori eradication regimens, the prevalence of peptic ulcer disease and its complications has not changed. In the US other aetiologies, including non-steroidal anti-inflammatory drugs, may be playing a larger role than once thought.

Resistance rate to antibiotics of Helicobacter pylori isolates in eastern Taiwan

BACKGROUND AND AIM

Prevalence of Helicobacter pylori (H. pylori) strains resistant to metronidazole, clarithromycin and amoxicillin is increasing worldwide. The aim of this study was to determine the antibiotic susceptibility patterns in H. pylori strains isolated from eastern Taiwan.

METHODS

One strain each of H. pylori was isolated from 133 symptomatic patients and subjected to determination of the minimal inhibitory concentration (MIC) by the Epsilometer test (E-test) for four antibiotics commonly used in the treatment of H. pylori infections.

RESULTS

None of the strains were resistant to tetracycline. Resistance to metronidazole (8 microg/mL), clarithromycin (1 microg/mL) and amoxicillin (8 microg/mL) was found in 51.9%, 13.5% and 36.1% of the isolates, respectively. Metronidazole-resistant strains were isolated more frequently from women (49/78; 62.8%) than from men (20/55; 36.4%). Resistance to at least two antimicrobial agents was detected in 33.8% of the isolates. There was a high rate of resistance to both metronidazole and amoxicillin (18.1%).

CONCLUSIONS

Clarithromycin and tetracycline may provide useful components of treatment regimens in eastern Taiwan. In addition, pretreatment microbial susceptibility testing rather than empiric therapy is highly recommended for eradication of H. pylori infection.

Decreasing seroprevalence of Helicobacter pylori infection during 1993-2003 in Guangzhou, southern China

BACKGROUND

Prevalence of Helicobacter pylori infection is inversely associated with socioeconomic conditions. The aim of the study was to evaluate changes in the seroprevalence of H. pylori infection during 1993-2003 in Guangzhou, a representative city of southern China with quick improvement in socioeconomy.

METHODS

From March to August 2003, sera were collected from 1471 healthy persons (760 male and 711 female subjects, aged 3-92 years) undergoing annual routine health examination in Guangzhou. H. pylori infection was checked by enzyme-linked immunosorbent assay (ELISA).

RESULTS

In 2003, the overall prevalence rate of H. pylori infection was 47% with no gender difference (p > .05). Children aged 1-5 years had the prevalence rate of 19.4%. The prevalence rate then increased steadily with annual infection rate of approximately 1% after this age, reaching a plateau of approximately 55% after the age of 50 years. The peak seroprevalence rate was 63.2% at 40-50 years. Comparing the prevalence rate of H. pylori infection in 2003 with data obtained in 1993, statistically significant decrease of H. pylori infection rate ranged from 11.4 to 18.0% in different age groups was found. The overall age-standardized H. pylori seroprevalence rate was 62.5% in 1993 and 49.3% in 2003. The seroprevalence of H. pylori was found to be significantly decreased over a time span of 10 years (p < .001).

CONCLUSIONS

Our data suggest that the seroprevalence of H. pylori infection has significantly decreased during the 10-year period in Guangzhou. This change may be attributable to the improvement in socioeconomic conditions in this city.

The transmission of Helicobacter pylori: the effects of analysis method and study population on inference

Although much is known about the virulence of Helicobacter pylori, the transmission pathways for this bacterium are still unresolved. Transmission has been addressed through: (1) prevalence within families; (2) detection in fecal/oral environments; (3) detection in the abiotic/biotic environment; and (4) direct inference from strain similarity. Here, we review the molecular and biochemical methods used and discuss the relative merits of each. Furthermore, as there are differences between developing and developed nations, we discuss the results obtained from transmission studies in light of the study population. We conclude that H. pylori is probably transmitted person-to-person, facilitated by fecal-oral transmission during episodes of diarrhea or gastro-oral contact during periods of vomiting. The persistence of H. pylori in abiotic and biotic environments remains unproven but possible reactivation from viable, non-culturable coccoid forms should be further investigated. Finally, we speculate on the effect of host-pathogen interactions in confounding the inference of transmission.

