Helicobacter pylori has an important role in the etiology of gastric diseases being the agent of chronic gastritis, peptic and duodenal ulcers and is associated to the increment of gastric cancer and lymphoma. The most used H. pylori therapeutic option consists of a double or triple antibiotic regimen (clarithromycin, tetracycline, metronidazole and amoxicillin) associated to a pump proton inhibitor. Still, there is not a standard regimen to treat H. pylori, being frequent the occurrence of individuals that do not respond to the medication, maintaining the infection. Among the factors involved in the lack of H. pylori infection treatment, emergency of bacterium strains resistant to antibiotics, is considered the most important. H. pylori is a slow growing microaerophilic organism, difficult to be cultivated and to which there is not a standardized antibiotic susceptibility test. Thus, molecular tests consisting of direct detection of genes mutations that confer to H. pylori resistance to antibiotics will be of a great utility. Therefore, considering the importance of this bacterium in the etiology of gastric diseases and the crescent development of clarithromycin and tetracycline resistance by H. pylori, this project aim to investigate the primary resistance of H. pylori to clarithomycin from 1200 clinical samples obtained from individuals of Marilia, SP, submitted to upper digestive endoscopy, since February 2004. It will be employed PCR as a diagnostic method for H. pylori and the identification of mutations in the 23S rRNA gene, by analysis of restriction fragments, involved in clarithromycin resistance.
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