Prevalence of antibiotic resistance of Helicobacter pylori isolates in Estonia during 1995-2000 in comparison to the consumption of antibiotics used in treatment regimens

Objective To find a possible relation between the dynamics of antibiotic resistance of Helicobacter pylori isolates and the consumption of antibiotics during the last several years in Estonia. Methods Helicobacter pylori isolates were collected from the gastric mucosa of patients with peptic ulcer (153) and gastritis (68) and isolated on the Columbia Agar Base. From 1995 to 1997 the disk-diffusion method was used for testing of H. pylori susceptibility to metronidazole (115 isolates), erythromycin (119 isolates), tetracycline (119 isolates) and amoxicillin (119 isolates). From 1998 to 2000 the susceptibility of H. pylori to metronidazole (106 isolates), amoxicillin (30 isolates), clarithromycin (106 isolates) and ciprofloxacin (30 isolates) was assessed by E tests. Data from the Estonian State Agency of Medicines were used to determine the antibiotic consumption rate. Results Up to the year 2000 all the investigated H. pylori isolates were susceptible to ciprofloxacin; the resistance to clarithromycin, tetracycline, amoxicillin and erythromycin was 3%, 1.7%, 0.7% and 2.5%, respectively. Forty-six percent of H. pylori isolates were resistant to metronidazole. During 1995-2000 the consumption of amoxicillin, erythromycin and ciprofloxacin increased and the consumption of tetracycline decreased. The increasing consumption of amoxicillin reached a level 5.7 times than that of the consistent use of metronidazole. The resistance to amoxicillin appeared to be very low and resistance to metronidazole was continuously high. The increase of clarithromycin consumption (from 0.002 to 1.119 defined daily doses/1000) during three years was associated with the appearance of the first clarithromycin-resistant isolates in 2000. Conclusion No relation was observed between the antibiotic consumption rate and the resistance pattern of H. pylori to metronidazole, amoxicillin, erythromycin, tetracycline and ciprofloxacin during recent years among the in population.