***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: ABSTRACT Culture and susceptibility testing of Helicobacter pylori strains was performed in a large multinational , multicenter r and omized clinical trial . Culture was carried out on gastric biopsy sample s obtained from 516 patients at entry and had a sensitivity of 99 % when the [13C]urea breath test was used as a reference . Susceptibility testing was performed for clarithromycin and metronidazole on 485 strains by an agar dilution method and the epsilometer test ( Etest ) and for amoxicillin by an agar dilution method only . Resistance to clarithromycin  ( > 1 μg/ml ) was found in 3 % of the H. pylori strains , with a perfect correlation between Etest and agar dilution methods . Resistance to metronidazole  ( > 8 μl/ml ) was found in 27 % of the strains by agar dilution , but there were important discrepancies between it and the Etest method . No resistance to amoxicillin was found . The logarithms of the MICs of the three antibiotics against susceptible strains had a distribution close to normal . The impact of resistance was tested in the four arms of the trial . There were not enough clarithromycin-resistant strains to evaluate the impact of resistance on the cure rate of clarithromycin-based regimens . For metronidazole-resistant strains , the impact noted in the clarithromycin-metronidazole arm was partially overcome when omeprazole was added ( 76 % eradication for resistant strains versus 95 % for susceptible strains ) . Secondary resistance to clarithromycin occurred in strains from 12 of 105 patients ( 11.4 % ) after the failure of a clarithromycin-based regimen to effect eradication . The detection of point mutations in clarithromycin-resistant strains was performed by a combination of PCR and restriction fragment length polymorphism . Mutations ( A2142 G and 2143 G ) were found in all strains tested except one . This study stresses the importance of performing susceptibility tests in clinical trials in order to explain the results of different treatments BACKGROUND Helicobacter pylori eradication with omeprazole , amoxycillin , and metronidazole is both effective and inexpensive . However , eradication rates with different dosages and dosing vary , and data on the impact of resistance are sparse . In this study , three different dosages of omeprazole , amoxycillin , and metronidazole were compared , and the influence of metronidazole resistance on eradication was assessed . METHODS Patients ( n = 394 ) with a positive H. pylori screening test result and endoscopy-proven duodenal ulcer in the past were enrolled into a multicenter study performed in four European countries and Canada . After baseline endoscopy , patients were r and omly assigned to treatment for 1 week with either omeprazole , 20 mg twice daily , plus amoxycillin , 1,000 mg twice daily , plus metronidazole , 400 mg twice daily ( low M ) ; or omeprazole , 40 mg once daily , plus amoxycillin , 500 mg three times daily , plus metronidazole , 400 mg three times daily ( medium M ) ; or omeprazole , 20 mg twice daily , plus amoxycillin , 1,000 mg twice daily , plus metronidazole , 800 mg twice daily ( high M ) . H. pylori status at entry was assessed by a 13C urea breath test and a culture . Eradication was defined as two negative 13C-urea breath test results 4 and 8 weeks after therapy . Susceptibility testing using the agar dilution method was performed at entry and in patients with persistent infection after therapy . RESULTS The eradication rates , in terms of intention to treat ( ITT ) ( population n = 379 ) ( and 95 % confidence interval [ CI ] ) were as follows : low M 76 % ( 68 % , 84 % ) , medium M 76 % ( 68 % , 84 % ) , and high M 83 % ( 75 % , 89 % ) . By per- protocol analysis ( population n = 348 ) , the corresponding eradication rates were : low M 81 % , medium M 80 % , and high M 85 % . No H. pylori strains were found to be resistant to amoxycillin . Pre study resistance of H. pylori strains to metronidazole was found in 72 of 348 ( 21 % ) of the cultures at entry ( range , 10%-39 % in the five countries ) . The overall eradication rate in pre study metronidazole-susceptible strains was 232 of 266 ( 87 % ) and , for resistant strains , it was 41 of 70 ( 57 % ; p < .001 ) . Within each group , the results were as follows ( susceptible/resistant ) : low M , 85%/54 % ; medium M , 86%/50 % ; and high M , 90%/75 % . There were no statistically significant differences among the treatment groups . 23 strains susceptible to metronidazole before treatment were recultured after therapy failed ; 20 of these had now developed resistance . CONCLUSIONS H. pylori eradication rates were similar ( approximately 80 % ) with all three regimens . Metronidazole resistance reduced efficacy ; increasing the dose of metronidazole appeared not to overcome the problem or significantly improve the outcome . Treatment failure was generally associated with either pre study or acquired metronidazole resistance . These findings are of importance when attempting H. pylori eradication in communities with high levels of metronidazole resistance Objectives : Rabeprazole is a new fast acting proton pump inhibitor that has recently been proven to be effective in the treatment of peptic ulceration and reflux esophagitis . The aim of this study was to evaluate rabeprazole in combination with antibiotics for the eradication of Helicobacter pylori ( H. pylori ) in patients with chronic active gastritis with or without peptic ulcer disease . Methods : Seventy-five H. pylori-infected patients were r and omized in a double-blind fashion to receive a 7-day treatment regimen consisting of : RAC , RAM , RCM , or RC ( R = rabeprazole 20 mg b.d . , A = amoxycillin 1 g b.d . , C = clarithromycin 500 mg b.d . , M = metronidazole 400 mg b.d . ) . R and omized patients were H. pylori-positive by gastric biopsy urease test , histology and 13C urea breath test ( 13C-UBT ) . H. pylori eradication was assessed by 13C-UBT , 4 and 8 wk after finishing treatment . Endoscopy with histology and culture for antibiotic sensitivity testing was performed pretreatment and if treatment failed . Results : On an intention-to-treat analysis , treatment success was : RCM 100 % , RAC 95 % , RAM 90 % , and RC 63 % . The most common side effects were loose stools , headache , and taste disturbance , but there were no serious adverse events related to the study medication . The two patients failing RAM treatment had metronidazole-resistant strains before and after treatment . None of the pretreatment H. pylori isolates from six patients failing RC were clarithromycin resistant , but three of five successfully cultured posttreatment had developed clarithromycin resistance . Conclusion : Rabeprazole-based triple therapy with two antibiotics for 1 wk is safe and effective in eradicating H. pylori . Dual therapy with clarithromycin is less successful , and the majority of treatment failures develop clarithromycin resistance OBJECTIVES To treat previously untreated adult patients infected with Helicobacter pylori with one of two regimens in an ambulatory community setting to assess the efficacy and safety of these regimens . METHODS Sixty five adult patients with histologically confirmed H. pylori infection were r and omly assigned in this open cohort study to 2 wk , low dose , twice daily treatment with omeprazole 20 mg and clarithromycin 250 mg ( OC ) ( n = 31 ) or OC plus metronidazole 500 mg ( OCM ) ( n = 34 ) . At least 4 wk after treatment , H. pylori status was assessed by histology ( four gastric biopsies , two each from antrum and body ) . RESULTS Triple therapy with OCM was significantly better than dual therapy with OC in intent-to-treat ( 82.4 vs 58.1 % , p = 0.03 ) and per protocol analysis ( 93.3 vs 62.1 % , p = 0.004 ) . Although there were frequent side effects  ( OC 19/31 61.3 % ; OCM 22/34 64.7 % with at least one side effect ) , these were generally mild , and patients were able to complete nearly all of their medications  ( OC 97.2 % , OCM 96.7 % of pills taken ) . The only patient withdrawn due to medication side effects was in the OC arm . CONCLUSIONS Triple therapy with OCM in a community setting eradicates H. pylori more effectively than dual therapy with OC . OCM is tolerated with high compliance despite frequent minor side effects and appears safe without the development of serious adverse events OBJECTIVES Triple therapy and amoxycillin plus omeprazole are the two most widely recommended regimens for the eradication of Helicobacter pylori . However , no controlled studies with a large number of cases are available for the reliable comparison of these two regimens . The aim of this controlled , r and omized , prospect i ve study was to compare the effect of these two regimens and a further regimen for metronidazole-resistant patients on duodenal ulcer healing , H. pylori eradication , and prevention of ulcer relapse . METHODS Patients ( n = 144 ) with proven duodenal ulcer ( DU ) were r and omized to one of the three following regimens : group A , omeprazole ( 2 x 40 mg ) plus amoxycillin ( 4 x 500 mg ) for 2 wk ; group B , triple therapy : bismuth nitrate ( 4 x 375 mg ) plus metronidazole ( 4 x 250 mg ) and tetracycline ( 4 x 500 mg ) daily for 2 wk and ranitidine ( 150 mg ) for the first week and bismuth nitrate ( 4 x 375 mg ) alone for a further 2 wk ; group C , omeprazole ( 20 mg ) plus amoxycillin ( 4 x 500 mg ) and tinidazole ( 2 x 500 mg ) for 2 wk . RESULTS A total of 46 patients in group A , 39 in group B , and 43 in group C completed the study . One patient in group A and three in group B did not tolerate the regimens and dropped out of the study . Control endoscopy was performed 8 wk after the start of treatment and when symptoms appeared ( up to 1 yr after the start of treatment ) . In subjects who completed the study , both the healing rate of DU in group B ( 97 % compared with 74 and 73 % in A and C , respectively , p < 0.02 ) and the H. pylori eradication rate in group B ( 85 compared with 35 % , p < 0.0001 in A and 58 % , p < 0.02 , in C ) were significantly higher than in groups A and C. The symptomatic ulcer relapse during the 1-yr follow-up in patients with initially healed ulcers was similar in all groups ( 18 , 16 , and 19 % in A , B , and C , respectively ) . The predictor of healing using logistic regression analysis was night pain ( p < 0.05 ) . The predictor of H. pylori eradication was sex ( p < 0.05 ) . CONCLUSION The 2-wk triple therapy plus an additional 2-wk treatment with the bismuth derivative ( without a prolonged administration of acid suppressing drugs ) seems to be an effective and economic treatment not only for the eradication of H. pylori but also for the healing of acute DU . The higher incidence of side effects found after triple therapy compared with the other two regimens was tolerated by the patients : In Asian countries with limited re sources , clarithromycin‐based triple therapy may not be readily available . There are also few direct comparisons of different regimens in Asia OBJECTIVES Our objectives were to determine the effect of dual therapy with omeprazole and amoxicillin and of triple therapy with omeprazole , amoxicillin , and metronidazole in the eradication of  Helicobacter pylori ( HP ) and to study the long-term results of eradication in these patients . METHODS A prospect i ve , r and omized , controlled trial was performed . Patients who were recruited had unequivocal evidence of HP infection based on culture , histology , rapid urease test , and Gram 's stain of a tissue smear . Eradication was defined as the absence of bacteria in all tests performed on both corpus and antral biopsies . RESULTS The infection was eradicated in 15 of 19 ( 78.9 % ) patients r and omized to receive dual therapy and in 
    Output:
    
RESULTS The data supported the current worldwide recommendation to use proton pump inhibitor (PPI)-based triple therapy with clarithromycin and either metronidazole or amoxycillin .
There are , however , regional differences in success rates that are not completely explained by resistance to either metronidazole or amoxycillin .
For second-line therapy , quadruple therapy using a PPI with bismuth , metronidazole and tetracycline ( PPI-BMT ) is superior to an alternative PPI-based triple therapy .