Primary antibiotic resistance and effectiveness of helicobacter pylori triple therapy in ulcero-inflammatory pathologies of the upper digestive tract

Objectives : To determine firstly, the rates of primary antimi- crobial resistance for Helicobacter pylori - associated upper - diges- tive lesions in relation to the success rate of triple therapy ; and secondly, the performance of HpSA stool antigen detection test for control of eradication after treatment. Methods : Prospective open study of 436 patients who under- went upper - digestive tract endoscopy with biopsies for histologi- cal examination and culture between January 1 and July 31, 2002 at a University hospital in Brussels, Belgium. The primary resis- tance to antibiotics of H. pylori isolates was determined by disc diffusion method. Seventy of 164 infected patients agreed to be included in the treatment study with standard triple therapy with amoxicillin + clarithromycin + omeprazole adjusted on the basis of antibiogram results. Control of eradication was tested by 14C-Urea breath test and H. pylori Stool Antigen test (HpSA test). Results : Primary resistance to clarithromycin and metronida- zole was observed in 3% and 31% of the isolates, respectively. No primary resistance to amoxicillin and tetracycline was observed. By intention to treat analysis, H. pylori was eradicated in 56 (80%) patients included in the therapeutic study. Three (4%) patients were lost to follow-up. The rate of eradication failure was 20% (14/70), included 11 cases documented by a positive control test (14C-Urea breath test). In comparison with 14C-Urea breath test, the H. pylori Stool Antigen test showed a sensitivity of 100%, a specificity of 91%, PPV of 69%, and NPV of 100%. Conclusion : Standard triple therapy achieved 80% bacterial eradication in this patient population with a low prevalence of H. pylori primary antibiotic resistance. Our data confirm that the H. pylori Stool Antigen test displays a diagnostic performance similar to the breath test for control of eradication. (Acta gastro- enterol. belg., 2005, 68, 287-293).