High prevalence rate of Helicobacter pylori resistance to clarithromycin during long-term multiple antibiotic therapy for chronic respiratory disease caused by non-tuberculous mycobacteria

Background: Helicobacter pylori resistance to clarithromycin, probably due to the frequent use of this antibiotic for the treatment of other diseases, is the greatest obstacle against its eradication. Aim: To clarify the prevalence of clarithromycin-resistant H. pylori in patients with non-tuberculous mycobacterial lung disease receiving multiple antibiotic treatment, including clarithromycin. Methods: We enrolled 88 patients with non-tuberculous mycobacterial lung disease; 29 underwent upper gastrointestinal endoscopy for the diagnosis of H. pylori infection prior to treatment, and 60 underwent it during treatment. The diagnosis of H. pylori infection was confirmed by histological examination, urease test and microaerobic bacterial culture. The minimum inhibitory concentration of clarithromycin was determined and the DNA was analysed for each of the isolated H. pylori strains. Results: Patients during the treatment had a high prevalence rate of clarithromycin-resistant H. pylori (100%). Analysis of DNA of the clarithromycin-resistant H. pylori isolates revealed point mutations at A2142G or A2143G. Moreover, a linear correlation was found between the total cumulative dose of clarithromycin and the minimum inhibitory concentration. Conclusion: All patients with non-tuberculous mycobacterial lung disease being treated long-term with multiple antibiotics, including clarithromycin, harboured clarithromycin-resistant H. pylori in the stomach. Therefore, eradication of H. pylori before commencement of long-term therapy including clarithromycin should be recommended.