High level of resistance to metronidazole and clarithromycin in Helicobacter pylori isolated from pediatric patients in Poland (1997-2001).

Resistance to metronidazole (Met), clarithromycin (Cla) and amoxycillin (Amo) was examined using H. pylori isolates from child patients before and after treatment in the period 1997-2001. The rate of Met and Cla resistance before treatment was 35.2 and 8.6%, respectively. Six weeks after treatment 48.4% of the isolated strains were resistant to Met and 17.6% to Cla. The highest rate of resistance to both antibiotics was determined in 2001 (before treatment, 46 and 15%, respectively, and after treatment, 57.8 and 26.3%, respectively). All the strains were susceptible to Amo. Strains resistant to Met were detected more frequently in girls than in boys.