Use of the ''Polymerase Chain Reaction'' for the diagnosis of Helicobacter pylori infection.

PURPOSE: H. pylori infection can be diagnosed by means of non-invasive tests or invasive techniques using endoscopy. The choice of the test depends on available instruments, type of diseases, aim of diagnostic research (therapeutic or epidemiological) and test features. PCR is able to reveal pathogenic germs in biological material with very high sensitivity and specificity. In vitro DNA amplification method consists of hybriding denaturated DNA by means of two oligonucleotide primers that allow to copy DNA fragment. The aim of our study was to determine, using PER, H. pylori colonization in the gastric mucosa of 18 consecutive patients under-went gastroscopy. MATERIALS AND METHODS: Eighteen patients complaining of dyspeptic symptoms and referred to us for upper GI endoscopy participated in the study. The studied population comprised 9 males and 9 females with mean age of 55.4 yrs (range 26-73 years). All patients underwent gastroscopy during which 4 biopsies from the antrum and 4 from the corpus were obtained for Giemsa stain, PCR analysis and histologic examination. A pair of synthetic oligonucleotides for H. pylori urease A gene, designated as HPU1 and HPU2, were used. Urease A gene fragment amplified by PCR was analyzed by 1.5 agarose gel electrophoresis. Positivity for H. pylory corresponded to PCR DNA products migrating at 411 bp after staining with ethidium bromide. RESULTS: The patients were divided into two groups, according to H. pylori infection, determined by means of Giemsa stain: group A, comprising 11 H. pylori-positive patients; and group B, with 7 H. pylori-negative patients. Our PCR assay of gastric mucosa samples proved positive in 7 cases of group A (63.6%), whereas it always proved negative among group B subjects (100%). CONCLUSIONS: Our findings, apparently in contrast with the high sensitivity of PCR, may be attributed to the lower specificity of histology or, alternatively, the absence of H. pylori in the samples tested by PCR due to the patchy distribution of H. pylori colonization in the gastric mucosa. These observations are in agreement with those from other investigations.

Low-dose omeprazole plus clarithromycin and either tinidazole or amoxycillin for Helicobacter pylori infection.

BACKGROUND: The aim of our study was to compare two 1-week, low-dose triple therapies for Helicobacter pylori eradication. METHODS: One hundred consecutive patients, suffering from dyspeptic symptoms with H. pylori infection, were randomly allocated to 7 days of treatment with omeprazole 20 mg o.m. plus clarithromycin 250 mg b.d. and either tinidazole 500 mg b.d. (group A: n = 50, 19 with peptic ulcer) or amoxycillin 1000 mg b.d. (group B: n = 50, 20 with peptic ulcer). H. pylori-status was evaluated by means of histology, culture and urease test, at entry and 8 weeks after treatment. RESULTS: Three patients did not complete the treatment. H. pylori eradication was obtained in 35 patients from group A (73%) (95% CI, 55-82%) and in 40 patients from group B (82%) (95% CI, 66-90%). On intention-to-treat analysis, the rates of eradication were similar. Side-effects occurred in seven patients from group A (14.58%) and in four patients from group B (8.33%), but none discontinued therapy because of side-effects. CONCLUSION: Both triple 1-week, low-dose omeprazole therapies gave good eradication rates with infrequent side-effects.

Clinical assessment of the relationship of Helicobacter pylori to gastroduodenal pathologies. A prospective analysis of 253 consecutive patients.

The aim of our study was to evaluate the relationship between Helicobacter pylori infection and various gastroduodenal diseases. We also took into consideration alcohol intake and smoking. Two-hundred and fifty-three consecutive patients with ulcer-like symptoms underwent gastroscopic and histological examinations. H. pylori status was evaluated by means of culture, Giemsa stain and CP-test, upon obtaining bioptic samples of gastric mucosa. Two hundred eighteen patients were affected by gastritis, 171 of which were H. pylori positive (78.4%); of 164 patients with active gastritis, 158 were H. pylori positive (96.3%). In 63 patients with duodenal ulcer, H. pylori was present in 58 cases (92.1%). Of 14 patients with gastric ulcer, 11 were H. pylori positive (78.6%). Out of 133 patients with duodenitis associated with active ulcer or a history of previous ulcer, H. pylori was found in 112 patients (84.2%). Among the 27 patients with "autonomous" duodenitis, 18 were H. pylori positive (66.6%); the comparison between the two groups of patients with duodenitis concerning H. pylori infection was statistically significant (p = 0.033). Of the 119 patients tested for acquired MALT, 39 were found positive (32.7%); among these 34 patients were H. pylori positive (87.1%) and only 5 patients were H. pylori negative (12.9%). Thus our study confirms the importance of H. pylori in gastroduodenal pathology underlining its role in the development of acquired MALT (mucosa associated lymphoid tissue) for its possible evolution in low grade B cell primary gastric lymphoma. Alcohol intake and smoking do not appear to play a role in H. pylori infection.