Background: The aim of this study was to investigate the sensitivity of Helicobacter pylori to the antibiotics used in its eradication over a period of four years and to determine the influence of previous treatment on sensitivity.
Material and methods: During the period from 1995 to 1998 we determined the sensitivity of 235 consecutive Helicobacter pylori isolates to amoxicillin, metronidazole, clarythromycin and tetracycline by means of E-test methodology. The MIC values found were related with the prior use of eradicating treatment.
Results: The percentage of resistant strains were as follows: 23.5% to metronidazole, 12.9% to clarythromycin and 0.7% to tetracycline; none of the strains was resistant to amoxicillin. There were no significant changes in percentage of resistance to the drugs studied over the 4-year period. Resistance to metronidazole and clarythromycin was significantly higher (p 5 0.03 and p < 0.001 respectively) in strains isolated from patients who had received previous treatment.
Conclusions: Monitorization of H. pylori sensitivity to the drugs used in its eradication is particularly important in patients who have undergone prior treatment.