# Helicobacter pylori Infection and Antimicrobial Resistance Surveillance over 25 Years in Children in Gipuzkoa, Northern Spain

## TL;DR

This study analyzed Helicobacter pylori infections and antibiotic resistance in children in Gipuzkoa, Spain, over 25 years, finding high resistance to some key antibiotics.

## Contribution

The study provides a long-term surveillance of H. pylori infection and resistance patterns in children in a specific region.

## Key findings

- H. pylori infection prevalence in children was 26.9% over 25 years.
- High resistance to clarithromycin (28.9%) and metronidazole (19.4%) was observed.
- All isolates remained sensitive to amoxicillin and tetracyclines.

## Abstract

The diagnosis and treatment of Helicobacter pylori infection in children represent a major public health problem worldwide, and although prevalence in developed countries has declined, concern about antibiotic resistance continues to grow. This retrospective study aimed to analyze H. pylori infections in children under 15 years of age in Gipuzkoa (Basque Country, Spain) over a 25-year period and to describe patterns of primary and secondary antimicrobial resistance. All diagnostic tests received at a tertiary referral hospital between 2000 and 2024 were reviewed: urea breath test, gastric biopsy culture, string test, and stool antigen detection. Antimicrobial susceptibility testing was performed using the E-test gradient diffusion method. Out of 2855 children investigated, 26.9 were infected with H. pylori. Eradication control was performed in 62.5% (n = 480) of cases. Antimicrobial susceptibility testing was achieved in 96.5% out of the 400 isolates studied. All isolates were sensitive to amoxicillin and tetracyclines. Primary resistance to clarithromycin, metronidazole, and levofloxacin was 28.9%, 19.4%, and 8.9%, respectively, and secondary resistance was 38.7%, 29.7%, and 5.9%, respectively. H.pylori infection remains a challenge in pediatric patients, and the high resistance observed to clarithromycin and metronidazole makes it necessary to monitor the susceptibility of H.pylori and confirms the need for targeted treatment.