The effect of omeprazole dosing on the isolation of Helicobacter pylori from gastric aspirates

An African perspective on Helicobacter pylori: prevalence of human infection, drug resistance, and alternative approaches to treatment

Helicobacter pylori is a Gram-negative, micro-aerophilic, motile, curved rod that inhabits the gastric mucosa of the human stomach. It chronically infects thousands of millions of people world-wide, and is one of the most genetically diverse of bacterial species. Infection with the bacterium leads to chronic gastritis, peptic ulceration, gastric cancers and gastric mucosa-associated lymphoid-tissue (MALT) lymphoma. The prevalence of infection appears to be partly determined by geographical and socio-demographic factors, being higher in Africa than elsewhere. Current treatment, based on potent combinations that each consist of a proton-pump inhibitor and two antibiotics, is successful in 80%-90% of patients. Some undesirable side-effects, poor patient compliance and drug resistance are, however, associated with significant levels of treatment failure and with contra-indications for some patients. Antibiotic resistance in H. pylori is a growing global concern that merits the urgent attention of public-health authorities. Numerous pieces of clinical evidence have revealed that eradication of the organism from a patient results in improvement of gastritis and drastically decreases the frequency of relapse of gastric and duodenal ulcers. Natural products, including medicinal plants and honey, may offer useful alternatives in the treatment of H. pylori-related infections.

Esomeprazole 40 mg twice daily in triple therapy and the efficacy of Helicobacter pylori eradication related to CYP2C19 metabolism

AIM

To determine whether an increased dosage of esomeprazole 40 mg twice daily in triple therapy improved the Helicobacter pylori eradication rate for patients with different genotypes of S-mephenytoin 4'-hydroxylase (CYP2C19).

METHODS

Two hundred H. pylori-infected dyspeptic patients were randomized to receive clarithromycin 500 mg twice daily and amoxicillin 1 g twice daily plus either omeprazole 20 mg or esomeprazole 40 mg twice daily for 1 week. Six weeks later, the success of H. pylori eradication was defined. The genotyping of CYP2C19 in each patient was defined as homologous, heterologous extensive metabolizer or poor metabolizer.

RESULTS

The age, gender, drug compliance and proportion of CYP2C19 genotypes were similar between the two groups. The H. pylori eradication rates were also similar between the omeprazole group and the esomeprazole group (intention-to-treat analysis: 79% vs. 86%, P > 0.05; per-protocol analysis: 85% vs. 94%, P > 0.05). For patients classified as homologous extensive metabolizers, the per-protocol H. pylori eradication rate was significantly higher in the esomeprazole group than in the omeprazole group (93% vs. 76%, P < 0.05).

CONCLUSION

Esomeprazole 40 mg twice daily for triple therapy may improve the H. pylori eradication compared to omeprazole-based therapy, but only for homologous extensive metabolizers of CYP2C19.

The presence of immunoglobulins in the gastric juice of patients infected with Helicobacter pylori is related to a reduced secretion of acid

BACKGROUND

It has been reported that treatment with proton pump inhibitors (PPI) leads to partial elimination and suppression of Helicobacter pylori. In theory, since acid is known to denature immunoglobulins, this antibacterial activity of PPI may be due to a reduction in the acid output favouring humoral immunity.

MATERIALS AND METHODS

We analysed prospectively fasting gastric juice in 54 consecutive patients attending upper endoscopy for pH and levels of IgG, IgA and IgM. In addition, two antral and two corpus biopsies were obtained and histologically examined for the presence of H. pylori.

RESULTS

41/54 patients were infected with H. pylori. Immunoglobulines in the gastric juice of these patients were found in 25/41 (IgG), 27/41 (IgA), and 29/41 (IgM) patients. There was a highly significant difference in the gastric pH when H. pylori infected patients with measurable IgG, IgA, or IgM were compared with those in whom no immunoglobulines were found (median pH: 6 vs. 2 in each group; p <.001)

CONCLUSIONS

There is a close correlation between a high gastric pH and the presence of IgG, IgA, and IgM antibodies. Hence, it may be speculated that the efficacy of humoral immunity following H. pylori infection depends on a high pH such as resulting from PPI treatment.

Pantoprazole versus one-week Helicobacter pylori eradication therapy for the prevention of acute NSAID-related gastroduodenal damage in elderly subjects

AIM

To compare the efficacy of pantoprazole vs. a one-week Helicobacter pylori eradication therapy for the prevention of NSAID-related gastroduodenal damage.

METHODS

Patients over 60 years old with symptoms and/or a history of ulcer who needed NSAID treatment were evaluated by endoscopy. H. pylori positive subjects who had no severe gastroduodenal lesions were randomized to take, concomitantly with NSAID therapy, either: (i) pantoprazole 40 mg daily plus amoxycillin 1 g b.d. and clarithromycin 250 mg b.d. for 1 week (35 subjects, Group PAC) or (ii) pantoprazole 40 mg daily for 1 month (34 subjects, Group P). Endoscopy was repeated after 1 month.

RESULTS

A significantly higher incidence of severe gastroduodenal damage was found in Group PAC than in Group P (29% vs. 9%, P<0.05). The percentages of patients worsened, unchanged and improved after 1 month were, respectively: Group PAC: 46%, 46%, and 9% and Group P: 7%, 65%, and 29% (P<0.0008). The percentage of H. pylori-negative subjects was 89% in Group PAC and 52% in Group P (P=0.0009). The incidence of gastroduodenal damage was higher in Group PAC treatment failures than in cured patients (50% vs. 25.8%, P=ns).

CONCLUSION

One month of pantoprazole was more effective than a proton pump inhibitor-based triple therapy in the prevention of gastroduodenal damage in elderly H. pylori-positive NSAID users.

Conservation of the cag pathogenicity island of Helicobacter pylori: associations with vacuolating cytotoxin allele and IS605 diversity

BACKGROUND & AIMS

Specific regions of the cag pathogenicity island (PAI) believed to enhance the virulence of Helicobacter pylori, as well as vacuolating cytotoxin gene alleles and IS605 inserts, were investigated to define diversity within infecting strain populations from patients with peptic ulcer disease and from healthy individuals.

METHODS

The H. pylori studied comprised 67 isolates from 26 subjects and 14 reference strains. Specific polymerase chain reaction assays were used to test for cagA and picB in the cagI region, the virD4 homologue in the cagII region, IS605 in the genome and in the cag PAI, the "empty site" indicating absence of the cag PAI, and different vacA gene alleles.

RESULTS

Most (89%) subjects were infected by H. pylori with a contiguous cag PAI. No intermediate forms were found. IS605 was not detected within the cag PAI of any strain but was present elsewhere in the genomes of strains from 62% of subjects. Twenty individuals were infected with genotypically conserved populations of H. pylori. Six subjects had mixed infections, and in 3 of these cag(+)/cag(-) variants were present.

CONCLUSIONS

The cag PAI-positive H. pylori was a feature of most infected individuals, irrespective of severity of associated disease. Combined genotyping showed that 8 individuals (31%) had mixed infections, which suggests that strain population structure may be an additional contributing factor in disease development.