Is there seasonal periodicity in the prevalence of Helicobacter pylori?

The objective of the present study was to evaluate seasonal periodicity in the prevalence of Helicobacter pylori. A prospective study was performed on 1076 consecutive patients who were investigated in our hospital over a 3-year span because of epigastric complaints. Our findings indicate a significant accumulation of positive Helicobacter pylori tests in October. Gastric acidity, gender, and age did not influence Helicobacter pylori infection significantly. There was no significant correlation between potential seasonal influence on the diagnosis of ulcer disease and the seasonal fluctuation of Helicobacter pylori infection. The seasonality was confirmed by cosinor analysis for the absolute frequencies of H. pylori infections and also for the number of cases positive for H. pylori per number of presenting patients per month. A seasonal concept of a sensitivity threshold for positive Helicobacter pylori testing is introduced, taking into account such factors as immune system, nutrition, and medication status.     

Is Helicobacter pylori a True Microaerophile?

BACKGROUND: There is no general consensus about the specific oxygen and carbon dioxide requirements of the human pathogen Helicobacter pylori. This bacterium is considered a microaerophile and consequently, it is grown under atmospheres at oxygen tensions 5-19% and carbon dioxide tensions 5-10%, both for clinical and basic and applied research purposes. The current study compared the growth of H. pylori in vitro, under various gas atmospheres, and determined some specific changes in the physiology of bacteria grown under different oxygen partial pressures. METHODS: Measurements of bacterial growth under various conditions were carried out employing classical solid and liquid culture techniques. Enzymatic activities were measured using spectrophotometric assays. RESULTS: H. pylori and all the other Helicobacter spp. tested had an absolute requirement for elevated carbon dioxide concentrations in the growth atmosphere. In contrast with other Helicobacter spp., H. pylori can tolerate elevated oxygen tensions when grown at high bacterial concentrations. Under 5% CO(2), the bacterium showed similar growth in liquid cultures under oxygen tensions from microaerobic (< 5%) to fully aerobic (21%) at cell densities higher than 5 x 10(5) cfu/ml for media supplemented with horse serum and 5 x 10(7) cfu/ml for media supplemented with beta-cyclodextrin. Evidence that changes occurred in the physiology of H. pylori was obtained by comparing the activities of ferredoxin:NADH (nicotinamide adenine dinucleotide) oxidoreductases of bacteria grown under microaerobic and aerobic atmospheres. CONCLUSIONS: H. pylori is a capnophile able to grow equally well in vitro under microaerobic or aerobic conditions at high bacterial concentrations, and behaved like oxygen-sensitive microaerophiles at low cell densities. Some characteristics of H. pylori cells grown in vitro under microaerobic conditions appeared to mimic better the physiology of organisms grown in their natural niche in the human stomach.     

Is Helicobacter pylori associated with non-ulcer dyspepsia and will eradication improve symptoms? A meta-analysis

ObjectivesTo examine the association between Helicobacter pylori infection and non-ulcer dyspepsia, and to assess the effect of eradicating H pylori on dyspeptic symptoms in patients with non-ulcer dyspepsia.DesignSystematic review and meta-analysis of (a) observational studies examining the association between Helicobacter pylori infection and non-ulcer dyspepsia (association studies), and (b) therapeutic trials examining the association between eradication of H pylori and dyspeptic symptoms in patients with non-ulcer dyspepsia (eradication trials).Results23 association studies and 5 eradication trials met the inclusion criteria. In the association studies the summary odds ratio for H pylori infection in patients with non-ulcer dyspepsia was 1.6 (95% confidence interval 1.4 to 1.8). In the eradication trials the summary odds ratio for improvement in dyspeptic symptoms in patients with non-ulcer dyspepsia in whom H pylori was eradicated was 1.9 (1.3 to 2.6).ConclusionsSome evidence shows an association between H pylori infection and dyspeptic symptoms in patients referred to gastroenterologists. An improvement in dyspeptic symptoms occurred among patients with non-ulcer dyspepsia in whom H pylori was eradicated.     

Is Antrum or Corpus the Best Site for Culture of Helicobacter pylori?