Rapid detection of clarithromycin-resistant Helicobacter pylori in patients with dyspepsia by fluorescent in situ hybridization (FISH) compared with the E-test

BACKGROUND

Clarithromycin is the antibiotic of choice for treatment of H.pylori-related dyspepsia, but unfortunately, resistance to clarithromycin is not rare. Detection of resistant strains takes 2 to 4 days by conventional methods. In this report, we applied the FISH technique for rapid detection of H.pylori in biopsies of dyspeptic patients.

METHODS

Gastric biopsies from 50 patients suffering from dyspepsia were tested in this study. Part of each biopsy specimen was cultured and the remainder was fixed in liquid nitrogen. After mounting of frozen sections on microscopic slides, they were hybridized with oligonucleotide probes for detection of clarithromycin-resistant H.pylori. The slides were visualized under a fluorescent microscope. Susceptibility of cultured strains of H. pylori to clarithromycin was also determined by the E-test and the results were compared.

RESULTS

Twenty-five of 50 biopsy specimens examined by FISH were positive for H.pylori. FISH showed that 17 strains (68%) were susceptible to clarithromycin and 6 strains (24%) were resistant. Bacteria isolated following culture of 2 biopsy specimens had a mixture of both clarithromycin-susceptible and resistant strains (8%). There was no discrepancy between the E-test and FISH technique for detection of resistant strains of H.pylori.

CONCLUSION

FISH is a rapid technique for detection of H.pylori in clinical samples. Moreover, strains susceptible to clarithromycin can be detected quickly. Therefore, this method is suitable for determination of susceptibility of H.pylori to clarithromycin, especially when a quick decision is necessary for treating dyspeptic patients.

Low concentrations of zinc in gastric mucosa are associated with increased severity of Helicobacter pylori-induced inflammation

BACKGROUND

Chronic Helicobacter pylori infection is the most common cause of gastric cancer. H. pylori induces oxidative stress while zinc deficiency results in increased sensitivity to it. In Ecuador, the prevalence of gastric cancer and zinc deficiency are high. We hypothesized that zinc deficiency in Ecuadorian people would cause increased H. pylori-induced inflammation in the gastric mucosa associated with lower tissue zinc concentrations.

METHODS

Three hundred and fifty-two patients with dyspepsia underwent endoscopy to obtain gastric mucosa biopsies. Diagnosis of H. pylori infection and its severity, histopathology, mucosal zinc concentration, and inflammation intensity were determined.

RESULTS

H. pylori-infected patients with non-atrophic chronic gastritis had lower concentrations of zinc in gastric mucosa than uninfected patients with the same type of gastritis (251.3 +/- 225.3 vs. 426.2 +/- 279.9 ng/mg of protein; p = .016). Considering all patients, the more severe the H. pylori infection, the higher the percentage of subjects with infiltration by polymorphonuclear (PMN) cells (p = .0001). Patients with high PMN infiltration had lower mucosal zinc concentrations than patients with low PMN infiltration (35.2 +/- 20.7 vs. 242.9 +/- 191.8 ng/mg of protein; p = .021).

CONCLUSIONS

The degree of inflammation in H. pylori-induced gastritis appears to be modulated by gastric tissue zinc concentrations.

Trends in management and outcomes of acute nonvariceal upper gastrointestinal bleeding: 1993-2003

BACKGROUND & AIMS

ANVUGIB is a common reason for hospital admission and has been traditionally associated with a mortality rate of 5%-10%. There have been numerous innovations in the prevention and management of ANVUGIB in recent years, although the effect of these innovations on ANVUGIB incidence and outcomes is unknown.

METHODS

We used the Statistics Canada's Health Person Oriented Information Database [corrected], which contains data characterizing every inpatient hospital admission in Canada between 1993 and 2003. We identified admissions consistent with nonvariceal upper gastrointestinal bleeding using both a broad and narrow ICD-9/ICD-10-based definition. Data were extracted concerning patient demographics, incidence of surgery for complications of upper gastrointestinal bleeding, and overall mortality.

