Antimicrobial Resistance Patterns and Predictors in Helicobacter pylori Infection: A Real-World Cohort Study

Rising antimicrobial resistance has reduced the effectiveness of empirical eradication regimens for Helicobacter pylori (H. pylori) infection, particularly those containing clarithromycin. Local resistance surveillance and identification of clinical predictors of resistance are essential to guide treatment strategies. This study evaluated antimicrobial resistance patterns and clinical determinants of resistance in a real-world tertiary-care cohort. A retrospective observational study was performed, which included 352 adult patients with confirmed H. pylori infection managed between November 2022 and November 2025. Of these, 168 patients underwent culture and antibiotic susceptibility testing, while 184 received empirical therapy. Resistance rates were calculated according to the number of isolates tested for each antimicrobial agent (available-case analysis). Multivariable logistic regression analysis was used to identify independent predictors of resistance. Among susceptibility-tested patients, resistance to at least one antimicrobial agent was detected in 44.6%. Clarithromycin resistance was most frequent (42.5%), followed by metronidazole (36.4%) and levofloxacin (14.0%), whereas amoxicillin resistance remained low (2.4%). Multidrug resistance (MDR) based on available susceptibility data was observed in 12.5% of cases, most commonly involving dual clarithromycin-metronidazole resistance. Prior eradication therapy was independently associated with resistance (adjusted Odds Ratio aOR 2.41; 95% Confidence Interval CI 1.29-4.51; p = 0.006), while demographic factors were not. Clarithromycin resistance substantially exceeds recommended thresholds for empirical triple therapy in this setting. Prior eradication therapy is the principal predictor of resistance, supporting resistance-informed and stewardship-oriented management strategies.