Background Isolating Helicobacter pylori on culture media and performing antibiotic susceptibility testing is potentially the most useful tool for guiding antibiotic therapy, especially when antimicrobial resistance is suspected. The aim of this study was to determine whether the yield of H. pylori culture was related to the site from which the gastric specimen was obtained either before or after therapy.
Methods. Gastric mucosal biopsies from the antrum and the corpus of the stomach were cultured. H. pylori status was determined by histological assessment using the Genta stain.
Results. Fifty-two patients with documented H. pylori infection were studied: Twenty-three were tested before antibiotic therapy and 29 after therapy had failed. In 47 patients (90%), both antral and corpus culture specimens were positive. In 5 patients (10%), only one site was positive, with three false-negative antral and two false negative corpus cultures. The overall sensitivity of culture in detecting H. pylori infection was 95% (95% confidence interval = 89–98%) and was not significantly different for the antrum or corpus, either before or after therapy.
Conclusion. Culture of gastric biopsies from either the antrum or the corpus has an excellent diagnostic yield even in patients who failed antimicrobial therapy.     

Does Helicobacter pylori cause gastric cancer via oxidative stress?

Epidemiologic evidence strongly supports a causal role for Helicobacter pylori in gastric carcinogenesis. The infection was recognized as a Class I human carcinogen by the International Agency for Research on Cancer in 1994. The bacterium does not induce carcinogenesis by itself. The present scientific consensus is that the bacterial oncogenic role is mediated by the chronic active inflammation it elicits in the gastric mucosa. Although the ultimate basic mechanism of carcinogenesis is unknown, strongly suggestive evidence points to oxidative stress as having a pivotal role in the process. This review discusses some of the evidence accumulated so far to support such a role. Numerous avenues of research are open and represent an intriguing challenge to the scientific community.     

Is inflammation the cause of pre-eclampsia?

It has been proposed that either excessive inflammation or an imbalance in angiogenic factors cause pre-eclampsia. In the present review, the arguments for and against the role of inflammation and/or angiogenic imbalance as the cause of pre-eclampsia are discussed on the basis of the Bradford-Hill criteria for disease causation. Although both angiogenic imbalance and systemic inflammation are implicated in pre-eclampsia, the absence of temporality of inflammatory markers with pre-eclampsia challenges the concept that excessive inflammation is the cause of pre-eclampsia. In contrast, the elevation of anti-angiogenic factors that precede the clinical signs of pre-eclampsia fulfils the criterion of temporality. The second most important criterion is the dose-response relationship. Although such a relationship has not been proven between pro-inflammatory cytokines and pre-eclampsia, high levels of anti-angiogenic factors have been shown to correlate with increased incidence and disease severity, hence satisfying this condition. Finally, as the removal of circulating sFlt-1 (soluble Fms-like tyrosine kinase receptor-1) from pre-eclamptic patients significantly improves the clinical outcome, it fulfils the Hill's experiment principle, which states that removal of the cause by an appropriate experimental regimen should ameliorate the condition. In contrast, treatment with high doses of corticosteroid fails to improve maternal outcome in pre-eclampsia, despite suppressing inflammation. Inflammation may enhance the pathology induced by the imbalance in the angiogenic factors, but does not by itself cause pre-eclampsia. Development of therapies based on the angiogenic and cytoprotective mechanisms seems more promising.     

Is the Association Between Helicobacter pylori Infection and Anemia Age Dependent?

Background: The relationship between H. pylori infection and anemia in childhood is still unclear. The aim of the study was to examine the association between H. pylori infection and anemia or iron deficiency in school‐age children and in infants. Materials and Methods: Six‐ to 9‐ year‐old Israeli Arab children (N = 202) and infants (N = 197) were examined for hemoglobin and ferritin levels. ELISA was used to detect H. pylori antigens in stool specimens collected from the participants. Household characteristics were obtained through personal interviews with the mothers. Results: The prevalence of anemia was 15.5 versus 5.5% in H. pylori‐positive and ‐negative school‐age children, respectively and 34.5 versus 29.8% in H. pylori‐positive and ‐negative infants, respectively. The Mantel–Haenszel age‐adjusted prevalence ratio (PR) and 95% confidence intervals (CIs) were 1.6 (95%CI 1.0, 2.6). In multivariate analysis controlling for socioeconomic variables, H. pylori infection was associated with 2.8 higher prevalence of anemia only in school‐age children: adjusted PR 2.8 (95% CI 0.9, 9.3). The adjusted mean difference in hemoglobin levels between H. pylori infected school‐age children and uninfected ones was ?0.372 gr/dL (95% CI ?0.704, ?0.039) (p = .04). The respective mean ferritin difference was ?6.74 μg/L (95% CI ?13.38, ?.011) (p = .04). Such differences were not found in infants. Conclusions: H. pylori infection is associated with higher prevalence of anemia in school‐age children independently of socioeconomic variables. Such association was not observed in infants. These findings are of clinical and public health importance.     

