Failure of first line eradication treatment significantly increases prevalence of anti-microbial resistant helicobacter pylori clinical isolates

Abstract

Objectives: H. pylori infection is a major health problem world wide and effective eradication of the infection is mandatory. The efficacy of recommended eradication regimens is approximately 70%. In order to avoid treatment failure and the consequent development of secondary resistance(s) it is important to choose the most appropriate first line treatment regimen. This choice should also be made based on the knowledge of the antimicrobial resistance peculiar to a given geographical area. We evaluated the prevalence of antimicrobial resistant H. pylori strains isolated from naive patients and from patients with previous unsuccessful treatments.

Methods: We studied 109 H. pylori-infected subjects (Group 1) who had never received an eradication treatment and 104 H. pylori-infected subjects (Group 2) who had failed one or more eradication treatments. Resistance to amoxicillin (AMO) , tetracycline (TET) , clarithromycin (CLA), metronidazole (MET) and levofloxacin (LEV) was determined by epsilometer test. Significance of differences was evaluated by χ² test.

Results: 1) The prevalence of antimicrobial resistance was 0% vs 3.1% to AMO, 0% vs 2% to TET, 27% vs 41.3% to MET (p<0.05), 18% vs 45.8% to CLA (p<0.05), 3% vs 14.6% to LEV (p<0.05) in Group 1 vs Group 2, respectively; 2) In Group 2 , there was an increased prevalence of H. pylori strains resistant to multiple antimicrobials.

Conclusions: This study confirms the high prevalence of H. pylori strains resistant to CLA and MET and indicates that unsuccessful treatments significantly increase resistance. Choosing eradication regimens other than standard triple therapy as first line therapy should be advisable in areas with high primary antimicrobial resistance prevalence.