High prevalence and risk factors of multiple antibiotic resistance in patients who fail first-line Helicobacter pylori therapy in southern China: a municipality-wide, multicentre, prospective cohort study.

Background: We aimed to study the prevalence of secondary antibiotic resistance of Helicobacter pylori in southern China and its risk factors, particularly geographical and socio-economic factors.

Methods: This was a municipality-wide, multicentre, prospective cohort study involving five major hospitals. Patients aged ≥18 years who failed first-line bismuth-based quadruple anti-H. pylori therapy between September 2016 and February 2018 were recruited. Participants underwent upper gastrointestinal endoscopy with biopsy from the antrum and body for H. pylori culture and antimicrobial susceptibility testing for six antibiotics (clarithromycin, levofloxacin, metronidazole, amoxicillin, tetracycline and furazolidone). Patients with failure of H. pylori culture were excluded. Participants completed a questionnaire profiling 22 potential risk factors of H. pylori infection and antibiotic resistance, including medical, social, household and birthplace factors.

Results: A total of 1113 patients failed first-line therapy, with successful H. pylori culture in 791 (71.1%) [male = 433 (54.7%); median age = 43 years]. Secondary resistance rates of dual antibiotics (clarithromycin + metronidazole and levofloxacin + metronidazole) and triple antibiotics (clarithromycin + levofloxacin + metronidazole) were 34.0%, 38.7% and 17.8%, respectively. Risk factors for clarithromycin + metronidazole resistance were history of ≥2 courses of H. pylori therapies [adjusted OR (aOR) = 1.71; 95% CI = 1.17-2.54], ≥3 household members (aOR = 2.00; 95% CI = 1.07-3.90) and family history of gastric cancer (aOR = 1.85; 95% CI = 1.18-2.85). Risk factors for levofloxacin + metronidazole resistance were age ≥40 years (aOR = 1.94; 95% CI = 1.37-2.75), lower gross domestic product per capita (aOR = 0.29; 95% CI = 0.10-0.80) and higher number of doctors/10 000 population (aOR = 1.59; 95% CI = 1.07-2.39). A higher human development index was of borderline significance (aOR = 2.79; 95% CI = 0.97-8.70).

Conclusions: The rates of secondary resistance of H. pylori to multiple antibiotics were high in southern China. Certain population-level risk factors were associated with levofloxacin + metronidazole resistance.