Antibiotic resistance of Helicobacter pylori in Israeli children

Objectives. To determine the antibiotic susceptibility of Helicobacter pylori isolates from Israeli children; assess the role of previous antibiotic use in the development of antibiotic resistance and examine the possibility of simultaneous colonization of strains with different resistance patterns in the same patients. Material and methods. A prospective case-series design was used. The study group included 174 patients aged 1-18 years referred to the Schneider Children's Medical Center of Israel for gastroscopy over a 2.5-year period. Antibiotic susceptibility to amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin was determined by E-test on gastric biopsies (2 per patient). Clinical and demographic data were obtained by questionnaire. Results. Cultures for H. pylori yielded 55 isolates from 53 children. In treatment-naive children, the prevalence rate of primary resistance to clarithromycin was 25% and to metronidazole, 19%. Respective rates in children previously treated for H. pylori infection were 42% (p = 0.22) and 52% (p = 0.016). Simultaneous resistance to both drugs was found in 13% of isolates (n = 7), all from children with previous treatment failure. No resistance was found to amoxicillin, tetracycline or levofloxacin. Clarithromycin resistance was associated with macrolide use for any indication during the previous year (p = 0.033). In 2 patients (3.8%), a different H. pylori strain was cultured from each biopsy. Conclusions. H. pylori resistance to clarithromycin and metronidazole is high in Israeli children, particularly in those previously treated for H. pylori infection, in whom culture-based treatment should be considered. The simultaneous colonization of multiple strains in a minority of patients needs to be further characterized.