Diagnosis and treatment of resistant H. pylori infection
Abstract number: s28
The management of H. pylori infection has been well established during the last 10 years. Recommendations were made in the Maastricht Conference in 1996, and were updated in 2000. Most of them have been used in other consensus conferences worldwide. Nevertheless, some points have emerged these past 4 years, which led to questions and discussions at the Maastricht-3 Conference.
Diagnosis pre treatment:
With regard to diagnostic tests, the discussion focused on the value of non-invasive tests other than the urea breath test (UBT). A first statement concluded that serology could be considered as a diagnostic test in some situations, e.g. bleeding ulcers, gastric atrophy, MALT lymphoma and current use of PPI or antibiotics. Indeed, PPI are a source of false negative results for all diagnostic tests except serology, and should be stopped at least 2 weeks before performing the test. In contrast, it was stated that neither the doctor tests (near-patient tests) nor the detection of H. pylori antibodies in urine and saliva, had any current role in the management of H. pylori infection. The situation is different for the stool test, which was considered acceptable, on the same grounds as UBT for H. pylori diagnosis, especially in the case of implementation of the test and treat strategy. The importance of performing culture for clarithromycin susceptibility testing, before using clarithromycin-based treatment as a first line treatment, was hardly debated. Culture was recommended if primary resistance to this antibiotic was higher than 1520% in the respective geographical area or population, as well as after 2 treatment failures. The importance of monitoring the primary antibiotic resistance in reference laboratories in different areas was also stressed. In the event that clarithromycin susceptibility testing under such circumstances is impossible, this antibiotic should not be used. In contrast, it was agreed that testing metronidazole susceptibility is not routinely necessary in the management of H. pylori infection. Metronidazole susceptibility testing needs further standardization before being recommended as a first line treatment.
How to treat?
The recommended first line therapy therefore remains PPI-clarithromycin-amoxicillin or metronidazole if the primary resistance to clarithromycin in the area is lower than 1520%. There is a small advantage to using metronidazole instead of amoxicillin and therefore, this combination was found to be preferable in areas where the prevalence of metronidazole resistance is lower that 40%. The consensus was also that a 14-day rather than 7-day treatment duration had a slight advantage in terms of treatment success. However, a 14-day treatment is not cost effective in most countries. Another addition to the Maastricht-2 Consensus is that bismuth-based quadruple therapies, when available, are acceptable as alternative first line therapies. With regard to second line therapies, bismuth-based quadruple therapies remain the best option. If unavailable, PPI-amoxicillin or tetracycline and metronidazole are recommended. As previously proposed, the rescue therapy after failure of 2 courses of different therapies should be based on antimicrobial susceptibility testing. For follow-up after H. pylori eradication, UBT remains the preferred test. If unavailable, a laboratory-based stool test preferably using monoclonal antibodies, could be used. The timing of this follow-up should be at least 4 weeks after the end of eradication treatment.
|Session name:||XXIst ISTH Congress|
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