Is There a Benefit to Extending the Duration of Helicobacter pylori Sequential Therapy to 14 Days?

Background and Aims: Ten‐day sequential therapy with a proton‐pump inhibitor (PPI) and amoxicillin followed by a PPI, clarithromycin, and an imidazole typically achieves Helicobacter pylori (H. pylori) eradication rates between 90 and 94% (i.e., Grade B success). It has been suggested that prolonging the duration of therapy might improve the treatment success. We tested whether prolonging treatment duration to 14‐days would improve the results to 95% or greater eradication. Methods: This was a multi‐center, single site, pilot study in which H. pylori‐infected patients received a 14‐day sequential therapy (esomeprazole and amoxicillin for 7 days followed by esomeprazole, clarithromycin, and metronidazole for 7 days). H. pylori status was assessed 8 weeks after therapy. Success was defined as achieving 95% or greater eradication by per‐protocol (PP) analysis. Results: One hundred and twenty‐three subjects received the 14‐day sequential therapy. The eradication rate was 93.9% (95% confidence interval [CI], 89.5–98.3%) by PP and 91.9% (95% CI, 87.1–96.7%) by intention‐to‐treat analysis. Adverse events were experienced by 21.1%; compliance of 90% or greater was 95.9%. Conclusions: Extending sequential therapy to 14 days did not result in improving the treatment outcome to 95% or greater.     

Genetic factors in the development of gastric precancerous lesions--a role of Helicobacter pylori ?

Helicobacter pylori is believed to predispose to gastric cancer by inducing gastric precancerous alterations. There is a well known predisposition to gastric cancer and the risk of developing it is greater in relatives of patients with familial cases of this malignancy. The aim of this study was to determine the prevalence of gastric precancerous lesions (atrophy and intestinal metaplasia) and their association with Hp infection in first-degree relatives in patients with noncardia gastric cancer. METHODS: Hp status and gastric histology assessed by upper gastrointestinal endoscopy, biopsies from the antral and body region, the rapid urease test and staining for Hp, inflammation, activity, atrophy and intestinal metaplasia (prevalence and grading) were studied in 108 first-degree relatives of patients with noncardia gastric cancer and compared with 73 controls with mild non-ulcer dyspepsia who had no cancer relatives and were examined in the same way. RESULTS: subjects with and without cancer relatives had a similar prevalence of Hp infection (49 vs. 47%). Endoscopy revealed a few asymptomatic duodenal ulcers and small hiatus hernias in Hp positive subjects of both groups. Hp positive relatives of gastric cancer had a markedly higher prevalence of atrophy than those with Hp negativity without cancer relatives (29 vs. 9%) and those with Hp negativity and cancer relatives (29 vs. 3%. Prevalence of intestinal metaplasia was also higher in those with Hp positivity and cancer relatives than in those without cancer relatives (15 vs. 5% and was not present in Hp negative subjects with cancer relatives. Inflammation and activity showed similar scores in subjects with and without cancer relatives with higher scores in both Hp positive groups. The prevalence of precancerous lesions in the relatives of gastric cancer was nearly always confined to those with Hp positivity. One year after eradication the prevalence of atrophy in cancer relatives decreased from 29 to 14%; prevalence of intestinal metaplasia remained without substantial changes. Scores for inflammation and activity were also lower after eradication. CONCLUSIONS: First-degree relatives of patients with gastric cancer have an increased prevalence of gastric precancerous abnormalities which are strongly confined to those with Hp infection. Eradication of Hp in these subjects with cancer relatives reduces the prevalence of precancerous lesions (atrophy) and grades of inflammation and activity. In view of these results, eradication of Hp should be offered to such subjects.