Abstract

Background. Treatments for Helicobacter pylori ( H. pylori ) eradication include the use of antibiotics and a proton-pump inhibitor. Antibiotic resistance is a major concern for two drugs: levofloxacin and clarithromycin. The aim was to determine the prevalence of levofloxacin resistance (LevoR) and clarithromycin resistance (ClaR) in an urban population in Santiago, Chile. Methods. Gastric mucosa biopsies were obtained for DNA isolation from 143 H. pylori - positive individuals aged 18–80 years. Direct sequencing of the quinolone-resistance determining region (QRDR) of the gyrA gene was used to determine LevoR. ClaR was determined using restriction-fragment length polymorphism or 5’exonuclease assay. Results. The prevalences of LevoR and ClaR were 29 and 27%, respectively. LevoR was higher in women than in men (39 vs. 13%, p < 0.001), while no sex differ- ence was observed for ClaR ( p = 0.123). The prevalence of LevoR increased with age ( p -trend = 0.004) but not for ClaR ( p -trend = 0.054). In sex-stratified analyses, both LevoR and ClaR increased with age only among women. Older women ( > 50 years) had a higher probability to carry LevoR strains as compared to men. The prevalence of dual LevoR and ClaR was 12.6%. Conclusions. The prevalence of ClaR and LevoR is high in Santiago, according to Inter- national guidelines that recommend avoiding schemes with antibiotic resistance > 15%. Our findings provide evidence to re-evaluate current therapies and guide empirical firstand second-line eradication treatments in Chile. © 2021 Instituto Mexicano del Seguro