RESULTS

Between 1993 and 2003, ANVUGIB incidence decreased from 77.1 cases to 53.2 per 100,000/y for the broad definition, and from 52.4 to 34.3 cases per 100,000/y for the narrow definition. ANVUGIB incidence rose slightly in 2000, coincident with the introduction of COX-2 inhibitors. The proportion of ANVUGIB subjects requiring surgical intervention declined over the 10 years from 7.1% to 4.5%, although the rate of decline did not increase after the introduction of intravenous proton pump inhibitors (IV PPIs). The mortality rate remained steady at approximately 3.5%.

CONCLUSIONS

The incidence of ANVUGIB and the need for operative intervention has been steadily declining since 1993. ANVUGIB-associated mortality remained constant, although at a rate lower than traditionally reported. The impact of IV PPIs on mortality and operative intervention on a population-wide basis is likely minimal.

Mechanisms of Disease: Helicobacter pylori-related gastric carcinogenesis—implications for chemoprevention

Gastric adenocarcinoma is the second most common cause of cancer-related mortality worldwide. Infection with Helicobacter pylori is the single most common cause of adenocarcinoma of the distal stomach. Cancer risk is believed to be related to differences among H. pylori strains and inflammatory responses governed by host genetics. In particular, specific interactions between host factors that modulate the response to the infection, and bacterial virulence factors that can directly cause tissue damage seem to have a major pathogenic role in the development of gastric cancer. In addition, environmental factors can modify key growth signaling pathways within the gastric mucosa, which leads to the alteration of epithelial cell growth. Preventive strategies represent the most promising means of decreasing cancer risk, and must be aimed at the control of H. pylori infection, improvement of environmental conditions, and the identification of subjects who are genetically predisposed to the development of cancer in response to H. pylori infection. Understanding the intracellular signaling pathways that are specifically affected by H. pylori and that promote phenotypic and genotypic changes that might ultimately progress to malignant transformation could enable physicians to focus eradication therapy appropriately and design interventions targeted at the molecular level to prevent the development of gastric cancer.

A population genetics pedigree perspective on the transmission of Helicobacter pylori

The inference of transmission pathways for medicinally important bacteria is important to our understanding of pathogens. Here we report analyses of transmission in Helicobacter pylori, a major carcinogen. Our study is novel in that the focal community comprises detailed family pedigrees and has a high prevalence of H. pylori. To infer transmission, we performed high-resolution analyses of nucleotide sequences for three genes and accounted for the occurrence of mutation and recombination through the use of simulation modeling. Our results demonstrate that transmission has a strong nonfamilial component potentially the result of a large proportion of infections derived from the community. These results are interesting from both a medical and an evolutionary standpoint. First, efficient control measures and beliefs about the sources of H. pylori infection should be reevaluated. Evolutionarily, our results contradict the hypothesis of strict vertical transmission, presented as an explanation for the strong correlation between human population history and H. pylori diversity. Thus the paradox of persistent phylogenetic structure, despite a permissive mode of transmission and high recombination rates, must be solved elsewhere. Here we consider the potential for recombination events to maintain genetic structure in light of horizontal transmission.

Impact of Helicobacter pylori on the management of dyspepsia in primary care

BACKGROUND

It is unclear what impact Helicobacter pylori infection has had on the management of dyspepsia in primary care and to what extent published guidelines on H. pylori are implemented in routine clinical practice.

AIM

To assess the impact of H. pylori infection on the management of dyspepsia in primary care.

METHODS

Patients referred by primary care doctors to an open-access 13-carbon urea breath test service over a 2-year period for their first urea breath test were included in the study. Individual breath results were linked with data on prescribing obtained from the General Medical Services prescription database.

RESULTS

Of 805 patients, 374 (47%) had a positive urea breath test and 431 (54%) a negative urea breath test. Of positive urea breath test patients, only 245 (64%) were prescribed eradication therapy in the 3 months after the breath test and only 43% were referred back for re-testing. In the year after the urea breath test, there was a significant fall in prescribing of antisecretory therapy which was greatest in the patients who received H. pylori therapy (P < 0.001).

CONCLUSIONS

There appears to be under and inappropriate treatment of H. pylori infection in primary care, and a low rate of re-testing after eradication, indicating that current guidelines are not well implemented in practice.