Resumen

HERNANDEZ-CHAVARRIA, Francisco  y  RIVERA, Patricia. Historia natural de la infección por helicobacter pylori, su tratamiento antimicrobiano y el empleo de plantas medicinales. Rev. costarric. cienc. méd [online]. 2003, vol.24, n.3-4, pp.149-165. ISSN 0253-2948.

The members of the genus Helicobacter, described in 1989, colonize the stomachs and intestines of humans and several animal species. The number of species in this genus has expanded since 1983, when was described H. pylori, the type species, actually the genus includes more than 20 species. In humans H. pylori is recognized as the primary cause of chronic gastritis, gastric and duodenal ulcers, and some types of gastric cancer. Also, some species or Helicobacter-like organisms are occasional causes of septicemia in AIDS patients. Helicobacter spp. are Gram negative, catalasa, oxidase and urease positive, is 2,5 to 3,5 mm long and 0,5 to 1 mm diameter, microaerophilic, spiral to curved rods with one to several polar sheathed flagella localized at one end of the rod; at least three species showed periplasmic fibers. Epidemiological studies reveled that the prevalence of H. pylori infection is more common in developing than developed countries due to many factors associated with the environment, such as residential crowding, economical background, fecal contamination, availability of potable water, and other factors of the host and the agent, for example, the age of the patients and the H. pylori strain type, respectively. Although this agent is sensitive to many antimicrobial drugs in vitro, it is difficult to eradicate from the stomach, due to its acid niche; its extracellular localization because resides in the mucous layer over the gastric epithelium, and it develop resistance to the more common antibiotics used for its treatment, specially metronidazole. Single or dual therapies have unacceptably low cure rates; for that reason, there are proposed some triple of quadruple therapies, the formers include one or two antibiotics (metromidazole, amoxicillin, claritromycin, tetracycline), acid secretingsuppressor drugs, and bismuth compounds (Pepto Bismol or bismuth citrate). The quadruple therapies additionally incorporate a proton pump inhibitor. Commonly, the eradication rate of the different treatment protocols oscillate from 70 to 90%. The high cost of the treatment, specially the quadruple therapy, with poor tolerability and reducedcompliance in some patients, and the emergence of H. pylori strains resistance to antibiotics, are responsible of the low rate of cure reported, that failure in 10 to 30% of the cases. These facts induce to look for novel therapies, and the ethnomedicine has a millenary vast field of knowledge, and search for antibacterials plants extracts has gained renewed impetus.

Palabras clave : Helicobacter pylori; gastritis; peptic ulcers; therapy; medicinal plants.