[Evolution of the sensitivity of 235 strains of Helicobacter pylori from 1995 to 1998 and impact of antibiotic treatment]. / Evolución de la sensibilidad de 235 cepas de Helicobacter pylori entre 1995 y 1998 e impacto del tratamiento antibiótico.

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.

Evolución de la sensibilidad de 235 cepas de Helicobacter pylori entre 1995 y 1998 e impacto del tratamiento antibiótico / Sensitivity of 235 strains of Helicobacter pylori from 1995 to 1998 and impact of antibiotic treatment

FUNDAMENTO. Conocer la sensibilidad de Helicobacter pylori a los antibióticos utilizados en el tratamiento erradicador, su evolución temporal y la influencia de la utilización previa de dicho tratamiento. MATERIAL Y MÉTODOS. Se estudió mediante E-test la sensibilidad a amoxicilina, metronidazol, claritromicina y tetraciclina de 235 aislamientos consecutivos de Helicobacter pylori durante el período comprendido entre 1995 y 1998, y se relacionaron los valores de concentración mínima inhibitoria (CMI) hallados con la utilización previa de tratamiento erradicador. RESULTADOS. Se observó un porcentaje de resistencia a metronidazol de 23,5 por ciento, de 12,9 por ciento a claritromicina y de 0,7 por ciento a tetraciclina; ninguna de las cepas fue resistente a amoxicilina. No se observaron cambios significativos en los porcentajes de resistencia a lo largo del período estudiado. Los porcentajes de resistencia a metronidazol y claritromicina fueron significativamente más elevados (p 0,03 y p < 0,001, respectivamente) en las cepas aisladas de los pacientes que habían recibido tratamiento. CONCLUSIONES. Es necesaria la monitorización de la sensibilidad de H. pylori a los antibióticos utilizados en el tratamiento erradicador, especialmente en los pacientes previamente tratados 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 por ciento to metronidazole, 12.9 por ciento to clarythromycin and 0.7 por ciento 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 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 (AU)