Antimicrobial resistance patterns, molecular resistance prediction, and treatment outcomes in pediatric Helicobacter pylori infection.

Abstract

Antimicrobial resistance increasingly complicates empirical treatment of pediatric Helicobacter pylori (H. pylori) infection. We examined resistance patterns and the relationship of molecular and culture-based results to treatment and eradication outcomes. We retrospectively studied children who underwent clinically indicated endoscopy with paired polymerase chain reaction (PCR) and culture testing between October 2022 and October 2024. Resistance-associated variants were identified by PCR and Sanger sequencing. Culture-positive isolates underwent antimicrobial susceptibility testing, which informed treatment selection. Eradication was assessed by carbon-13 urea breath testing. Of 145 children, 128 (88.3%) were PCR positive and 92 were culture positive. Phenotypic resistance to clarithromycin (CLA), metronidazole (MTZ), and levofloxacin (LVX) was 82.6%, 81.5%, and 29.3%, respectively; 72.8% of isolates were resistant to at least two antibiotics. Molecular prediction of CLA nonsusceptibility had 98.8% sensitivity, 90.9% specificity, and 97.8% accuracy; corresponding values for LVX were 90.9%, 97.7%, and 95.5%. Eradication was achieved in 86 of 97 treated children (88.7%), and 80 of 84 treated culture-positive children received phenotypically concordant regimens. CLA and MTZ resistance and multidrug resistance were frequent. Molecular analysis of 23S rRNA and gyrA complemented culture-based susceptibility testing in treatment selection. Clarithromycin and metronidazole resistance exceeded 80%, and nearly three quarters of the pediatric H. pylori isolates were resistant to at least two antibiotics, substantially limiting empirical treatment options. Molecular analysis of 23S rRNA and gyrA closely reflected phenotypic clarithromycin and levofloxacin nonsusceptibility, whereas molecular findings for other antibiotics were less readily interpretable. By linking molecular and culture-based resistance results with the regimens prescribed and subsequent eradication outcomes, this study shows how the two approaches can complement each other in routine pediatric care.