Adherence of Helicobacter pylori to HEp-2 cells.

The adherence of 25 strains of Helicobacter pylori was evaluated in HEp-2 cells. These bacterial isolates, obtained from Chilean patients with gastric disorders, were also tested for haemagglutination of human red blood cells. Adherence of HEp-2 cells was expressed as a common property of all strains, irrespective of whether the cultures were grown on semi-solid or in liquid media. Previous reports that haemagglutinating activity was present in cells grown only on semi-solid media were confirmed. Adherence to HEp-2 cells was suppressed when bacterial cells were pretreated with homologous or heterologous whole human serum, containing specific antibodies of H. pylori. Adherence remained unaltered when bacterial cells were similarly treated with normal serum lacking specific antibodies. These observations imply that adhesions are expressed in vivo and suggest that an adherence mechanism, not depending on the expression of specific haemagglutinin antigen, operates for H. pylori.

Helicobacter pylori infection in Chile.

This article summarizes studies designed to evaluate the role of Helicobacter pylori infection in Chile, described in 21 reports from nine centers in various Chilean regions published between 1985 and 1995. According to their data, H. pylori infection is quite frequent among patients with a variety of gastric conditions, including adults (43%-92%) and children (6%-100%). Levels of specific IgG antibodies to H. pylori are also elevated among patients with duodenal ulcers (100%) and gastritis (86%) as well as asymptomatic adults (75%). Combination therapy with three (but not two) drugs has been proved effective, with clinical improvement, ulcer cure, and H. pylori eradication occurring in well-controlled studies. Available evidence suggests that antibiotic resistance is not a major problem in treatment. The H. pylori reinfection rate is low (4.2% per year), suggesting that combination therapy with three drugs constitutes a cost-effective alternative for treating colonized symptomatic patients. Concurrent preliminary studies revealed that antibodies to VacA but not CagA proteins correlate with disease severity in Chilean patients. It can be concluded that local research assists local administrators of health resources to implement adequate policies to prevent, control, and treat H. pylori-related pathologies.

[Prospective study of erradication of Helicobacter pylori in patients with duodenal ulcer: analysis of antral and gastric body biopsies]. / Estudio prospectivo de erradicación de Helicobacter pylori en ulcerosos duodenales: análisis de biopsias de antro y cuerpo gástrico.

Omeprazole may not eradicate Helicobacter pylori from the stomach but rather displace it from the antrum to the stomach body. This fact could interfere with colonization studies in patients receiving the drug. The aim of this study was to assess the presence of Helicobacter pylori, defined as a positive urease test, culture or microscopical examination, in antral and gastric body biopsies in patients receiving treatment with omeprazole. Sixty four paired antral and gastric body biopsies obtained at the end of a 28 day course of omeprazole, 62 obtained four months later, 40 obtained eight months later and 23 obtained 12 months later were analyzed. There was a 92% concordance between antral and gastric body biopsies for the presence of Helicobacter pylori. However, nine of the samples obtained at 28 days (14%) were negative for H pylori in the antrum but positive in the gastric body. It is concluded that for early assessment of Helicobacter pylori eradication after omeprazole treatment, paired biopsies of antrum and gastric body are needed.

Low H. pylori reinfection rate after triple therapy in Chilean duodenal ulcer patients.

OBJECTIVES: We studied prospectively in a single-blind controlled manner the efficacy of 4-wk triple-antibiotic therapy, with amoxicillin (500 mg p.o., t.i.d.), metronidazole (250 mg p.o., t.i.d.), and bismuth subsalicylate tablets (524 mg p.o., q.i.d.), plus omeprazole (20 mg p.o., q.d.) and compared it with omeprazole (id) in the treatment of duodenal ulcer (DU) patients colonized with Helicobacter pylori. METHODS: One hundred DU patients were entered prospectively over a 12-month period. Fifty-seven of them received triple therapy plus omeprazole and 43 received omeprazole alone. Clinical, endoscopic, and bacteriological evaluations were performed on admission and at 28 days, 4, 8, and 12 months after treatment. RESULTS: After 4-wk treatment (day 28), the ulcer healing rate was high, but there was no significant difference between rates in the triple therapy and omeprazole groups (99% vs. 91%). In contrast, the long-term DU recurrence rate after 12-month follow-up was significantly lower (p > 0.01) for triple therapy (3/57, 5%), compared with omeprazole (34/43, 79%). The difference (higher relapse rate for omeprazole-treated patients) was significant (p < 0.001) by the second evaluation, 4 months after treatment. The eradication rate of H. pylori was also significantly higher among DU patients treated with triple therapy (p < 0.001) during all prospective evaluations, grand mean, 82% (range 82-87%), compared with the omeprazole-treated group, in which there were no cases in which H. pylori was eradicated. Follow-up revealed that 2/47 H. pylori-eradicated patients became reinfected after 1 yr, giving a reinfection rate of 4.2 patient/yr. CONCLUSIONS: Four-week triple-antibiotic therapy plus omeprazole constitutes an adequate alternative for treatment of Chilean DU patients.