H pylori eradication failure with recommended triple therapy is mainly related to antibiotic resistance. However,IN VITRO culture of H pylori is uneasy and is not performed in routine practice. A molecular test of antibiotic resistance easy to perform is now available. The aim of the study was to compare eradication rates obtained with the standard treatment and with a treatment guided by the results of the molecular detection of antibiotic resistance.

At the present time, H pylori infection is treated with a standard triple therapy. Treatment of naïve patients with triple therapy ( PPI+amoxicillin+clarithromycin for 7 days) markedly decreased last years to reach 70% due to a clarithromycin resistance rate about 20% in France. In case of failure, the recommended second line treatment (PPI+amoxicillin+metronidazole for 14 days) gives a success rate of 60%. However, as culture is uneasy and is only possible in specialised labs sensitivity to antibiotics is not currently studied before treatment.

The aim of the study was to evaluate clinical and medico-economic benefit of the molecular detection of antibiotic resistance in order to guide the treatment.

The test is performed after DNA extraction from biopsy specimens taken at gastroscopy allowing rapid detection of H pylori and clarithromycin or quinolone resistance.

Patients with bacteriologically proven H pylori infection will be randomly allocated to either empirical usual treatment with PPI , amoxicillin 1g, clarithromycin 500 mg X 2 /day for 7 days in naïve patients and PPI, amoxicillin 1g,metronidazole 500 mg X 2 /day for 14 days in patients who failed a first line treatment , or to treatment guided by the molecular test: PPI , amoxicillin 1g, clarithromycin 500 mg X 2 /day for 7 days in case of sensitivity to clarithromycin.In case of resistance to clarithromycin, quinolone should be given and in case of resistance to quinolone clarithromycin should be given. In case of resistance to both antibiotics metronidazole should be given.

Eradication will be assessed by performing 4 weeks after the completion of treatment with Urea Breath Test.

Inclusion Criteria:

• H pylori infection bacteriologically confirmed
• Age > 18 years
• Naïve patient or one failure of the first line recommended treatment
• Patient referred to one out of the centres participating in the study

Exclusion Criteria:

• H pylori positive patient with at least failure of two lies of treatment
• patients with previous adverse event with PPI, amoxicillin, clarithromycin, levofloxacin or metronidazole
• PPI or antibiotic treatment in progressor stopped for less than 4 weeks
• patient with other severe sickness